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* [https://www.genomes2people.org/research/babyseq/ '''The BabySeq Project'''] "The BabySeq Project is a first-of-its-kind randomized clinical trial designed to examine how best to use genomics in clinical pediatric medicine by creating and safely testing methods for integrating sequencing into the care of newborns." [https://clinicaltrials.gov/ct2/show/NCT02422511 Clinical Trials]
* [https://www.genomes2people.org/research/babyseq/ '''The BabySeq Project'''] "The BabySeq Project is a first-of-its-kind randomized clinical trial designed to examine how best to use genomics in clinical pediatric medicine by creating and safely testing methods for integrating sequencing into the care of newborns." [https://clinicaltrials.gov/ct2/show/NCT02422511 Clinical Trials]


* '''The Impact of Sperm and Egg Donation on the Risk of Pregnancy Complications'''{{#pmid:30031370|PMID30031370}} "The aim of this study was to evaluate obstetric outcomes in relation to the extent of donor sperm exposure with and without egg donation. METHODS:  This is a retrospective cohort study in a single tertiary care center. All women with a singleton pregnancy who conceived following sperm donation (SD) were included. Obstetrics and neonatal outcomes for pregnancies following single SD were compared with pregnancies following repeat SD from the same donor. In a secondary analysis, we compared pregnancy outcomes among three modes of assisted reproductive technology (intrauterine insemination [IUI-SD], in vitro fertilization [IVF-SD], and IVF sperm + egg donation [IVF-SD + ED]). RESULTS:  A total of 706 pregnant women met the inclusion criteria, 243 (34.4%) following the first SD and 463 (65.6%) following repeat donations. Compared with repeat SDs, single donation was not associated with higher rates of preterm delivery (12.8 vs. 12.7%, respectively, p = 0.99), preeclampsia (7.0 vs. 6.9%, p = 0.999), and intrauterine growth restriction (4.1 vs. 3.9%, p = 0.88). Pregnancies following IVF-SD + ED had increased risk for preeclampsia (adjusted odds ratio [AOR], 3.1; 95% confidence interval [CI], 1.5-6.6), preterm labor (AOR, 2.4; 95% CI, 1.1-5.4), and cesarean section (AOR, 2.1; 95% CI, 1.0-4.3) compared with IUI-SD and IVF-SD. CONCLUSION:  The extent of donor sperm exposure did not correlate with obstetrics complications, but double gamete donation was associated with increased risk for preeclampsia, preterm labor, and cesarean section." (More? {{ART}} | {{spermatozoa}} | {{oocyte}}}
* '''The Impact of Sperm and Egg Donation on the Risk of Pregnancy Complications'''{{#pmid:30031370|PMID30031370}} "The aim of this study was to evaluate obstetric outcomes in relation to the extent of donor sperm exposure with and without egg donation.  This is a retrospective cohort study in a single tertiary care center. All women with a singleton pregnancy who conceived following sperm donation (SD) were included. Obstetrics and neonatal outcomes for pregnancies following single SD were compared with pregnancies following repeat SD from the same donor. In a secondary analysis, we compared pregnancy outcomes among three modes of assisted reproductive technology (intrauterine insemination [IUI-SD], in vitro fertilization [IVF-SD], and IVF sperm + egg donation [IVF-SD + ED]). A total of 706 pregnant women met the inclusion criteria, 243 (34.4%) following the first SD and 463 (65.6%) following repeat donations. Compared with repeat SDs, single donation was not associated with higher rates of preterm delivery (12.8 vs. 12.7%, respectively, p = 0.99), preeclampsia (7.0 vs. 6.9%, p = 0.999), and intrauterine growth restriction (4.1 vs. 3.9%, p = 0.88). Pregnancies following IVF-SD + ED had increased risk for preeclampsia (adjusted odds ratio [AOR], 3.1; 95% confidence interval [CI], 1.5-6.6), preterm labor (AOR, 2.4; 95% CI, 1.1-5.4), and cesarean section (AOR, 2.1; 95% CI, 1.0-4.3) compared with IUI-SD and IVF-SD.  The extent of donor sperm exposure did not correlate with obstetrics complications, but double gamete donation was associated with increased risk for preeclampsia, preterm labor, and cesarean section." (More? {{ART}} | {{spermatozoa}} | {{oocyte}}}


* '''Outcomes of Women Delivering at Very Advanced Maternal Age'''{{#pmid:30016194|PMID30016194}} "Retrospective cohort study using the Texas Public Use Data File, years 2013-2014 (96,879 deliveries). Maternal age was a three-level variable: 35-39 (referent), 40-44, and 45-59 years (VAMA). Adjusted risk ratios (aRRs) for the two older age groups for various obstetrical and nonobstetrical complications were calculated from log-binomial regression models. RESULTS: The sample consisted of 96,879 deliveries. In univariate analyses, a higher frequency (p < 0.05) of gestational diabetes, pregestational diabetes, chronic hypertension, pregnancy related hypertensive disorders, multiple gestation, oligohydramnios, polyhydramnios, placenta previa, postpartum hemorrhage, small for gestational age, intrauterine fetal death, and length of stay were noted in the two older maternal age groups compared to the youngest maternal age group. Multiple gestations were noted to be more frequent in the two older groups. The risk of the following outcomes was approximately doubled in VAMA women compared to the referent (all statistically significant): small for gestational age (aRR = 1.92), stillbirth (aRR = 2.12), and intrauterine fetal death (aRR = 1.96). CONCLUSIONS: This population-based study detected a dose-response association between maternal age and the risk of multiple maternal and fetal complications." (More? {{maternal age}})
* '''Outcomes of Women Delivering at Very Advanced Maternal Age'''{{#pmid:30016194|PMID30016194}} "Retrospective cohort study using the Texas Public Use Data File, years 2013-2014 (96,879 deliveries). Maternal age was a three-level variable: 35-39 (referent), 40-44, and 45-59 years (VAMA). Adjusted risk ratios (aRRs) for the two older age groups for various obstetrical and nonobstetrical complications were calculated from log-binomial regression models. The sample consisted of 96,879 deliveries. In univariate analyses, a higher frequency (p < 0.05) of gestational diabetes, pregestational diabetes, chronic hypertension, pregnancy related hypertensive disorders, multiple gestation, oligohydramnios, polyhydramnios, placenta previa, postpartum hemorrhage, small for gestational age, intrauterine fetal death, and length of stay were noted in the two older maternal age groups compared to the youngest maternal age group. Multiple gestations were noted to be more frequent in the two older groups. The risk of the following outcomes was approximately doubled in VAMA women compared to the referent (all statistically significant): small for gestational age (aRR = 1.92), stillbirth (aRR = 2.12), and intrauterine fetal death (aRR = 1.96). This population-based study detected a dose-response association between maternal age and the risk of multiple maternal and fetal complications." (More? {{maternal age}})


* '''Inefficient Crossover Maturation Underlies Elevated Aneuploidy in Human Female {{Meiosis}}'''{{#pmid:28262352|PMID28262352}}  "Meiosis is the cellular program that underlies gamete formation. For this program, crossovers between homologous chromosomes play an essential mechanical role to ensure regular segregation. We present a detailed study of crossover formation in human male and female meiosis, enabled by modeling analysis. Results suggest that recombination in the two sexes proceeds analogously and efficiently through most stages. However, specifically in female (but not male), ∼25% of the intermediates that should mature into crossover products actually fail to do so. Further, this "female-specific crossover maturation inefficiency" is inferred to make major contributions to the high level of chromosome mis-segregation and resultant aneuploidy that uniquely afflicts human female oocytes (e.g., giving Down syndrome). Additionally, crossover levels on different chromosomes in the same nucleus tend to co-vary, an effect attributable to global per-nucleus modulation of chromatin loop size. Maturation inefficiency could potentially reflect an evolutionary advantage of increased aneuploidy for human females." (More? {{meiosis}})
* '''Inefficient Crossover Maturation Underlies Elevated Aneuploidy in Human Female {{Meiosis}}'''{{#pmid:28262352|PMID28262352}}  "Meiosis is the cellular program that underlies gamete formation. For this program, crossovers between homologous chromosomes play an essential mechanical role to ensure regular segregation. We present a detailed study of crossover formation in human male and female meiosis, enabled by modeling analysis. Results suggest that recombination in the two sexes proceeds analogously and efficiently through most stages. However, specifically in female (but not male), ∼25% of the intermediates that should mature into crossover products actually fail to do so. Further, this "female-specific crossover maturation inefficiency" is inferred to make major contributions to the high level of chromosome mis-segregation and resultant aneuploidy that uniquely afflicts human female oocytes (e.g., giving Down syndrome). Additionally, crossover levels on different chromosomes in the same nucleus tend to co-vary, an effect attributable to global per-nucleus modulation of chromatin loop size. Maturation inefficiency could potentially reflect an evolutionary advantage of increased aneuploidy for human females." (More? {{meiosis}})
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Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Genetic+Abnormal+Development ''Genetic Abnormal Development''] | [http://www.ncbi.nlm.nih.gov/pubmed/?term=Decvelopmental+Genetic+Abnormalities ''Decvelopmental Genetic Abnormalities'']
Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Genetic+Abnormal+Development ''Genetic Abnormal Development''] | [http://www.ncbi.nlm.nih.gov/pubmed/?term=Developmental+Genetic+Abnormalities ''Developmental Genetic Abnormalities'']


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==Human Chromosomes==
==Human Chromosomes==


{{Human chromosomes}}
{|
| {{Human chromosome links}}
|-
| '''Idiogram Chromosome Banding''' - The term refers to the light and dark pattern, seen after staining with a dye, of individual chromosomes identified in metaphase. It is only in meiosis and mitosis during metaphase that chromosomes can be easily identified, during the normal cell life (interphase) the chromosomes are unravelled and distributed within the nucleus in chromosome territories. A band is that part of a chromosome which is clearly distinguishable from nearby regions by appearing darker or brighter with one or more banding techniques.
 
