Preimplantation Genetic Diagnosis - Revision history

Z8600021 at 00:35, 7 August 2019

2019-08-07T00:35:16Z

← Older revision		Revision as of 11:35, 7 August 2019
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	==Introduction==		==Introduction==
	[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]		[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]
	This current page is a general starting point for the topic of Preimplantation Genetic Screening (PGS) also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to other forms of prenatal diagnosis.		This current page is a general starting point for the topic of Preimplantation Genetic Screening (PGS, {{NIPT}}) also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to other forms of prenatal diagnosis.


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			* '''Noninvasive preimplantation genetic testing for aneuploidy in spent medium may be more reliable than trophectoderm biopsy'''{{#pmid:31235575\|PMID31235575}} "Preimplantation genetic testing for aneuploidy (PGT-A) with trophectoderm (TE) biopsy is widely applied in in vitro fertilization (IVF) to identify aneuploid embryos. However, potential safety concerns regarding biopsy and restrictions to only those embryos suitable for biopsy pose limitations. In addition, embryo mosaicism gives rise to false positives and false negatives in PGT-A because the inner cell mass (ICM) cells, which give rise to the fetus, are not tested. Here, we report a critical examination of the efficacy of noninvasive preimplantation genetic testing for aneuploidy (niPGT-A) in the spent culture media of human blastocysts by analyzing the cell-free DNA, which reflects ploidy of both the TE and ICM. Fifty-two frozen donated blastocysts with TE biopsy results were thawed; each of their spent culture medium was collected after 24-h culture and analyzed by next-generation sequencing (NGS). niPGT-A and TE-biopsy PGT-A results were compared with the sequencing results of the corresponding embryos, which were taken as true results for aneuploidy reporting. With removal of all corona-cumulus cells, the false-negative rate (FNR) for niPGT-A was found to be zero. By applying an appropriate threshold for mosaicism, both the positive predictive value (PPV) and specificity for niPGT-A were much higher than TE-biopsy PGT-A. Furthermore, the concordance rates for both embryo ploidy and chromosome copy numbers were higher for niPGT-A than TE-biopsy PGT-A. These results suggest that niPGT-A is less prone to errors associated with embryo mosaicism and is more reliable than TE-biopsy PGT-A."

	* '''Euploidy in relation to blastocyst sex and morphology'''{{#pmid:30030712\|PMID30030712}} "This is a retrospective cohort study at an academic medical center of patients who underwent in vitro fertilization with preimplantation genetic screening (PGS) from 2010 to 2015. Embryos were screened with 24-chromosome preimplantation genetic screening with day 5/6 trophectoderm biopsy. We investigated embryo euploidy in relation to morphology (expansion, inner cell mass, trophectoderm), embryo sex, biopsy day, and blastocyst cohort size. We used multivariate logistic regression to calculate odds ratios of euploidy in relation to these parameters. RESULTS: A total of 1559 embryos from 316 cycles and 233 patients (mean maternal age = 37.8 ± 4.2 years) were included in the analysis. Six hundred and twenty-eight blastocysts (40.3%) were found to be euploid. Expansion (p < 0.001), inner cell mass (ICM) (p < 0.01), and trophectoderm grade (p < 0.001) were significantly associated with embryo ploidy in bivariate models controlling for maternal age, while embryo sex, biopsy day, and blastocyst cohort size were not associated with embryo ploidy. In a multivariate model, we found that maternal age (p < 0.001), higher grade of expansion (p < 0.01), and better quality trophectoderm (p < 0.001 for A compared to C grade) remained significantly associated with increased embryo euploidy, but ICM grade was no longer significant. Embryo sex was not associated with ploidy status, though male embryos were found to be associated with higher trophectoderm scores (p < 0.02). CONCLUSIONS: This is the largest study to date to investigate PGS-tested embryo sex and ploidy status. While maternal age and some morphological parameters (expansion, trophectoderm grade) are associated with euploidy in our cohort, other parameters such as embryo sex, biopsy day, and cohort size are not. Though embryo sex was not associated with euploidy, male embryos were found to be associated with higher trophectoderm grades. Additional investigation in larger studies is warranted."		* '''Euploidy in relation to blastocyst sex and morphology'''{{#pmid:30030712\|PMID30030712}} "This is a retrospective cohort study at an academic medical center of patients who underwent in vitro fertilization with preimplantation genetic screening (PGS) from 2010 to 2015. Embryos were screened with 24-chromosome preimplantation genetic screening with day 5/6 trophectoderm biopsy. We investigated embryo euploidy in relation to morphology (expansion, inner cell mass, trophectoderm), embryo sex, biopsy day, and blastocyst cohort size. We used multivariate logistic regression to calculate odds ratios of euploidy in relation to these parameters. RESULTS: A total of 1559 embryos from 316 cycles and 233 patients (mean maternal age = 37.8 ± 4.2 years) were included in the analysis. Six hundred and twenty-eight blastocysts (40.3%) were found to be euploid. Expansion (p < 0.001), inner cell mass (ICM) (p < 0.01), and trophectoderm grade (p < 0.001) were significantly associated with embryo ploidy in bivariate models controlling for maternal age, while embryo sex, biopsy day, and blastocyst cohort size were not associated with embryo ploidy. In a multivariate model, we found that maternal age (p < 0.001), higher grade of expansion (p < 0.01), and better quality trophectoderm (p < 0.001 for A compared to C grade) remained significantly associated with increased embryo euploidy, but ICM grade was no longer significant. Embryo sex was not associated with ploidy status, though male embryos were found to be associated with higher trophectoderm scores (p < 0.02). CONCLUSIONS: This is the largest study to date to investigate PGS-tested embryo sex and ploidy status. While maternal age and some morphological parameters (expansion, trophectoderm grade) are associated with euploidy in our cohort, other parameters such as embryo sex, biopsy day, and cohort size are not. Though embryo sex was not associated with euploidy, male embryos were found to be associated with higher trophectoderm grades. Additional investigation in larger studies is warranted."

