Talk:2015 Group Project 6: Difference between revisions
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associated copyright [https://www.genome.gov/copyright.cfm] | associated copyright [https://www.genome.gov/copyright.cfm] | ||
fish data - [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1120169/] [http://www.nature.com/scitable/topicpage/fluorescence-in-situ-hybridization-fish-327] [http://www.rarechromo.org/information/Other/FISH%20FTNW.pdf] | fish data - [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1120169/] [http://www.nature.com/scitable/topicpage/fluorescence-in-situ-hybridization-fish-327] [http://www.rarechromo.org/information/Other/FISH%20FTNW.pdf] | ||
--[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 11:26, 25 September 2015 (AEST) OK this is such an easy project to find resources for, so where are they? Everyone in research, support groups, genetic inheritance are talking about this topic and the techniques. But this is not on your project page. Like my comments for the other project pages, animal models and media, graphics, statistics, graphs to support the project information???? Your project is not ready for peer review. | |||
--[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:26, 1 September 2015 (AEST) I would like to see some content (sub-headings) on your project page. | --[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:26, 1 September 2015 (AEST) I would like to see some content (sub-headings) on your project page. |
Revision as of 11:26, 25 September 2015
2015 Projects: Three Person Embryos | Ovarian Hyper-stimulation Syndrome | Polycystic Ovarian Syndrome | Male Infertility | Oncofertility | Preimplantation Genetic Diagnosis | Students
Links to Project Discussion Pages: Discussion 1 | Discussion 2 | Discussion 3 | Discussion 4 | Discussion 5 | Discussion 6
This is the discussion page for your project.
- Use this page to discuss online the project with your group members.
- Paste useful resources here.
- Remember to use your signature button to identify who you are when adding content here.
- The following collapsed tables provide starting points for students during project work, you also have tutorials built into practical classes and practice exercises for individual assessmet items.
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Abnormal Development - Genetic FISH Image [1] associated copyright [2] fish data - [3] [4] [5]
--Mark Hill (talk) 11:26, 25 September 2015 (AEST) OK this is such an easy project to find resources for, so where are they? Everyone in research, support groups, genetic inheritance are talking about this topic and the techniques. But this is not on your project page. Like my comments for the other project pages, animal models and media, graphics, statistics, graphs to support the project information???? Your project is not ready for peer review.
--Mark Hill (talk) 16:26, 1 September 2015 (AEST) I would like to see some content (sub-headings) on your project page.
Discussion
Z5088434(talk Would the part you added in indication rather be part of the introduction since it pretty much sums up what the page is about? Maybe go into when PGD and PGS are applied? as for the multiple instances citations: first in text citation has to be like this: [1] and the following ones are like this: [1] (just check for the code in the edit mode, can't figure out how to just show the code without it actually configuring it...)
To Do List
Week 4
- text book summary and some notes
- journal article
- 1 relevant media article
- post in this discussion and on your own page under lab 3 assignment
- for links or informal questions please use the facebook Group
Prenatal Genetic Diagnosis
Headings
- Polar body
- Genetic techniques
- Laws in different countries and states
- Cell extraction from zygotes, blastomeres, morula
- How analysis is conducted e.g. PCR
- Gene Mapping
- Inheritance patterns
- Conducted prior to implantation
In order (?):
- Introduction (GP)
- History/Development (include transition from post to preimplantation) (GP)
- Indications, Inheritance patterns (SL)
- Preimplantation Genetic Diagnosis (PGD)
- Preimplantation Genetic Screening (PGS)
- Cell Extraction Methods, side effect (SK)
- Polar Body Analysis
- Blastomere biopsy
- Trophectoderm biopsy
- Genetic Techniques (GP)
- Fluorescent In Situ Hybridisation (FISH)
- PCR
- Diagnosis (table, gene mapping) (SL)
- Utilization of Diseased Cell Lines (SK)
- Laws/ Legal status (SL)
- Future/Current Research
- Ethics
Content
Legistation for ARTS
Assisted Reproductive Technology Ethics
G12 Country Regulations of Assisted Reproductive Technologies
Cell Extraction Methods
Polar bodies: Applying PGD to polar bodies is desired as it can be used before conception. Since genetic testing can be conducted within twenty four hours this makes it possible for the transfer to the mother at the blastomere stage. However this method isn’t commonly used due to the fact that all oocytes must be tested including those that may not progress to mature and only genetic material from the female can be retrieved [2]
Cleavage stage: This involves the biopsy of the blastomere (6 to 10 cells) [3]. It is advantageous to work on blastomeres as they are totipotent, meaning they can give rise to a diverse range of cells. Studies have also shown that there is no increase in congenital abnormality rates caused by the removal of blastomere cells [2]. Contrarily, studies have shown that the standard removal of two blastomeres at one time will decrease its potential to develop into a blastocyst [4]. Along with the fragility of the cells at this stage, highly skilled embryologists are required to minimise poorly performed biopsies which could subsequently lead to impaired growth and a decrease in implantation. Unlike polar bodies both maternal and paternal genes can be tested if PGD is performed at this stage. [2]
Blastocyst: Performing PGD at this stage is the least common since many patients do not produce embryos healthy enough to reach this stage. Multiple cells can be extracted at this stage for biopsy producing more accurate results. This is possible due to the fact that biopsies have little effect on the development of the embryo. Genetic tests must also be conducted rapidly since implantation is optimal at this stage [2]
Textbooks
The Developing Human 9th Edition: Birth Defects caused by Genetic factors
- Estimated to cause one third of all defects
- Abnormalities in chromosomes are usually due to structural or numerical changes. These can occur in sex chromosomes or autosomes.