:[[:File:Human idiogram.jpg|'''Human Idiogram''']]: [[:File:Human_idiogram-chromosome_01.jpg|1]] | [[:File:Human_idiogram-chromosome_02.jpg|2]] | [[:File:Human_idiogram-chromosome_03.jpg|3]] | [[:File:Human_idiogram-chromosome_04.jpg|4]] | [[:File:Human_idiogram-chromosome_05.jpg|5]] | [[:File:Human_idiogram-chromosome_06.jpg|6]] | [[:File:Human_idiogram-chromosome_07.jpg|7]] | [[:File:Human_idiogram-chromosome_08.jpg|8]] | [[:File:Human_idiogram-chromosome_09.jpg|9]] | [[:File:Human_idiogram-chromosome_10.jpg|10]] | [[:File:Human_idiogram-chromosome_11.jpg|11]] | [[:File:Human_idiogram-chromosome_12.jpg|12]] | [[:File:Human_idiogram-chromosome_13.jpg|13]] | [[:File:Human_idiogram-chromosome_14.jpg|14]] | [[:File:Human_idiogram-chromosome_15.jpg|15]] | [[:File:Human_idiogram-chromosome_16.jpg|16]] | [[:File:Human_idiogram-chromosome_17.jpg|17]] | [[:File:Human_idiogram-chromosome_18.jpg|18]] | [[:File:Human_idiogram-chromosome_19.jpg|19]] | [[:File:Human_idiogram-chromosome_20.jpg|20]] | [[:File:Human_idiogram-chromosome_21.jpg|21]] | [[:File:Human_idiogram-chromosome_22.jpg|22]] | [[X Chromosome|X]] | [[Y Chromosome|Y]]
|-
| [[Abnormal Development - Genetic|'''Genetic abnormality locations''']]: [[:File:Human_genetics_chromosomes_1-4.jpg|1-4]] | [[:File:Human_genetics_chromosomes_5-8.jpg|5-8]] | [[:File:Human_genetics_chromosomes_9-12.jpg|9-12]] | [[:File:Human_genetics_chromosomes_13-16.jpg|13-16]] | [[:File:Human_genetics_chromosomes_17-20.jpg|17-20]] | [[:File:Human_genetics_chromosomes_21-XY.jpg|21-XY]] | [[Small supernumerary marker chromosome|sSMC]]
 
|-
| {{GHR Inheritance}}
|-
| '''Links:''' [[Molecular_Development_-_Genetics|Genetics]] | [[Abnormal Development - Genetic]]
|}


==Human Oocyte Aneuploidy==
==Human Oocyte Aneuploidy==
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The term trisomy refers to the abnormal copy number of a specific chromosome, that is 3 copies instead of 2. The abnormality is identified by the chromosome that is present as 3 copies within the cell.
The term trisomy refers to the abnormal copy number of a specific chromosome, that is 3 copies instead of 2. The abnormality is identified by the chromosome that is present as 3 copies within the cell.


In humans, the most common trisomy is {{trisomy 21}} or Down syndrome. Other identified human trisomies include {{Trisomy 13}}, {{Trisomy 18}} and {{Trisomy X}}.
In humans, the most common trisomy is {{trisomy 21}} or Down syndrome. Other identified human trisomies include {{Trisomy 13}}, {{Trisomy 18}} and {{Trisomy X}}. Trisomies for other chromosomes are mainly placental in origin and can be associated with miscarriage and growth restriction, or with true fetal mosaicism.


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There have also been a number of trisomy mosaicisms identified for the above and other chromosomes.  A "mosaicism" is a rare chromosome disorder characterized by having an extra copy of a chromosome in a proportion, but not all, of a person’s cells.  
There have also been a number of trisomy mosaicisms identified for the above and other chromosomes.  A "mosaicism" is a rare chromosome disorder characterized by having an extra copy of a chromosome in a proportion, but not all, of a person’s cells.  


* '''Trisomy 22 mosaicism''' [https://rarediseases.org/rare-diseases/chromosome-22-trisomy-mosaic/ Rare Disease Database] - The characteristic features of mosaic trisomy 22 typically include prenatal and postnatal growth failure or delay, asymmetrical development of the two sides of the body (hemidystrophy), congenital heart defects. While some patients with mosaic trisomy 22 have abnormal cognitive development, normal development has been documented for some children."
Identified human examples of this disorder include: [[Trisomy_Mosaicism#Trisomy_22_Mosaicism|Trisomy 22 mosaicism]], [[Trisomy_Mosaicism#Trisomy_18_Mosaicism|Trisomy 18 mosaicism]], [[Trisomy_Mosaicism#Trisomy_17_Mosaicism|Trisomy 17 mosaicism]], [[Trisomy_Mosaicism#Trisomy_14_Mosaicism|Trisomy 14 mosaicism]], [[Trisomy_Mosaicism#Trisomy_12_Mosaicism|Trisomy 12 mosaicism]], [[Trisomy_Mosaicism#Trisomy_9_Mosaicism|Trisomy 9 mosaicism]], [[Trisomy_Mosaicism#Trisomy_8_Mosaicism|Trisomy 8 mosaicism]], and [[Trisomy_Mosaicism#Trisomy_2_Mosaicism|Trisomy 2 mosaicism]].
 
* '''Trisomy 18 mosaicism'''{{#pmid:8779322|PMID8779322}} - "Blood lymphocyte and skin fibroblast karyotypes were normal. He died in the neonatal period of postoperative complications. On interphase fluorescence in-situ hybridization (FISH) using autopsy specimens, a significant number of cells in the liver (17%) were trisomic for chromosome 18, compared to normal control liver tissue. However, interphase FISH analyses of blood lymphocytes, skin fibroblasts, and kidney tissue were normal."
 
* '''Trisomy 17 mosaicism''' [https://rarediseases.info.nih.gov/diseases/5317/trisomy-17-mosaicism NIH - rare diseases] - "Some cases of trisomy 17 mosaicism detected during pregnancy have been confirmed in the baby after birth. The symptoms reported include: developmental delays, body asymmetry, slow growth, and cerebellar hypoplasia. Again, signs and symptoms may vary in these individuals depending on which cells and how many cells contain an extra chromosome 17."
 
* '''Trisomy 14 mosaicism''' [https://rarediseases.org/rare-diseases/chromosome-14-trisomy-mosaic/ Rare Disease Database] - "The disorder may be characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failure to thrive) during infancy; delays in the acquisition of skills requiring the coordination of mental and physical abilities (psychomotor delays); and mental retardation. Affected infants also have distinctive abnormalities of the head and facial (craniofacial) region, such as a prominent forehead; deeply set, widely spaced eyes; a broad nasal bridge; and low-set, malformed ears. Additional craniofacial abnormalities may include an unusually small lower jaw (micrognathia); a large mouth and thick lips; and incomplete closure or abnormally high arching of the roof of the mouth (palate). Many affected infants also have structural malformations of the heart (e.g., tetralogy of Fallot). In some cases, additional physical abnormalities may also be present."
 
* '''Trisomy 12 mosaicism'''{{#pmid:11146464|PMID11146464}} - "meiotic origin of the trisomy, maternal meiosis I, was determined. Mosaic aneuploidy was suspected because of pigmentary dysplasia, a frequent but non-specific finding in chromosomal mosaicism. The severe phenotype of this child, who died in infancy with a complex heart malformation, was probably a result of the high percentage of trisomic cells. Cytogenetic and interphase fluorescent in situ hybridization analyses showed a highly variable distribution of aneuploid cells in the nine tissues studied, from none in blood and ovary to 100% in spleen and liver."
 