Z8600021 at 03:51, 23 July 2018

2018-07-23T03:51:11Z

← Older revision		Revision as of 14:51, 23 July 2018
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	==Introduction==		==Introduction==
	[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]		[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]
	This current page is a general starting point for the topic of Preimplantation Genetic Screening also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to prenatal diagnosis.		This current page is a general starting point for the topic of Preimplantation Genetic Screening (PGS) also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to other forms of prenatal diagnosis.


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	* '''The first successful application of preimplantation genetic diagnosis for hearing loss in Iran'''{{#pmid:30030956\|PMID30030956}} "Hearing impairment (HI) caused by mutations in the connexin-26 gene (GJB2) accounts for the majority of cases with inherited, nonsyndromic sensorineural hearing loss. Due to the illegality of the abortion of deaf fetuses in Islamic countries, preimplantation genetic diagnosis (PGD) is a possible solution for afflicted families to have a healthy offspring. This study describes the first use of PGD for GJB2 associated non-syndromic deafness in Iran. GJB2 donor splicing site IVS1+1G>A mutation analysis was performed using Sanger sequencing for a total of 71 Iranian families with at least 1 deaf child diagnosed with non-syndromic deafness. In Vitro Fertilization (IVF) was performed, followed by PGD for a cousin couple with a 50% chance of having an affected child. Bi-allelic pathogenic mutations were found in a total of 12 families (~17 %); of which a couple was a PGD volunteer. The deaf woman in this family was homozygous and her husband was a carrier of the IVS1+1G>A gene mutation. Among 8 biopsied embryos, two healthy embryos were implanted which resulted in a single pregnancy and subsequent birth of a healthy baby boy. This is the first report of a successful application of PGD for hearing loss in Iran." {{hearing}}		* '''The first successful application of preimplantation genetic diagnosis for hearing loss in Iran'''{{#pmid:30030956\|PMID30030956}} "Hearing impairment (HI) caused by mutations in the connexin-26 gene (GJB2) accounts for the majority of cases with inherited, nonsyndromic sensorineural hearing loss. Due to the illegality of the abortion of deaf fetuses in Islamic countries, preimplantation genetic diagnosis (PGD) is a possible solution for afflicted families to have a healthy offspring. This study describes the first use of PGD for GJB2 associated non-syndromic deafness in Iran. GJB2 donor splicing site IVS1+1G>A mutation analysis was performed using Sanger sequencing for a total of 71 Iranian families with at least 1 deaf child diagnosed with non-syndromic deafness. In Vitro Fertilization (IVF) was performed, followed by PGD for a cousin couple with a 50% chance of having an affected child. Bi-allelic pathogenic mutations were found in a total of 12 families (~17 %); of which a couple was a PGD volunteer. The deaf woman in this family was homozygous and her husband was a carrier of the IVS1+1G>A gene mutation. Among 8 biopsied embryos, two healthy embryos were implanted which resulted in a single pregnancy and subsequent birth of a healthy baby boy. This is the first report of a successful application of PGD for hearing loss in Iran." {{hearing}}

	* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."
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			* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."

	* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''{{#pmid:24628895\|PMID24628895}} "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."		* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''{{#pmid:24628895\|PMID24628895}} "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."

Z8600021 at 03:49, 23 July 2018

2018-07-23T03:49:47Z

← Older revision		Revision as of 14:49, 23 July 2018
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			* '''Euploidy in relation to blastocyst sex and morphology'''{{#pmid:30030712\|PMID30030712}} "This is a retrospective cohort study at an academic medical center of patients who underwent in vitro fertilization with preimplantation genetic screening (PGS) from 2010 to 2015. Embryos were screened with 24-chromosome preimplantation genetic screening with day 5/6 trophectoderm biopsy. We investigated embryo euploidy in relation to morphology (expansion, inner cell mass, trophectoderm), embryo sex, biopsy day, and blastocyst cohort size. We used multivariate logistic regression to calculate odds ratios of euploidy in relation to these parameters. RESULTS: A total of 1559 embryos from 316 cycles and 233 patients (mean maternal age = 37.8 ± 4.2 years) were included in the analysis. Six hundred and twenty-eight blastocysts (40.3%) were found to be euploid. Expansion (p < 0.001), inner cell mass (ICM) (p < 0.01), and trophectoderm grade (p < 0.001) were significantly associated with embryo ploidy in bivariate models controlling for maternal age, while embryo sex, biopsy day, and blastocyst cohort size were not associated with embryo ploidy. In a multivariate model, we found that maternal age (p < 0.001), higher grade of expansion (p < 0.01), and better quality trophectoderm (p < 0.001 for A compared to C grade) remained significantly associated with increased embryo euploidy, but ICM grade was no longer significant. Embryo sex was not associated with ploidy status, though male embryos were found to be associated with higher trophectoderm scores (p < 0.02). CONCLUSIONS: This is the largest study to date to investigate PGS-tested embryo sex and ploidy status. While maternal age and some morphological parameters (expansion, trophectoderm grade) are associated with euploidy in our cohort, other parameters such as embryo sex, biopsy day, and cohort size are not. Though embryo sex was not associated with euploidy, male embryos were found to be associated with higher trophectoderm grades. Additional investigation in larger studies is warranted."

	* '''Review - patient decision-making factors and attitudes regarding preimplantation genetic diagnosis'''{{#pmid:29120067\|PMID29120067}} "The increasing technical complexity and evolving options for repro-genetic testing have direct implications for information processing and decision making, yet the research among patients considering preimplantation genetic diagnosis (PGD) is narrowly focused. This review synthesizes the literature regarding patient PGD decision-making factors, and illuminates gaps for future research and clinical translation. Twenty-five articles met the inclusion criteria for evaluating experiences and attitudes of patients directly involved in PGD as an intervention or considering using PGD. Thirteen reports were focused exclusively on a specific disease or condition. Five themes emerged: (1) patients motivated by prospects of a healthy, genetic-variant-free child, (2) PGD requires a commitment of time, money, energy and emotions, (3) patients concerned about logistics and ethics of discarding embryos, (4) some patients feel sense of responsibility to use available technologies, and (5) PGD decisions are complex for individuals and couples. Patient research on PGD decision-making processes has very infrequently used validated instruments, and the data collected through both quantitative and qualitative designs have been inconsistent."		* '''Review - patient decision-making factors and attitudes regarding preimplantation genetic diagnosis'''{{#pmid:29120067\|PMID29120067}} "The increasing technical complexity and evolving options for repro-genetic testing have direct implications for information processing and decision making, yet the research among patients considering preimplantation genetic diagnosis (PGD) is narrowly focused. This review synthesizes the literature regarding patient PGD decision-making factors, and illuminates gaps for future research and clinical translation. Twenty-five articles met the inclusion criteria for evaluating experiences and attitudes of patients directly involved in PGD as an intervention or considering using PGD. Thirteen reports were focused exclusively on a specific disease or condition. Five themes emerged: (1) patients motivated by prospects of a healthy, genetic-variant-free child, (2) PGD requires a commitment of time, money, energy and emotions, (3) patients concerned about logistics and ethics of discarding embryos, (4) some patients feel sense of responsibility to use available technologies, and (5) PGD decisions are complex for individuals and couples. Patient research on PGD decision-making processes has very infrequently used validated instruments, and the data collected through both quantitative and qualitative designs have been inconsistent."

Z8600021 at 00:54, 23 July 2018

2018-07-23T00:54:42Z

← Older revision		Revision as of 11:54, 23 July 2018
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			* '''Review - patient decision-making factors and attitudes regarding preimplantation genetic diagnosis'''{{#pmid:29120067\|PMID29120067}} "The increasing technical complexity and evolving options for repro-genetic testing have direct implications for information processing and decision making, yet the research among patients considering preimplantation genetic diagnosis (PGD) is narrowly focused. This review synthesizes the literature regarding patient PGD decision-making factors, and illuminates gaps for future research and clinical translation. Twenty-five articles met the inclusion criteria for evaluating experiences and attitudes of patients directly involved in PGD as an intervention or considering using PGD. Thirteen reports were focused exclusively on a specific disease or condition. Five themes emerged: (1) patients motivated by prospects of a healthy, genetic-variant-free child, (2) PGD requires a commitment of time, money, energy and emotions, (3) patients concerned about logistics and ethics of discarding embryos, (4) some patients feel sense of responsibility to use available technologies, and (5) PGD decisions are complex for individuals and couples. Patient research on PGD decision-making processes has very infrequently used validated instruments, and the data collected through both quantitative and qualitative designs have been inconsistent."

	* '''Preimplantation genetic diagnosis as a strategy to prevent having a child born with an heritable eye disease'''{{#pmid:29781739\|PMID29781739}} "In developed countries, genetically inherited eye diseases are responsible for a high percentage of childhood visual impairment. We aim to report our experience using preimplantation genetic diagnostics (PGD) in order to avoid transmitting a genetic form of eye disease associated with childhood visual impairment and ocular cancer. MATERIAL AND METHODS: Retrospective case series of women who underwent in vitro fertilization (IVF) and PGD due to a familial history of inherited eye disease and/or ocular cancer, in order to avoid having a child affected with the known familial disease. Each family underwent genetic testing in order to identify the underlying disease-causing mutation. IVF and PGD treatment were performed; unaffected embryos were implanted in their respective mothers. RESULTS: Thirty-five unrelated mothers underwent PGD, and the following hereditary conditions were identified in their families: albinism (10 families); retinitis pigmentosa (7 families); retinoblastoma (4 families); blue cone monochromatism, achromatopsia, and aniridia (2 families each); and Hermansky-Pudlak syndrome, Leber congenital amaurosis, Norrie disease, papillorenal syndrome, primary congenital cataract, congenital glaucoma, Usher syndrome type 1F, and microphthalmia with coloboma (1 family each). Following a total of 88 PGD cycles, 18 healthy (i.e., unaffected) children were born." {{vision}}		* '''Preimplantation genetic diagnosis as a strategy to prevent having a child born with an heritable eye disease'''{{#pmid:29781739\|PMID29781739}} "In developed countries, genetically inherited eye diseases are responsible for a high percentage of childhood visual impairment. We aim to report our experience using preimplantation genetic diagnostics (PGD) in order to avoid transmitting a genetic form of eye disease associated with childhood visual impairment and ocular cancer. MATERIAL AND METHODS: Retrospective case series of women who underwent in vitro fertilization (IVF) and PGD due to a familial history of inherited eye disease and/or ocular cancer, in order to avoid having a child affected with the known familial disease. Each family underwent genetic testing in order to identify the underlying disease-causing mutation. IVF and PGD treatment were performed; unaffected embryos were implanted in their respective mothers. RESULTS: Thirty-five unrelated mothers underwent PGD, and the following hereditary conditions were identified in their families: albinism (10 families); retinitis pigmentosa (7 families); retinoblastoma (4 families); blue cone monochromatism, achromatopsia, and aniridia (2 families each); and Hermansky-Pudlak syndrome, Leber congenital amaurosis, Norrie disease, papillorenal syndrome, primary congenital cataract, congenital glaucoma, Usher syndrome type 1F, and microphthalmia with coloboma (1 family each). Following a total of 88 PGD cycles, 18 healthy (i.e., unaffected) children were born." {{vision}}

Z8600021 at 00:48, 23 July 2018

2018-07-23T00:48:26Z

← Older revision		Revision as of 11:48, 23 July 2018
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	:'''Links:''' [http://www.genetests.org/ GeneTests] \| [http://www.nlm.nih.gov/medlineplus/genetictesting.html Medline Plus - Genetic Testing]		:'''Links:''' [http://www.genetests.org/ GeneTests] \| [http://www.nlm.nih.gov/medlineplus/genetictesting.html Medline Plus - Genetic Testing]

			==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.