* '''Trisomy 9 mosaicism''' [https://rarediseases.org/rare-diseases/chromosome-9-trisomy-mosaic/ Rare Disease Database] - "Associated symptoms and findings may vary greatly in range and severity, depending on the percentage of cells with the extra chromosome. However, common features include growth deficiency before birth (intrauterine growth restriction or IUGR); structural malformations of the heart that are present at birth (congenital heart defects); and/or distinctive differences in the shape of the skull and facial (craniofacial) region, such as a sloping forehead, a bulbous nose, short eyelid folds (palpebral fissures), deeply set eyes, and/or low-set ears. The syndrome may also be characterized by musculoskeletal, genital, kidney (renal), and/or additional physical anomalies. Intellectual disability is common and varies in severity."
 
* '''Trisomy 8 mosaicism''' [https://rarediseases.info.nih.gov/diseases/5359/mosaic-trisomy-8 NIH - rare diseases] - "The signs and symptoms vary, but may include distinctive facial features; intellectual disability; and joint, kidney, cardiac, and skeletal abnormalities. Males are more frequently affected than females."


* '''Trisomy 2 mosaicism'''{{#pmid:15539872|PMID15539872}} [https://rarediseases.info.nih.gov/diseases/5331/trisomy-2-mosaicism NIH - rare diseases] -  "Features of trisomy 2 mosaicism may include intrauterine growth restriction (IUGR), any of various birth defects, distinctive facial features, growth delay, developmental delays, and intellectual disabilities.[1][2] However, children with trisomy 2 mosaicism with no significant medical problems have been reported (although long-term follow-up was not available)."


:'''Links:''' {{Trisomy mosaicism}}


===Ring Chromosome===
===Ring Chromosome===

Revision as of 16:33, 19 March 2019

Embryology - 28 Mar 2024    Facebook link Pinterest link Twitter link  Expand to Translate  
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العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

Educational Use Only - Embryology is an educational resource for learning concepts in embryological development, no clinical information is provided and content should not be used for any other purpose.

Introduction

Chromosomes in trisomy 21

This page gives a general introduction to information about genetic abnormalities their relationship to age, ethnicity and prenatal testing. Use the listed links for more information about specific abnormalities. In developed countries with increasing maternal age comes the increased risk of age related genetic abnormalities, such as trisomy 21.

In order to detect some genetic abnormalities many countries offer genetic screening programs that include maternal serum screening (MSS, for detection of Down's syndrome and neural tube defects), embryonic and newborn screening (for phenylketonuria (PKU), hypothyroidism, cystic fibrosis and metabolic disorders).

In terms of maternal/paternal family history, some ethnic backgrounds have been shown to have disease-associated genetic variants, though most common genetic diseases are consistent across ethnic boundaries. For example: Caucasians of northern European ancestry and cystic fibrosis (CTFR gene), Mediterranean, Asian and Far Eastern ancestry with beta-thalassaemia.

Note that the development of in vitro fertilization techniques now allows cells from early stage blastocysts to be removed and genetically analysed prior to implantation. This has raised some ethical issues relating to what parameters will be in future used in blastocyst selection.

Genetic Links: genetic abnormalities | maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Trisomy X | trisomy mosaicism | Monosomy | Fragile X | Williams | Alagille | Philadelphia chromosome | mitochondria | VACTERL | hydatidiform mole | epigenetics | Prenatal Diagnosis | Neonatal Diagnosis | meiosis | mitosis | International Classification of Diseases | genetics


Abnormality Links: abnormal development | abnormal genetic | abnormal environmental | Unknown | teratogens | ectopic pregnancy | cardiovascular abnormalities | coelom abnormalities | endocrine abnormalities | gastrointestinal abnormalities | genital abnormalities | head abnormalities | integumentary abnormalities | musculoskeletal abnormalities | limb abnormalities | neural abnormalities | neural crest abnormalities | placenta abnormalities | renal abnormalities | respiratory abnormalities | hearing abnormalities | vision abnormalities | twinning | Developmental Origins of Health and Disease |  ICD-11
Historic Embryology  
1915 Congenital Cardiac Disease | 1917 Frequency of Anomalies in Human Embryos | 1920 Hydatiform Degeneration Tubal Pregnancy | 1921 Anencephalic Embryo | 1921 Rat and Man | 1966 Congenital Malformations

Some Recent Findings

Human idiogram
  • The BabySeq Project "The BabySeq Project is a first-of-its-kind randomized clinical trial designed to examine how best to use genomics in clinical pediatric medicine by creating and safely testing methods for integrating sequencing into the care of newborns." Clinical Trials
  • The Impact of Sperm and Egg Donation on the Risk of Pregnancy Complications[1] "The aim of this study was to evaluate obstetric outcomes in relation to the extent of donor sperm exposure with and without egg donation.  This is a retrospective cohort study in a single tertiary care center. All women with a singleton pregnancy who conceived following sperm donation (SD) were included. Obstetrics and neonatal outcomes for pregnancies following single SD were compared with pregnancies following repeat SD from the same donor. In a secondary analysis, we compared pregnancy outcomes among three modes of assisted reproductive technology (intrauterine insemination [IUI-SD], in vitro fertilization [IVF-SD], and IVF sperm + egg donation [IVF-SD + ED]). A total of 706 pregnant women met the inclusion criteria, 243 (34.4%) following the first SD and 463 (65.6%) following repeat donations. Compared with repeat SDs, single donation was not associated with higher rates of preterm delivery (12.8 vs. 12.7%, respectively, p = 0.99), preeclampsia (7.0 vs. 6.9%, p = 0.999), and intrauterine growth restriction (4.1 vs. 3.9%, p = 0.88). Pregnancies following IVF-SD + ED had increased risk for preeclampsia (adjusted odds ratio [AOR], 3.1; 95% confidence interval [CI], 1.5-6.6), preterm labor (AOR, 2.4; 95% CI, 1.1-5.4), and cesarean section (AOR, 2.1; 95% CI, 1.0-4.3) compared with IUI-SD and IVF-SD.  The extent of donor sperm exposure did not correlate with obstetrics complications, but double gamete donation was associated with increased risk for preeclampsia, preterm labor, and cesarean section." (More? ART | spermatozoa | oocyte}
  • Outcomes of Women Delivering at Very Advanced Maternal Age[2] "Retrospective cohort study using the Texas Public Use Data File, years 2013-2014 (96,879 deliveries). Maternal age was a three-level variable: 35-39 (referent), 40-44, and 45-59 years (VAMA). Adjusted risk ratios (aRRs) for the two older age groups for various obstetrical and nonobstetrical complications were calculated from log-binomial regression models. The sample consisted of 96,879 deliveries. In univariate analyses, a higher frequency (p < 0.05) of gestational diabetes, pregestational diabetes, chronic hypertension, pregnancy related hypertensive disorders, multiple gestation, oligohydramnios, polyhydramnios, placenta previa, postpartum hemorrhage, small for gestational age, intrauterine fetal death, and length of stay were noted in the two older maternal age groups compared to the youngest maternal age group. Multiple gestations were noted to be more frequent in the two older groups. The risk of the following outcomes was approximately doubled in VAMA women compared to the referent (all statistically significant): small for gestational age (aRR = 1.92), stillbirth (aRR = 2.12), and intrauterine fetal death (aRR = 1.96). This population-based study detected a dose-response association between maternal age and the risk of multiple maternal and fetal complications." (More? maternal age)
  • Inefficient Crossover Maturation Underlies Elevated Aneuploidy in Human Female meiosis[3] "Meiosis is the cellular program that underlies gamete formation. For this program, crossovers between homologous chromosomes play an essential mechanical role to ensure regular segregation. We present a detailed study of crossover formation in human male and female meiosis, enabled by modeling analysis. Results suggest that recombination in the two sexes proceeds analogously and efficiently through most stages. However, specifically in female (but not male), ∼25% of the intermediates that should mature into crossover products actually fail to do so. Further, this "female-specific crossover maturation inefficiency" is inferred to make major contributions to the high level of chromosome mis-segregation and resultant aneuploidy that uniquely afflicts human female oocytes (e.g., giving Down syndrome). Additionally, crossover levels on different chromosomes in the same nucleus tend to co-vary, an effect attributable to global per-nucleus modulation of chromatin loop size. Maturation inefficiency could potentially reflect an evolutionary advantage of increased aneuploidy for human females." (More? meiosis)
More recent papers  
Mark Hill.jpg
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This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.

  • This search now requires a manual link as the original PubMed extension has been disabled.
  • The displayed list of references do not reflect any editorial selection of material based on content or relevance.
  • References also appear on this list based upon the date of the actual page viewing.


References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

More? References | Discussion Page | Journal Searches | 2019 References | 2020 References


Search term: Genetic Abnormal Development | Developmental Genetic Abnormalities

Older papers  
These papers originally appeared in the Some Recent Findings table, but as that list grew in length have now been shuffled down to this collapsible table.