			<gallery>
			File:Autosomal_dominant_inheritance.jpg\|Autosomal dominant inheritance
			File:Autosomal recessive inheritance.jpg\|Autosomal recessive inheritance
			File:X-Linked_dominant_(affected_father).jpg\|X-Linked dominant (affected father)
			File:X-Linked_dominant_(affected_mother).jpg\|X-Linked dominant (affected mother)
			File:X-Linked_recessive_(affected_father).jpg\|X-Linked recessive (affected father)
			File:X-Linked recessive (carrier mother).jpg\|X-Linked recessive (carrier mother)
			File:Mitochondrial_inheritance.jpg\|Mitochondrial genome inheritance
			File:Codominant inheritance.jpg\|Codominant inheritance
			</gallery>

			{{GHR Inheritance}}

	==Ethics of Testing==		==Ethics of Testing==
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	<references/>		<references/>
	===Reviews===		===Reviews===
			{{#pmid:22216843}}

	~~<pubmed>22216843</pubmed>~~		{{#pmid:21743973}}
	~~<pubmed>~~21743973~~</pubmed>~~

	===Articles===		===Articles===
	~~<pubmed>~~21397558~~</pubmed>~~		{{#pmid:21397558}}
	~~<pubmed>~~20966462~~</pubmed>~~
	~~<pubmed>~~20966461~~</pubmed>~~		{{#pmid:20966462}}
	~~<pubmed>~~20966460~~</pubmed>~~
	~~<pubmed>~~20966459~~</pubmed>~~		{{#pmid:20966461}}

			{{#pmid:20966460}}

			{{#pmid:20966459}}

	===Journals===		===Journals===

Z8600021 at 00:42, 23 July 2018

2018-07-23T00:42:01Z

← Older revision		Revision as of 11:42, 23 July 2018
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	[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]		[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]
	This current page is a general starting point for the topic of Preimplantation Genetic Screening also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to prenatal diagnosis.		This current page is a general starting point for the topic of Preimplantation Genetic Screening also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to prenatal diagnosis.


			:"In the general population trisomies and sex chromosome aneuploidies account for approximately 70% of anomalies recognizable by conventional genetic analysis."{{#pmid:30001568\|PMID30001568}}


	Recently with the growth in [[Assisted Reproductive Technology]] (ART) or commonly known as In Vitro Fertilization (IVF), there is now a new form of prenatal diagnosis that involves genetic testing of the blastocyst before implantation. (More? [[Assisted Reproductive Technology]])		Recently with the growth in [[Assisted Reproductive Technology]] (ART) or commonly known as In Vitro Fertilization (IVF), there is now a new form of prenatal diagnosis that involves genetic testing of the blastocyst before implantation. (More? [[Assisted Reproductive Technology]])


	Generally, in vitro fertilised embryos are first cultured for up to three days. By this time the conceptus is composed of 6 to 10 cells (blastomeres) from which 1 or 2 cells are then removed by a laser for genetic testing. Some studies have also removed cells, or the polar body, at earlier days following fertilisation. While other studies have collected cells from later stage (day 5) blastocyst either the trophectoderm (trophoblast) or inner cell mass (embryoblast).		Generally, in vitro fertilised embryos are first cultured for up to three days. By this time the conceptus is composed of 6 to 10 cells (blastomeres) from which 1 or 2 cells are then removed by a laser for genetic testing. Some studies have also removed cells, or the polar body, at earlier days following fertilisation. While other studies have collected cells from later stage (day 5) blastocyst either the trophectoderm (trophoblast) or inner cell mass (embryoblast).