See also the Discussion Page for other references listed by year and References on this current page.

  • Maternal Age-Specific Rates for Trisomy 21 and Common Autosomal Trisomies in Fetuses from a Single Diagnostic Center in Thailand[4] "We retrospectively reviewed prenatal cytogenetic results obtained between 1990 and 2009 in Songklanagarind Hospital, a university teaching hospital, in southern Thailand. Maternal age-specific rates of T21 and common autosomal trisomies were established using different regression models, from which only the fittest models were used for the study. A total of 17,819 records were included in the statistical analysis. The fittest models for predicting rates of T21 and common autosomal trisomies were regression models with 2 parameters (Age and Age2). The rate of T21 ranged between 2.67 per 1,000 fetuses at the age of 34 and 71.06 per 1,000 at the age of 48. The rate of common autosomal trisomies ranged between 4.54 per 1,000 and 99.65 per 1,000 at the same ages. This report provides the first maternal age-specific rates for T21 and common autosomal trisomies fetuses in a Southeast Asian population and the largest case number of fetuses have ever been reported in Asians." (More? maternal age)
  • Responsible innovation in human germline gene editing: Background document to the recommendations of ESHG and ESHRE[5] "Technological developments in gene editing raise high expectations for clinical applications, including editing of the germline. The European Society of Human Reproduction and Embryology (ESHRE) and the European Society of Human Genetics (ESHG) together developed a Background document and Recommendations to inform and stimulate ongoing societal debates. This document provides the background to the Recommendations. Germline gene editing is currently not allowed in many countries. This makes clinical applications in these countries impossible now, even if germline gene editing would become safe and effective. What were the arguments behind this legislation, and are they still convincing?" (More? Human germline gene editing: Recommendations PMID 29326428)
  • Sex ratios among infants with birth defects, National Birth Defects Prevention Study, 1997-2009[6] "A small number of population-based studies have examined sex differences among infants with birth defects. The highest elevations in sex ratios (i.e., male preponderance) among isolated non-cardiac defects were for craniosynostosis (2.12), cleft lip with cleft palate (2.01), and cleft lip without cleft palate (1.78); the lowest sex ratios (female preponderance) were for choanal atresia (0.45), cloacal exstrophy (0.46), and holoprosencephaly (0.64). Among isolated cardiac defects, the highest sex ratios were for aortic stenosis (2.88), coarctation of the aorta (2.51), and d-transposition of the great arteries (2.34); the lowest were multiple ventricular septal defects (0.52), truncus arteriosus (0.63), and heterotaxia with congenital heart defect (0.64)."
  • Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies[7] "Available evidence strongly supports the use of chromosomal microarray (CMA) in place of G-banded karyotyping as the first-tier cytogenetic diagnostic test for patients with developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), or multiple congenital anomalies (MCA). G-banded karyotype analysis should be reserved for patients with obvious chromosomal syndromes (e.g., Down syndrome), a family history of chromosomal rearrangement, or a history of multiple miscarriages."
  • Maternal genes and facial clefts in offspring: a comprehensive search for genetic associations in two population-based cleft studies from Scandinavia[8] "Except for FLNB, HIC1 and ZNF189, maternal genes did not appear to influence the risk of clefting in our data. This is consistent with recent epidemiological findings showing no apparent difference between mother-to-offspring and father-to-offspring recurrence of clefts in these two populations. It is likely that fetal genes make the major genetic contribution to clefting risk in these populations, but we cannot rule out the possibility that maternal genes can affect risk through interactions with specific teratogens or fetal genes."
  • Altered intra-nuclear organisation of heterochromatin and genes in ICF syndrome[9] "The ICF syndrome is a rare autosomal recessive disorder, the most common symptoms of which are immunodeficiency, facial anomalies and cytogenetic defects involving decondensation and instability of chromosome 1, 9 and 16 centromeric regions. ...DNA hypomethylation, previously reported to correlate with the decondensation of centromeric regions in metaphase described in these patients, appears also to correlate with the heterochromatin spatial configuration in interphase. "

ICD-11 Chromosomal Anomalies

The International Classification of Diseases (ICD) World Health Organization's classification used worldwide as the standard diagnostic tool for epidemiology, health management and clinical purposes.

ICD-11 Chromosomal anomalies excluding gene mutations  
  • LD40 Complete trisomies of the autosomes
  • LD41 Duplications of the autosomes
  • LD42 Polyploidies
  • LD43 Complete monosomies of the autosomes
  • LD44 Deletions of the autosomes
  • LD45 Uniparental disomies
  • LD46 Imprinting errors
  • LD47 Balanced rearrangements or structural markers
Sex chromosome anomalies
  • LD50 Number anomalies of chromosome X  
  • LD51 Structural anomalies of chromosome X, excluding Turner syndrome
  • LD52 Number anomalies of chromosome Y
  • LD53 Structural anomalies of chromosome Y
  • LD54 Male with sex chromosome mosaicism
  • LD55 Fragile X chromosome
  • LD56 Chimaera 46, XX, 46, XY  
LD5Y Other specified sex chromosome anomalies  
LD5Z Sex chromosome anomalies, unspecified  
LD7Y Other specified chromosomal anomalies, excluding gene mutations

LD7Z Chromosomal anomalies, excluding gene mutations, unspecified

genetic abnormalities
ICD-11 Links:  ICD-11 | Anomalies one body system | Multiple anomalies or syndromes | Chromosomal anomalies | Intellectual development | Abnormal Development | Prenatal Diagnosis | Birth | Neonatal Diagnosis | ICD-10 | Reports | | Category:ICD-11

Human Chromosomes

Human Chromosomes: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | X | Y  
Idiogram Chromosome Banding - The term refers to the light and dark pattern, seen after staining with a dye, of individual chromosomes identified in metaphase. It is only in meiosis and mitosis during metaphase that chromosomes can be easily identified, during the normal cell life (interphase) the chromosomes are unravelled and distributed within the nucleus in chromosome territories. A band is that part of a chromosome which is clearly distinguishable from nearby regions by appearing darker or brighter with one or more banding techniques.
Human Idiogram: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | X | Y
Genetic abnormality locations: 1-4 | 5-8 | 9-12 | 13-16 | 17-20 | 21-XY | sSMC
Inheritance Pattern images: Genetic Abnormalities | autosomal dominant | autosomal recessive | X-linked dominant (affected father) | X-Linked dominant (affected mother) | X-Linked recessive (affected father) | X-Linked recessive (carrier mother) | mitochondrial inheritance | Codominant inheritance | Genogram symbols | Genetics
Links: Genetics | Abnormal Development - Genetic

Human Oocyte Aneuploidy

  • Frequency and distribution of chromosome abnormalities in human oocytes[10] "It was previously shown that more than half of the human oocytes obtained from IVF patients of advanced reproductive age are aneuploid, due to meiosis I and meiosis II errors. The present paper further confirms that 61.8% of the oocytes tested by fluorescent probes specific for chromosomes 13, 16, 18, 21 and 22 are abnormal, representing predominantly chromatid errors, which are the major source of aneuploidy in the resulting embryos. Almost half of the oocytes with meiosis I errors (49.3%) are prone to sequential meiosis II errors, which may lead to aneuploidy rescue in 30.8% of the cases. Half of the detected aneuploidies (49.8%) are of complex nature with involvement of two or more chromosomes, or the same chromosome in both meiotic divisions. The aneuploidy rates for individual chromosomes are different, with a higher prevalence of chromosome 21 and 22 errors. The origin of aneuploidy for the individual chromosomes is also not random, with chromosome 16 and 22 errors originating more frequently in meiosis II, and chromosome 18, 13 and 21 errors in meiosis I. There is an age dependence not only for the overall frequency of aneuploidies, but also for each chromosome error, aneuploidies originating from meiosis I, meiosis II, and both meiosis I and meiosis II errors, as well as for different types of aneuploidies. The data further suggest the practical relevance of oocyte aneuploidy testing for detection and avoidance from transfer of the embryos deriving from aneuploid oocytes, which should contribute significantly to the pregnancy outcomes of IVF patients of advanced reproduction age."


Links: Genetic risk maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Oocyte Development

Embryonic Aneuploidy

Aneuploidy model based on fragmentation 1.jpg

Embryonic aneuploidy model based on fragmentation.[11] (See also Fragmentation Model and Monosomic Embryo Movie)

Some Human Disease Gene Locations

Human genetics chromosomes 1-4.jpg

Human genetics chromosomes 5-8.jpg

Human genetics chromosomes 9-12.jpg

Human genetics chromosomes 17-20.jpg

Human genetics chromosomes 21-XY.jpg


Genetic Inheritance

The figures below show the pattern of inheritance of a range of genetic disorders. In addition to these patterns are the known effects of increased maternal age and the effects of genetic mutations in the embryo and newborn.

Inheritance Pattern images: Genetic Abnormalities | autosomal dominant | autosomal recessive | X-linked dominant (affected father) | X-Linked dominant (affected mother) | X-Linked recessive (affected father) | X-Linked recessive (carrier mother) | mitochondrial inheritance | Codominant inheritance | Genogram symbols | Genetics


An example of autosomal recessive traits are the majority of 50 or so lysosomal diseases, with two X-linked exceptions, that of Fabry disease and Mucopolysaccharidosis II.[12]

Carrier Testing

Preconception carrier tests are available for some autosomal recessive (AR) diseases. These were initially developed for autosomal recessive diseases that were frequent in specific ethnic groups:

  • Tay–Sachs disease - Ashkenazi Jews
  • hemoglobinopathies - Mediterranean and African populations
  • cystic fibrosis - European-derived populations

Genome-wide association study

The National Human Genome Research Institute (USA) lists publications as part of the genome-wide association study (GWAS) in an attempt to assay at least 100,000 single nucleotide polymorphisms (SNPs) in the initial stage.

Links: Genome-wide association study | National Human Genome Research Institute

Fertility

Male Infertility Genes

Selected genes in Male Infertility
Gene abbreviation Name Gene Location Online Mendelian
Inheritance in Man (OMIM)
HUGO Gene Nomenclature
Committee (HGNC)
GeneCards (GCID) Diagnosis
AURKC Aurora kinase C 19q13.43 603495 11391 GC19P057230 Macrozoospermia
CATSPER1 Cation channel sperm-associated 1 11q13.1 606389 17116 GC11M066034 Asthenozoospermia
CFTR Cystic fibrosis transmembrane conductance regulator 7q31.2 602421 1884 GC07P117465 Obstructive azoospermia
DNAH1 Dynein axonemal heavy chain 1 3p21.1 603332 2940 GC03P052350 Asthenozoospermia
DPY19L2 Dpy-19-like 2 gene 12q14.2 613893 19414 GC12M063558 Globozoospermia
GALNTL5 Polypeptide N-acetylgalactosaminyltransferase-like 5 7q36.1 615133 21725 GC07P151956 Asthenozoospermia
MAGEB4 MAGE family member B4 Xp21.2 300153 6811 GC0XP030260 Azoospermia
NANOS1 Nanos C2HC-type zinc finger 1 10q26.11 608226 23044 GC10P119029 Azoospermia
NR0B1 Nuclear receptor subfamily 0 group B member 1 Xp21.2 300473 7960 GC0XM030322 Azoospermia
NR5A1 Nuclear receptor subfamily 5 group A member 1 9q33.3 184757 7983 GC09M124481 Azoospermia
SOHLH1 Spermatogenesis and oogenesis-specific basic helix–loop–helix 1 9q34.3 610224 27845 C09M135693 Azoospermia
vSPATA16 Spermatogenesis-associated 16 3q26.31 609856 29935 GC03M172889 Globozoospermia
SYCE1 Synaptonemal complex central element protein 1 10q26.3 611486 28852 GC10M133553 Azoospermia
TAF4B TATA-box binding protein-associated factor 4b 18q11.2 601689 11538 GC18P026225 Azoospermia
TEX11 Testis expressed 11 Xq13.1 300311 11733 GC0XM070528 Azoospermia
TEX15 Testis expressed 15, meiosis and synapsis associated 8p12 605795 11738 GC08M030808 Azoospermia
WT1 Wilms tumour 1 8p12 607102 12796 GC11M032365 Azoospermia
ZMYND15 Zinc-finger MYND-type containing 15 17p13.2 614312 20997 GC17P004740 Azoospermia
  Table data source[13] (table 1)    Links: fertilization | spermatozoa | testis | Male Infertility Genes | Female Infertility Genes | oocyte | ovary | Genetic Abnormalities | ART

  Asthenozoospermia - (asthenospermia) term for reduced spermatozoa motility. Azoospermia - term for no spermatozoa located in the ejaculate. Globozoospermia - term for spermatozoa with a round head and no acrosome.

Female Infertility Genes

Selected Female Infertility Genes
Gene abbreviation Name Gene Location Online Mendelian
Inheritance in Man (OMIM)
HUGO Gene Nomenclature
Committee (HGNC)
GeneCards (GCID) Diagnosis
BMP15 Bone morphogenetic protein 15 Xp11.22 300247 1068 GC0XP050910 Primary ovarian insufficiency
CLPP Caseinolytic mitochondrial matrix peptidase proteolytic subunit 19p13.3 601119 2084 GC19P006369 Primary ovarian insufficiency
EIF2B2 Eukaryotic translation initiation factor 2B subunit beta 14q24.3 606454 3258 GC14P075002 Primary ovarian insufficiency
FIGLA Folliculogenesis-specific BHLH transcription factor 2p13.3 608697 24669 GC02M070741 Primary ovarian insufficiency
FMR1 Fragile X mental retardation 1 Xq27.3 309550 3775 GC0XP147912 Primary ovarian insufficiency
FOXL2 Forkhead box L2 3q22.3 605597 1092 GC03M138944 Primary ovarian insufficiency
FSHR Follicle stimulating hormone receptor 2p16.3 136435 3969 GC02M048866 Primary ovarian insufficiency
GALT Galactose-1-phosphate uridylyltransferase 9p13.3 606999 4135 GC09P034636 Primary ovarian insufficiency
GFD9 Growth differentiation factor 9 5q31.1 601918 4224 GC05M132861 Primary ovarian insufficiency
HARS2 Histidyl-TRNA synthetase 2, mitochondrial 5q31.3 600783 4817 GC05P141975 Primary ovarian insufficiency
HFM1 HFM1, ATP-dependent DNA helicase homolog 1p22.2 615684 20193 GC01M091260 Primary ovarian insufficiency
HSD17B4 Hydroxysteroid 17-beta dehydrogenase 4 5q23.1 601860 5213 GC05P119452 Primary ovarian insufficiency
LARS2 Leucyl-TRNA synthetase 2, mitochondrial 3p21.31 604544 17095 GC03P045405 Primary ovarian insufficiency
LHCGR Luteinizing hormone/choriogonadotropin receptor 2p16.3 152790 6585 GC02M048647 Primary ovarian insufficiency
LHX8 LIM homeobox 8 1p31.1 604425 28838 GC01P075128 Primary ovarian insufficiency
MCM8 Minichromosome maintenance 8 homologous recombination repair factor 20p12.3 608187 16147 GC20P005926 Primary ovarian insufficiency
MCM9 Minichromosome maintenance 9 homologous recombination repair factor 6q22.31 610098 21484 GC06M118813 Primary ovarian insufficiency
NOBOX NOBOX oogenesis homeobox 7q35 610934 22448 GC07M144397 Primary ovarian insufficiency
NOG Noggin 17q22 602991 7866 GC17P056593 Primary ovarian insufficiency
PMM2 Phosphomannomutase 2 16p13.2 601785 9115 GC16P008788 Primary ovarian insufficiency
POLG DNA polymerase gamma, catalytic subunit 15q26.1 174763 9179 GC15M089316 Primary ovarian insufficiency
REC8 REC8 meiotic recombination protein 14q12 608193 16879 GC14P024171 Primary ovarian insufficiency
SMC1B Structural maintenance of chromosomes 1B 22q13.31 608685 11112 GC22M045344 Primary ovarian insufficiency
SOHLH1 Spermatogenesis and oogenesis-specific basic helix–loop–helix 1 9q34.3 610224 27845 GC09M135693 Primary ovarian insufficiency
STAG3 Stromal antigen 3 7q22.1 {{Chr 608489 11356 GC07P100177 Primary ovarian insufficiency
SYCE1 Synaptonemal Complex Central Element Protein 1 10q26.3 611486 28852 GC10M133553 Primary ovarian insufficiency
TLE6 Transducin-like enhancer of split 6 19p13.3 612399 30788 GC19P002976 Embryonic lethalithy
TUBB8 Tubulin beta 8 Class VIII 10p15.3 616768 20773 GC10M000048 Oocyte maturation arrest
TWNK Twinkle MtDNA helicase 10q24.31 606075 1160 GC10P100991 Primary ovarian insufficiency
  Table data source[13] (table 1)    Links: fertilization | oocyte | ovary | | Female Infertility Genes | spermatozoa | testis | Male Infertility Genes | Genetic Abnormalities | ART

 Primary ovarian insufficiency - depletion or dysfunction of ovarian follicles with cessation of menses before age 40 years.
 Oocyte maturation arrest - arrest of human oocytes may occur at different stages of meiosis.