Z8600021 at 00:27, 23 July 2018

2018-07-23T00:27:29Z

← Older revision		Revision as of 11:27, 23 July 2018
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			* '''Preimplantation genetic diagnosis as a strategy to prevent having a child born with an heritable eye disease'''{{#pmid:29781739\|PMID29781739}} "In developed countries, genetically inherited eye diseases are responsible for a high percentage of childhood visual impairment. We aim to report our experience using preimplantation genetic diagnostics (PGD) in order to avoid transmitting a genetic form of eye disease associated with childhood visual impairment and ocular cancer. MATERIAL AND METHODS: Retrospective case series of women who underwent in vitro fertilization (IVF) and PGD due to a familial history of inherited eye disease and/or ocular cancer, in order to avoid having a child affected with the known familial disease. Each family underwent genetic testing in order to identify the underlying disease-causing mutation. IVF and PGD treatment were performed; unaffected embryos were implanted in their respective mothers. RESULTS: Thirty-five unrelated mothers underwent PGD, and the following hereditary conditions were identified in their families: albinism (10 families); retinitis pigmentosa (7 families); retinoblastoma (4 families); blue cone monochromatism, achromatopsia, and aniridia (2 families each); and Hermansky-Pudlak syndrome, Leber congenital amaurosis, Norrie disease, papillorenal syndrome, primary congenital cataract, congenital glaucoma, Usher syndrome type 1F, and microphthalmia with coloboma (1 family each). Following a total of 88 PGD cycles, 18 healthy (i.e., unaffected) children were born." {{vision}}

			* '''The first successful application of preimplantation genetic diagnosis for hearing loss in Iran'''{{#pmid:30030956\|PMID30030956}} "Hearing impairment (HI) caused by mutations in the connexin-26 gene (GJB2) accounts for the majority of cases with inherited, nonsyndromic sensorineural hearing loss. Due to the illegality of the abortion of deaf fetuses in Islamic countries, preimplantation genetic diagnosis (PGD) is a possible solution for afflicted families to have a healthy offspring. This study describes the first use of PGD for GJB2 associated non-syndromic deafness in Iran. GJB2 donor splicing site IVS1+1G>A mutation analysis was performed using Sanger sequencing for a total of 71 Iranian families with at least 1 deaf child diagnosed with non-syndromic deafness. In Vitro Fertilization (IVF) was performed, followed by PGD for a cousin couple with a 50% chance of having an affected child. Bi-allelic pathogenic mutations were found in a total of 12 families (~17 %); of which a couple was a PGD volunteer. The deaf woman in this family was homozygous and her husband was a carrier of the IVS1+1G>A gene mutation. Among 8 biopsied embryos, two healthy embryos were implanted which resulted in a single pregnancy and subsequent birth of a healthy baby boy. This is the first report of a successful application of PGD for hearing loss in Iran." {{hearing}}

	* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."		* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."
	\|}		\|}

Z8600021 at 00:21, 23 July 2018

2018-07-23T00:21:34Z

← Older revision		Revision as of 11:21, 23 July 2018
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	\|		\|
	* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."		* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."
			\|}
			{\| class="wikitable mw-collapsible mw-collapsed"
			! More recent papers
			\|-
			\| [[File:Mark_Hill.jpg\|90px\|left]] {{Most_Recent_Refs}}

			Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=Preimplantation+Genetic+Diagnosis ''Preimplantation Genetic Diagnosis'']

			<pubmed limit=5>Preimplantation Genetic Diagnosis</pubmed>
			\|}

			{\| class="wikitable mw-collapsible mw-collapsed"
			! Older papers
			\|-
			\|
	* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''{{#pmid:24628895\|PMID24628895}} "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."		* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''{{#pmid:24628895\|PMID24628895}} "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."

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	* '''Preimplantation genetic diagnosis (PGD) for Huntington's disease: the experience of three European centres'''{{#pmid:22071896\|PMID22071896}} "This study provides an overview of 13 years of experience of preimplantation genetic diagnosis (PGD) for Huntington's disease (HD) at three European PGD centres in Brussels, Maastricht and Strasbourg. ... PGD workup was based on two approaches: (1) direct testing of the CAG-triplet repeat and (2) linkage analysis using intragenic or flanking microsatellite markers of the HTT gene. In total, 257 couples had started workup and 174 couples (70% direct testing, 30% exclusion testing) completed at least one PGD cycle. In total, 389 cycles continued to oocyte retrieval (OR). The delivery rates per OR were 19.8%, and per embryo transfer 24.8%, resulting in 77 deliveries and the birth of 90 children. We conclude that PGD is a valuable and safe reproductive option for HD carriers and couples at risk of transmitting HD."		* '''Preimplantation genetic diagnosis (PGD) for Huntington's disease: the experience of three European centres'''{{#pmid:22071896\|PMID22071896}} "This study provides an overview of 13 years of experience of preimplantation genetic diagnosis (PGD) for Huntington's disease (HD) at three European PGD centres in Brussels, Maastricht and Strasbourg. ... PGD workup was based on two approaches: (1) direct testing of the CAG-triplet repeat and (2) linkage analysis using intragenic or flanking microsatellite markers of the HTT gene. In total, 257 couples had started workup and 174 couples (70% direct testing, 30% exclusion testing) completed at least one PGD cycle. In total, 389 cycles continued to oocyte retrieval (OR). The delivery rates per OR were 19.8%, and per embryo transfer 24.8%, resulting in 77 deliveries and the birth of 90 children. We conclude that PGD is a valuable and safe reproductive option for HD carriers and couples at risk of transmitting HD."
	\|}		\|}