Genetic Abnormality Topics

Genetic Risk Maternal Age

Genetic Risk Maternal Age
Age of Mother
Risk of Trisomy 21
Risk of Any Chromosomal Abnormality
20
1 in 1667
1 in 526
21
1 in 1667
1 in 526
22
1 in 1429
1 in 500
23
1 in 1429
1 in 500
24
1 in 1250
1 in 476
25
1 in 1250
1 in 476
26
1 in 1176
1 in 476
27
1 in 1111
1 in 455
28
1 in 1053
1 in 435
29
1 in 1000
1 in 417
30
1 in 952
1 in 384
31
1 in 909
1 in 384
32
1 in 769
1 in 323
33
1 in 625
1 in 286
34
1 in 500
1 in 238
35
1 in 385
1 in 192
36
1 in 294
1 in 156
37
1 in 227
1 in 127
38
1 in 175
1 in 102
39
1 in 137
1 in 83
40
1 in 106
1 in 66
41
1 in 82
1 in 53
42
1 in 64
1 in 42
43
1 in 50
1 in 33
44
1 in 38
1 in 26
45
1 in 30
1 in 21
46
1 in 23
1 in 16
47
1 in 18
1 in 13
48
1 in 14
1 in 10
49
1 in 11
1 in 8
Table Data[14][15][16]
Genetic Links: genetic abnormalities | maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Trisomy X | trisomy mosaicism | Monosomy | Fragile X | Williams | Alagille | Philadelphia chromosome | mitochondria | VACTERL | hydatidiform mole | epigenetics | Prenatal Diagnosis | Neonatal Diagnosis | meiosis | mitosis | International Classification of Diseases | genetics


Trisomy

The term trisomy refers to the abnormal copy number of a specific chromosome, that is 3 copies instead of 2. The abnormality is identified by the chromosome that is present as 3 copies within the cell.

In humans, the most common trisomy is Trisomy 21 or Down syndrome. Other identified human trisomies include Trisomy 13, Trisomy 18 and Trisomy X. Trisomies for other chromosomes are mainly placental in origin and can be associated with miscarriage and growth restriction, or with true fetal mosaicism.

Trisomy Mosaicisms

There have also been a number of trisomy mosaicisms identified for the above and other chromosomes. A "mosaicism" is a rare chromosome disorder characterized by having an extra copy of a chromosome in a proportion, but not all, of a person’s cells.

Identified human examples of this disorder include: Trisomy 22 mosaicism, Trisomy 18 mosaicism, Trisomy 17 mosaicism, Trisomy 14 mosaicism, Trisomy 12 mosaicism, Trisomy 9 mosaicism, Trisomy 8 mosaicism, and Trisomy 2 mosaicism.


Links: trisomy mosaicism

Ring Chromosome

Ring chromosomal 15.jpg

Ring chromosomal 15

Selected Topics

Mutagen

A chemical or agent that can cause permanent damage to the genetic material, DeoxyriboNucleic Acid (DNA) in a cell. DNA damage in the human oocyte or spermatozoa may lead to reduced fertility, spontaneous abortion (miscarriage), birth defects and heritable diseases. DNA damage postnatally can lead to a variety of tumours.

There are a large number of known mutagenic agents including those that are physical, chemical or biological in origin.

Neonatal Testing

The main neonatal genetic test is the Bloodspot Test also known as the Guthrie Test.

Bloodspot Test or Guthrie Test

Guthrie card

A blood screening test developed by Dr Robert Guthrie (1916-95) at University of Buffalo.[17] The test is carried out on neonatal (newborn) blood detecting markers for a variety of known disorders (phenylketonuria (PKU), hypothyroidism and cystic fibrosis).

Links: Guthrie test | neonatal diagnosis

Australia - NSW Newborn Screening Programme

Each year test more than 90,000 babies and detects about 90 who need urgent assessment and treatment. In NSW and Victoria, the bloodspot cards are currently stored indefinitely.

  • Phenylketonuria (PKU) - 1 in 10,000 live births (about 10 babies per year). PKU causes high blood levels of phenylalanine and severe intellectual disability. A diet low in phenylalanine, started in the first two to three weeks results in normal development.
  • Primary congenital hypothyroidism - 1 in 3,500 live births (about 26 babies per year). It is caused by the absence or abnormal formation or function of the thyroid gland. This causes growth and intellectual disability if not treated. Medication with thyroid hormone started early, results in normal growth and development.
  • Cystic Fibrosis (CF) - 1 in 2,500 live births (about 34 babies per year). Without treatment babies develop chest infections and often have very serious failure to thrive. Early institution of treatment greatly improves the health of babies with CF. Newborn bloodspot screening detects about 95% of babies with CF but also detects a few babies who may only be healthy carriers. For these babies a sweat test at about six weeks of age determines whether the baby has CF or is a healthy carrier.
  • Galactosaemia - 1 in 40,000 births (about 1-3 cases per year). Babies cannot process galactose, a component of lactose. Life-threatening liver failure and infections can occur. A galactose-free diet instituted in the first week is life saving.
  • Rarer metabolic disorders - Some fatty acid, organic acid and other amino acid defects can now be detected using Tandem Mass Spectrometry. These much rarer metabolic disorders affect about 15 – 18 babies per year. Early detection is important as diet and medications can treat most of these disorders. Without appropriate management they can cause severe disability or death.

Genetics services in NSW - coordinated by the NSW Genetics Service Advisory Committee, which is supported by the Statewide Services Development Branch of the Strategic Development Division, NSW Department of Health. (Information from NSW Health - Newborn Bloodspot Screening Policy 13-Nov-2006)


neonatal diagnosis | NSW Genetics Health

Science Student Projects 2011

The links below are to pages prepared as part of an undergraduate science student projects carried out in the Embryology course. Please note these are student submissions and may include inaccuracies in either description or understanding.

2011 Projects: Turner Syndrome | DiGeorge Syndrome | Klinefelter's Syndrome | Huntington's Disease | Fragile X Syndrome | Tetralogy of Fallot | Angelman Syndrome | Friedreich's Ataxia | Williams-Beuren Syndrome | Duchenne Muscular Dystrolphy | Cleft Palate and Lip


International Classification of Diseases

The International Classification of Diseases (ICD) World Health Organization's classification used worldwide as the standard diagnostic tool for epidemiology, health management and clinical purposes. This includes the analysis of the general health situation of population groups. It is used to monitor the incidence and prevalence of diseases and other health problems. Within this classification "congenital malformations, deformations and chromosomal abnormalities" are (Q00-Q99) but excludes "inborn errors of metabolism" (E70-E90).

Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

  • Q90 Down's syndrome
    • Q90.0 Trisomy 21, meiotic nondisjunction
    • Q90.1 Trisomy 21, mosaicism (mitotic nondisjunction)
    • Q90.2 Trisomy 21, translocation
    • Q90.9 Down's syndrome, unspecified Trisomy 21 NOS
  • Q91 Edwards' syndrome and Patau's syndrome
    • Q91.0 Trisomy 18, meiotic nondisjunction
    • Q91.1 Trisomy 18, mosaicism (mitotic nondisjunction)
    • Q91.2 Trisomy 18, translocation
    • Q91.3 Edwards' syndrome, unspecified
    • Q91.4 Trisomy 13, meiotic nondisjunction
    • Q91.5 Trisomy 13, mosaicism (mitotic nondisjunction)
    • Q91.6 Trisomy 13, translocation
    • Q91.7 Patau's syndrome, unspecified
  • Q92 Other trisomies and partial trisomies of the autosomes, not elsewhere classified Incl.: unbalanced translocations and insertions Excl.: trisomies of chromosomes 13, 18, 21 (Q90-Q91)
    • Q92.0 Whole chromosome trisomy, meiotic nondisjunction
    • Q92.1 Whole chromosome trisomy, mosaicism (mitotic nondisjunction)
    • Q92.2 Major partial trisomy Whole arm or more duplicated.
    • Q92.3 Minor partial trisomy Less than whole arm duplicated.
    • Q92.4 Duplications seen only at prometaphase
    • Q92.5 Duplications with other complex rearrangements
    • Q92.6 Extra marker chromosomes
    • Q92.7 Triploidy and polyploidy
    • Q92.8 Other specified trisomies and partial trisomies of autosomes
    • Q92.9 Trisomy and partial trisomy of autosomes, unspecified
  • Q93 Monosomies and deletions from the autosomes, not elsewhere classified
    • Q93.0 Whole chromosome monosomy, meiotic nondisjunction
    • Q93.1 Whole chromosome monosomy, mosaicism (mitotic nondisjunction)
    • Q93.2 Chromosome replaced with ring or dicentric
    • Q93.3 Deletion of short arm of chromosome 4 Wolff-Hirschorn syndrome
    • Q93.4 Deletion of short arm of chromosome 5 Cri-du-chat syndrome
    • Q93.5 Other deletions of part of a chromosome Angelman syndrome
    • Q93.6 Deletions seen only at prometaphase
    • Q93.7 Deletions with other complex rearrangements
    • Q93.8 Other deletions from the autosomes
    • Q93.9 Deletion from autosomes, unspecified
  • Q95 Balanced rearrangements and structural markers, not elsewhere classified Incl.: Robertsonian and balanced reciprocal translocations and insertions
    • Q95.0 Balanced translocation and insertion in normal individual
    • Q95.1 Chromosome inversion in normal individual
    • Q95.2 Balanced autosomal rearrangement in abnormal individual
    • Q95.3 Balanced sex/autosomal rearrangement in abnormal individual
    • Q95.4 Individuals with marker heterochromatin
    • Q95.5 Individuals with autosomal fragile site
    • Q95.8 Other balanced rearrangements and structural markers
    • Q95.9 Balanced rearrangement and structural marker, unspecified
  • Q96 Turner's syndrome Excl.: Noonan's syndrome (Q87.1)
    • Q96.0 Karyotype 45,X
    • Q96.1 Karyotype 46,X iso (XQ)
    • Q96.2 Karyotype 46,X with abnormal sex chromosome, except iso (XQ)
    • Q96.3 Mosaicism, 45,X/46,XX or XY
    • Q96.4 Mosaicism, 45,X/other cell line(s) with abnormal sex chromosome
    • Q96.8 Other variants of Turner's syndrome
    • Q96.9 Turner's syndrome, unspecified
  • Q97 Other sex chromosome abnormalities, female phenotype, not elsewhere classified Excl.: Turner's syndrome (Q96.-)
    • Q97.0 Karyotype 47,XXX
    • Q97.1 Female with more than three X chromosomes
    • Q97.2 Mosaicism, lines with various numbers of X chromosomes
    • Q97.3 Female with 46,XY karyotype
    • Q97.8 Other specified sex chromosome abnormalities, female phenotype
    • Q97.9 Sex chromosome abnormality, female phenotype, unspecified
  • Q98 Other sex chromosome abnormalities, male phenotype, not elsewhere classified
    • Q98.0 Klinefelter's syndrome karyotype 47,XXY
    • Q98.1 Klinefelter's syndrome, male with more than two X chromosomes
    • Q98.2 Klinefelter's syndrome, male with 46,XX karyotype
    • Q98.3 Other male with 46,XX karyotype
    • Q98.4 Klinefelter's syndrome, unspecified
    • Q98.5 Karyotype 47,XYY
    • Q98.6 Male with structurally abnormal sex chromosome
    • Q98.7 Male with sex chromosome mosaicism
    • Q98.8 Other specified sex chromosome abnormalities, male phenotype
    • Q98.9 Sex chromosome abnormality, male phenotype, unspecified
  • Q99 Other chromosome abnormalities, not elsewhere classified
    • Q99.0 Chimera 46,XX/46,XY Chimera 46,XX/46,XY true hermaphrodite
    • Q99.1 46,XX true hermaphrodite 46,XX with streak gonads 46,XY with streak gonads Pure gonadal dysgenesis
    • Q99.2 Fragile X chromosome Fragile X syndrome
    • Q99.8 Other specified chromosome abnormalities
    • Q99.9 Chromosomal abnormality, unspecified


ICD-10 Code: Chromosomal abnormalities, not elsewhere classified

References

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  13. 13.0 13.1 Harper JC, Aittomäki K, Borry P, Cornel MC, de Wert G, Dondorp W, Geraedts J, Gianaroli L, Ketterson K, Liebaers I, Lundin K, Mertes H, Morris M, Pennings G, Sermon K, Spits C, Soini S, van Montfoort APA, Veiga A, Vermeesch JR, Viville S & Macek M. (2018). Recent developments in genetics and medically assisted reproduction: from research to clinical applications. Eur. J. Hum. Genet. , 26, 12-33. PMID: 29199274 DOI.
  14. Hook EB. (1981). Rates of chromosome abnormalities at different maternal ages. Obstet Gynecol , 58, 282-5. PMID: 6455611
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  17. GUTHRIE R & SUSI A. (1963). A SIMPLE PHENYLALANINE METHOD FOR DETECTING PHENYLKETONURIA IN LARGE POPULATIONS OF NEWBORN INFANTS. Pediatrics , 32, 338-43. PMID: 14063511

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Terms

  • anaphase - (Greek, ana = up, again) Cell division term referring to the fourth mitotic stage, where the paired chromatids now separate and migrate to spindle poles. This is followed by telophase.
Mitosis Phases: prophase - prometaphase - metaphase - anaphase - telophase
  • anaphase B - Cell division term referring to the part of anaphase during which the poles of the mitotic spindle move apart. (More? Cell Division - Mitosis)
  • aneuploidy - Genetic term used to describe an abnormal number of chromosomes mainly (90%) due to chromosome malsegregation mechanisms in maternal meiosis I.
  • disomy - Genetic term referring to the presence of two chromosomes of a homologous pair in a cell, as in diploid. See chromosomal number genetic disorders uniparental disomy and aneuploidy. Humans have pairs usually formed by one chromosome from each parent.
  • meiosis I (MI) The first part of meiosis resulting in separation of homologous chromosomes, in humans producing two haploid cells (N chromosomes, 23), a reductional division.
Meiosis I: Prophase I - Metaphase I - Anaphase I - Telophase I
  • meiosis II - (MII) The second part of meiosis. In male human spermatogenesis, producing of four haploid cells (23 chromosomes, 1N) from the two haploid cells (23 chromosomes, 1N), each of the chromosomes consisting of two sister chromatids produced in meiosis I. In female human oogenesis, only a single haploid cell (23 chromosomes, 1N) is produced.
Meiosis II: Prophase II - Metaphase II - Anaphase II - Telophase II
  • prometaphase - (Greek, pro = before) Cell division term referring to the second mitotic stage, when the nuclear envelope breaks down into vesicles. Microtubules then extend from the centrosomes at the spindle poles (ends) and reach the chromosomes. This is followed by metaphase.
  • Philadelphia chromosome - (Philadelphia translocation) Genetic term referring to a chromosomal abnormality resulting from a reciprocal translocation between chromosome 9 and 22 (t(9;22)(q34;q11)). This is associated with the disease chronic myelogenous leukemia (CML).
  • prophase - (Greek, pro = before) Cell division term referring to the first mitotic stage, when the diffusely stained chromatin resolves into discrete chromosomes, each consisting of two chromatids joined together at the centromere.
  • telophase - Cell division term referring to the fifth mitotic stage, where the vesicles of the nuclear envelope reform around the daughter cells, the nucleoli reappear and the chromosomes unfold to allow gene expression to begin. This phase overlaps with cytokinesis, the division of the cell cytoplasm.
  • trisomy mosaicism - a rare chromosome disorder characterized by having an extra copy of a chromosome in a proportion, but not all, of a person’s cells.
  • uniparental disomy - Genetic term referring to cells containing both copies of a homologous pair of chromosomes from one parent and none from the other parent.