	==Genetic Testing==		==Genetic Testing==
	===Trisomy===		===Trisomy===

Z8600021 at 00:19, 23 July 2018

2018-07-23T00:19:19Z

← Older revision		Revision as of 11:19, 23 July 2018
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	==Introduction==		==Introduction==
	[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]		[[File:Human_embryo_day_3.jpg\|thumb\|200px\|Human Embryo (day 3)]][[File:Human_embryo_day_5.jpg\|thumb\|200px\|Human Embryo (day 5)]]
	This current page is a general starting point for the topic of Preimplantation Genetic Screening also called Preimplantation Genetic Diagnosis. Recently with the growth in [[Assisted Reproductive Technology]] (ART) or commonly known as In Vitro Fertilization (IVF), there is now a new form of prenatal diagnosis that involves genetic testing of the blastocyst before implantation. (More? [[Assisted Reproductive Technology]])		This current page is a general starting point for the topic of Preimplantation Genetic Screening also called Preimplantation Genetic Diagnosis (PGD) began during the 1990's as an alternative to prenatal diagnosis.


			Recently with the growth in [[Assisted Reproductive Technology]] (ART) or commonly known as In Vitro Fertilization (IVF), there is now a new form of prenatal diagnosis that involves genetic testing of the blastocyst before implantation. (More? [[Assisted Reproductive Technology]])

	Generally, in vitro fertilised embryos are first cultured for up to three days. By this time the conceptus is composed of 6 to 10 cells (blastomeres) from which 1 or 2 cells are then removed by a laser for genetic testing. Some studies have also removed cells, or the polar body, at earlier days following fertilisation. While other studies have collected cells from later stage (day 5) blastocyst either the trophectoderm (trophoblast) or inner cell mass (embryoblast).		Generally, in vitro fertilised embryos are first cultured for up to three days. By this time the conceptus is composed of 6 to 10 cells (blastomeres) from which 1 or 2 cells are then removed by a laser for genetic testing. Some studies have also removed cells, or the polar body, at earlier days following fertilisation. While other studies have collected cells from later stage (day 5) blastocyst either the trophectoderm (trophoblast) or inner cell mass (embryoblast).



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	{{Prenatal diagnosis}} \| [[Assisted Reproductive Technology]] \| [[In Vitro Fertilization]]		{{Prenatal diagnosis}} \| {{Assisted Reproductive Technology}} \| [[In Vitro Fertilization]]