Cell Division Terms (expand to view) 
meiosis | mitosis
  • anaphase - (Greek, ana = up, again) Mitosis term referring to the fourth stage, where the paired chromatids now separate and migrate to spindle poles. This is followed by telophase.
  • anaphase A - Mitosis term referring to the part of anaphase during which the chromosomes move.
  • anaphase B - Mitosis term referring to the part of anaphase during which the poles of the mitotic spindle move apart.
  • aneuploidy - (aneuploid) term used to describe an abnormal number of chromosomes mainly (90%) due to chromosome malsegregation mechanisms in maternal meiosis I.
  • aster - (Latin, aster = star) star-like object visible in most dividing eukaryotic cells contains the microtubule organizing center.
  • astral microtubule - spindle apparatus microtubule (MT) originating from the centrosome which does not connect to a kinetochore. These microtubules only exist during mitosis, the other spindle types are polar and kinetochore microtubules.
  • autosomal inheritance - term used in hereditary diseases which means that the disease is due to a DNA error in one of the 22 chromosome pairs that are not sex chromosomes. Both boys and girls can then inherit this error. If the error is in a sex chromosome, the inheritance is said to be sex-linked.
  • bivalent - (tetrad) a pair of homologous chromosomes physically held together by at least one DNA crossover.
  • bouquet stage - meiosis term for when in prophase transition to the zygotene stage, the chromosome telomeres attachment to the inner nuclear envelope and form a cluster. This occurs before the onset of homologous pairing and synapsis. The name comes from the chromosomes resembling a "bouquet of flowers".
  • diploid - (Greek, di = double + ploion = vessel) having two sets of chromosomes (2n), this is the normal euploidy state for all human cells, other than gametes that are haploid (n, a single set of chromosomes).
  • diplotene stage- (diplotene phase, diplonema; Greek, diplonema = "two threads") meiotic stage seen during prophase I, the chromosomes separate from one another a small amount giving this appearance. In the developing human ovary, oocytes remain at the diplotene stage from fetal life through postnatal childhood, until puberty when the lutenizing hormone (LH) surges stimulate the resumption of meiosis. Prophase I, is divided into 5 stages (leptotene, zygotene, pachytene, diplotene, diakinesis) based upon changes associated with the synaptonemal complex structure that forms between two pairs of homologous chromosomes.
  • euploidy - the normal genome chromosomal set (n, 2n, 3n) or complement for a species, in humans this is diploid (2n). The other classes of numerical chromosomal abnormalities include aneuploidy, polyploidy and mixoploidy.
  • FUCCI - Acronym for Fluorescence Ubiquitination Cell Cycle Indicator a molecular tool for identifying the stage in the cell cycle. In G0/G1 cells express a red fluorescent protein and S/G2/M cells express a green fluorescent protein. (More? Tooth Development Movie)
  • haploid - (Greek, haploos = single) Having a single set of chromosomes (n) as in mature germ/sex cells (oocyte, spermatozoa) following reductive cell division by meiosis. Normally cells are diploid, containing 2 sets of chromosomes. Ploidy refers to the number of sets of chromosomes in the nucleus of a cell.
  • heteroplasmy - presence of more than one type of organellar genome. In humans this can refer to variations in the mitochondrial DNA (mtDNA). (More? PMID 26281784)
  • homologous chromosomes - meiosis term for the two matching (maternal and one paternal) chromosomes that align during meiosis I.
  • homologous recombination - meiosis term when DNA of homologous chromosomes is covalently exchanged to produce chromosomes with new allele combinations, and also links homologous chromosomes with each other to form a bivalent
  • human genome - DNA within the 23 nucleus chromosome pairs and the cytoplasmic mitochondrial DNA.
  • kinetochore - the protein structure formed on chromatids where the spindle kinetochore microtubules attach during cell division.
  • kinetochore microtubule - spindle apparatus microtubule (MT) that attaches to the chromosome kinetochore by its plus end, the other spindle types are astral and polar microtubules.
  • kinesin - a microtubule (MT) motor protein that exists in many isoforms and most move towards the MT positive end. Different isoforms have different functions within the spindle apparatus. PMID 20109570
  • meiosis - reductive cell division required to produce germ cells (oocyte, spermatozoa) and for sexual reproduction. Note that only spermatozoa complete meiosis before fertilisation. Chromosome number is reduced from diploid to haploid, during this process maternal and paternal genetic material are exchanged. All other non-germ cells in the body divide by mitosis. (More? Meiosis | Spermatozoa Development | Oocyte Development | Week 1)
  • meiosis I - (MI) the first part of meiosis resulting in separation of homologous chromosomes, in humans producing two haploid cells (N chromosomes, 23), a reductional division.
  • meiosis II - (MII) the second part of meiosis. In male human spermatogenesis, producing of four haploid cells (23 chromosomes, 1N) from the two haploid cells (23 chromosomes, 1N), each of the chromosomes consisting of two sister chromatids produced in meiosis I. In female human oogenesis, only a single haploid cell (23 chromosomes, 1N) is produced. Meiosis II: Prophase II - Metaphase II - Anaphase II - Telophase II.
  • meiotic silencing of unsynapsed chromatin - (MSUC) an aneuploidy protective mechanism for subsequent generations, during meiosis where chromosomes are silenced that fail to pair with their homologous partners.
  • merotelic kinetochore - cell division abnormality in chromosomal attachment that occurs when a single kinetochore is attached to microtubules arising from both spindle poles. Normal chromosomal attachment in early mitosis, is by only one of the two sister kinetochores attached to spindle microtubules (monotelic attachment) later sister kinetochores attach to microtubules arising from opposite spindle poles (amphitelic attachment).
  • metaphase - mitosis term referring to the third stage where mitotic spindle kinetochore microtubules align chromosomes in one midpoint plane. Metaphase ends when sister kinetochores separate. Originally based on light microscopy of living cells and electron microscopy of fixed and stained cells. A light microscope analysis called a "metaphase spread" was originally used to detect chromosomal abnormalities in cells. Mitosis Phases: prophase - prometaphase - metaphase - anaphase - telophase
  • metaphase spread - In mitosis using light microscope analysis originally used to detect chromosomal abnormalities in cells, as chromosomes are only visible during cell division.
  • microfilament - (MF) cytoskeleton filament normally required for cytoplasmic intracellular transport, motility and cell shape. Named by the actin monomers assembling into the smallest in cross-section of the three filament systems (microtubules and intermediate filaments). This system is disassembled and reassembled as the contractile ring for cytokinesis (cytoplasm division) following cell division mitosis and meiosis.
  • microtubule - (MT) cytoskeleton filament normally required for cytoplasmic intracellular transport and motility. Named by the tubulin monomers assembling into "tubes", and are the largest in cross-section of the three filament systems (microfilaments and intermediate filaments). This system is disassembled and reassembled as the spindle apparatus during cell division.
  • mitochondrial DNA - (mtDNA) multiple copies of a small circular DNA molecule located within the mitochondria matrix. In humans 16,568 bp in length containing 37 genes, originally inherited only from the oocyte (maternal inheritance).
  • mitosis - (M phase) The normal division of all cells, except germ cells, where chromosome number is maintained (diploid). In germ cell division (oocyte, spermatozoa) meiosis is a modified form of this division resulting in reduction in genetic content (haploid). Mitosis, division of the nucleus, is followed by cytokinesis the division of the cell cytoplasm and the cytoplasmic contents. cytokinesis overlaps with telophase.
  • p - chromosome short arm (possibly French, petit) and used along with chromosome and band number to indicate genes located on this arm of the chromosome. The chromosome long arm is identified as q (possibly French, tall) chosen as next letter in alphabet after p. These chromosomal arms are only seen when the chromosome is folded for cell division.
  • polar microtubule - spindle apparatus microtubule (MT) that can arise from either pole and overlap at the spindle midzone. This interdigitating structure consisting of antiparallel microtubules is responsible for pushing the poles of the spindle apart. The other spindle types are astral and kinetochore microtubules.
  • prometaphase - (Greek, pro = before) mitosis term referring to the second stage, when the nuclear envelope breaks down into vesicles. Microtubules then extend from the centrosomes at the spindle poles (ends) and reach the chromosomes. This is followed by metaphase.
  • pronuclear fusion - (Greek, pro = before) the process of the fusion of the two haploid nuclear structures (pronuclei) contributed from the spermatazoa and oocyte to form the first diploid nucleus cell. Can also be called "fusion of pronuclei".
  • pronucleus - (Greek, pro = before; plural, pronuclei) the two haploid nuclei or nuclear structures containing the genetic material from the spermatozoa and the oocyte. These two haploid nuclei will fuse together to form the first diploid nucleus cell, the zygote. Therefore the nuclear structures that exist "before the nucleus", the plural term is pronuclei.
  • prophase - (Greek, pro = before) - mitosis term referring to the first stage, when the diffusely stained chromatin resolves into discrete chromosomes, each consisting of two chromatids joined together at the centromere.
  • prophase I - meiosis term refers to the first phase of meiosis I, which together with meiosis II results in the reductive cell division only occurring gametes. Prophase can be further divided into a number of stages: leptotene zygotene, pachytene, diplotene, diakinesis.
  • q - chromosome long arm (possibly French, tall), the next letter in alphabet after p, and used along with chromosome and band number to indicate genes located on this arm of the chromosome. The chromosome short arm is identified as p (possibly French, petit). These chromosomal arms are only seen when the chromosome is folded for cell division.
  • S phase - during interphase of cell cycle where DNA is duplicated prior to second growth period (G2 phase) that is followed by mitosis (M phase).
  • synapsis - (syndesis) meiosis term for the pairing of two homologous chromosomes that occurs during prophase I.
  • synaptonemal complex - meiosis term for a protein structure essential for synapsis of homologous chromosomes. (proteins SCP3 and SCP1).
  • telomere - region found at each end of the chromosome and involved in cellular ageing and the capacity for division. The regions consist of repeated sequences protecting the ends of chromosomes and harbour DNA repair proteins. In the absence of the enzyme telomerase, these regions shorten during each cell division and becoming critically short, cell senescence occurs.
  • telophase - mitosis term referring to the fifth stage, where the vesicles of the nuclear envelope reform around the daughter cells, the nucleoli reappear and the chromosomes unfold to allow gene expression to begin. This phase overlaps with cytokinesis, the division of the cell cytoplasm.
  • telomerase - the enzyme that maintains the chromosome end length, the telomeres, involved in cellular ageing and the capacity for division. Absence of telomerase activity leads to the chromosome ends shorten during each cell division, becoming critically short and cell senescence then occurs.
  • tetrad - (bivalent) a pair of homologous chromosomes physically held together by at least one DNA crossover.
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Cite this page: Hill, M.A. (2024, March 28) Embryology Abnormal Development - Genetic. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Abnormal_Development_-_Genetic

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