	==Some Recent Findings==		==Some Recent Findings==
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	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"
	\|		\|
	* '''Review - Genetic Analysis of Human Preimplantation Embryos'''~~<ref name=~~PMID27475859~~><pubmed>27475859</pubmed></ref>~~ "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."		* '''Review - Genetic Analysis of Human Preimplantation Embryos'''{{#pmid:27475859\|PMID27475859}} "Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS."
	* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''~~<ref name=~~PMID24628895~~><pubmed>24628895</pubmed></ref>~~ "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."
	* '''Origins and rates of aneuploidy in human blastomeres'''~~<ref><pubmed>~~22195772~~</pubmed></ref>~~ "The rate of maternal meiotic trisomy rose significantly with age, whereas other types of trisomy showed no correlation with age. Trisomies were mostly maternal in origin, whereas paternal and maternal monosomies were roughly equal in frequency. No examples of paternal meiotic trisomy were observed. Segmental error rates were found to be independent of maternal age."		* '''Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review'''{{#pmid:24628895\|PMID24628895}} "Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat"."
	* '''Preimplantation genetic diagnosis for inherited breast cancer: first clinical application and live birth in Spain'''~~<ref><pubmed>~~22179695~~</pubmed></ref>~~ "Carriers of a mutation in BRCA1/2 genes confront a high lifetime risk of breast and ovarian cancer and fifty percent probability of passing the mutation to their offspring. ...A 28-year-old BRCA1 mutation carrier (5273G>A in exon 19) with a strong maternal history of breast cancer and 2 years of infertility decided to pursue PGD to have a healthy descendent after an accurate assessment of her reproductive options. The procedure was approved by the national regulation authority and a PGD cycle was initiated. Four out of 6 embryos harbored the mutation. The two unaffected embryos were implanted in the uterus. A singleton pregnancy was achieved and a male baby was delivered at term. Consented umbilical cord blood testing confirmed the accuracy of the technique. Individualized PGD for inherited breast predisposition is feasible in the context of a multidisciplinary team."
	* '''Preimplantation genetic diagnosis (PGD) for Huntington's disease: the experience of three European centres'''~~<ref><pubmed>~~22071896~~</pubmed></ref>~~ "This study provides an overview of 13 years of experience of preimplantation genetic diagnosis (PGD) for Huntington's disease (HD) at three European PGD centres in Brussels, Maastricht and Strasbourg. ... PGD workup was based on two approaches: (1) direct testing of the CAG-triplet repeat and (2) linkage analysis using intragenic or flanking microsatellite markers of the HTT gene. In total, 257 couples had started workup and 174 couples (70% direct testing, 30% exclusion testing) completed at least one PGD cycle. In total, 389 cycles continued to oocyte retrieval (OR). The delivery rates per OR were 19.8%, and per embryo transfer 24.8%, resulting in 77 deliveries and the birth of 90 children. We conclude that PGD is a valuable and safe reproductive option for HD carriers and couples at risk of transmitting HD."		* '''Origins and rates of aneuploidy in human blastomeres'''{{#pmid:22195772\|PMID22195772}} "The rate of maternal meiotic trisomy rose significantly with age, whereas other types of trisomy showed no correlation with age. Trisomies were mostly maternal in origin, whereas paternal and maternal monosomies were roughly equal in frequency. No examples of paternal meiotic trisomy were observed. Segmental error rates were found to be independent of maternal age."

			* '''Preimplantation genetic diagnosis for inherited breast cancer: first clinical application and live birth in Spain'''{{#pmid:22179695\|PMID22179695}} "Carriers of a mutation in BRCA1/2 genes confront a high lifetime risk of breast and ovarian cancer and fifty percent probability of passing the mutation to their offspring. ...A 28-year-old BRCA1 mutation carrier (5273G>A in exon 19) with a strong maternal history of breast cancer and 2 years of infertility decided to pursue PGD to have a healthy descendent after an accurate assessment of her reproductive options. The procedure was approved by the national regulation authority and a PGD cycle was initiated. Four out of 6 embryos harbored the mutation. The two unaffected embryos were implanted in the uterus. A singleton pregnancy was achieved and a male baby was delivered at term. Consented umbilical cord blood testing confirmed the accuracy of the technique. Individualized PGD for inherited breast predisposition is feasible in the context of a multidisciplinary team."

			* '''Preimplantation genetic diagnosis (PGD) for Huntington's disease: the experience of three European centres'''{{#pmid:22071896\|PMID22071896}} "This study provides an overview of 13 years of experience of preimplantation genetic diagnosis (PGD) for Huntington's disease (HD) at three European PGD centres in Brussels, Maastricht and Strasbourg. ... PGD workup was based on two approaches: (1) direct testing of the CAG-triplet repeat and (2) linkage analysis using intragenic or flanking microsatellite markers of the HTT gene. In total, 257 couples had started workup and 174 couples (70% direct testing, 30% exclusion testing) completed at least one PGD cycle. In total, 389 cycles continued to oocyte retrieval (OR). The delivery rates per OR were 19.8%, and per embryo transfer 24.8%, resulting in 77 deliveries and the birth of 90 children. We conclude that PGD is a valuable and safe reproductive option for HD carriers and couples at risk of transmitting HD."
	\|}		\|}

Z8600021 at 02:41, 31 August 2016

2016-08-31T02:41:56Z

← Older revision		Revision as of 13:41, 31 August 2016
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	{{Prenatal diagnosis}} \| [[Assisted Reproductive Technology]] \| [[In Vitro Fertilization]]		{{Prenatal diagnosis}} \| [[Assisted Reproductive Technology]] \| [[In Vitro Fertilization]]

	==Some Recent Findings==		==Some Recent Findings==

	{\|		{\|
	\|-bgcolor="F5FAFF"		\|-bgcolor="F5FAFF"