- Numerical abnormalities are a result of nondisjunction. Nondisjunction is when a pair or chromatids fail to disjoin during meiosis or mitosis. E.g. Turners Syndrome, Trisomy 21 (Down syndrome) and Trisomy 18 (Edward’s Syndrome).
- Structural abnormalities are usually a result of chromosome breakage followed by reconstitution in an abnormal combination. There are different types of structural abnormalities including translocation and deletion of chromosomes
- Mutations cause 8% of birth defects. It involves the loss or change in the function of a gene which is permanent and heritable.
Williams Obstetrics, Twenty-Fourth Edition: Preimplantation Genetic Testing
- two categories of preimplantation genetic testing: PGS (-Screening) & PGD (-Diagnosis); different indications
- PGS: IVF procedure due to infertility without known genetic abnormalities in patients
- PGD: IVF procedure & genetic testing chosen because of known genetic abnormalities in patients
- Methods:
- Polar body analysis: first and second polar body are extruded following completion of meiosis I and meiosis II
- Advantages: does not harm embryo, can be used to detect 146 Mendelian disorders, reported 99% accuracy
- Disadvantages: paternal genetic contribution is not investigated --> additional procedures
- Blastomere biopsy: embryo is 3 day old, 6-8 cells stage, most commonly used, hole is made in zona pellucida to retrieve one cell
- Disadvantages: 10% pregnancy reduction,"mosaicism of the blastomeres may not reflect the chromosomal complement of the developing embryo"
- Trophectoderm biopsy: 5-6 day old blastocyst, 5-7 cells are removed
- Advantage: no cells removed from embryo
- Disadvantage: additional procedures may be necessary because of later stage of developing embryo (cryopreservation, implantation at later IVF-cycle)
- Polar body analysis: first and second polar body are extruded following completion of meiosis I and meiosis II
Maternal, Fetal & Neonatal physiology: a Clinical perspective :Prenatal Diagnosis and Maternal, Fetal & Neonatal physiology: a Clinical perspective: Prenatal Diagnosis:
Prenatal diagnosis is the screening process that tests an early fetus for overall growth, complications of pregnancy, birth defects and chromosomal or genetic abnormalities within the first 2 trimesters. It aims to provide the parents with as information as possible to help them make an informed decision about the infants quality of life. In 90-95% of the cases negative outcomes occur; confirming the healthy state of the fetus, should a genetic abnormality be present, it provides the parents with the opportunity to investigate further with other tests, and possible fetal therapeutic treatments available as well plan and prepare for the disabled infant or to terminate the pregnancy.
- Indicators for prenatal screening/ high risk factors include:
- maternal ages > 35 years
- paternal ages > 50-55
- history of 2+ miscarriages
- previous pregnancy or family history of a preexisting genetic or chromosomal disorder
- suspected carriers of genetic disorders
- maternal disease/condition present (high BP, diabetes)
- abnormal ultrasound or serum test results within the first 2 trimesters
- family history of neural tube or other birth defects
- Ultrasonography:
- high frequency sound waves are used to generate a image of the fetus
- relatively non-invasion; its conducted transabdominally or transvaginally ( producing a higher resolution image)
- It reveals the presence/absence of congenital abnormalities, characteristics of fetal growth and development, uterine development status; amount of **amniotic fluid, placental position, umbilical blood flow and the presence of multiple gestation.
- (if abnormalities are detected further testing is recommended)
- Amniotic Fluid Analysis/:
- samples are obtained through amniocentesis
- the amniotic fluid is analyzed for its biochemical composition
- earlier in the pregnancy it can be examined for sex determination and to diagnose genetic or chromosomal disorders present.
- Later into the pregnancy it provides an indication of fetal maturity and well being
- Feta; cells recovered from the amniotic fluid can be cultured for specific karyotypes, to test for Chromosomal Abnormalities, and analysed for Alpha- fetoprotein (AFP) a biochemical marker of metabolic disorders and neural tube defects as well as other abnormalities.
- Amniocentesis- occurs usually between weeks 14-20 as amniotic fluid has reached the optimal volume (150-250mls) allowing 20-30mls to be removed with a relatively low risk or fetal or maternal complication, and in time for a 2nd trimester abortion.
- early amniocentesis ( before week 13) increase the risk of fetal loss, leakage of essential amniotic fluid and talipes equinovarus.
- Chronic Villus Sampling (CVS):
- occurs roughly 10-13 weeks after last menstrual cycle, ensuing a sufficiently developed chorionic villi but before the chorion laeve forms the definitive placenta.
- ultrasounds is used to locate the gestational sac and implantation then a transcervial or transabdominal approach is used to aspirate living tropoblast tissue.
- sample is analyzed for chromosomal abnormalities or with enzyme assay.
- advantages: earlier diagnosis , decreased waiting period
- disadvantages: risk of spontaneous abortion, bacterial infection, bleeding, leakage of amniotic fluid, inability to diagnose neural tube defects this early, early cleavage (before wk 10) is associated with increased risk of limb defects (due to insufficiently developed chronic villi)
- Umbilical Blood Sampling:
- can occur as early as 16 weeks
- using the umbilical cord to obtain fetal blood samples - with real time ultrasound
- used to diagnose inherited blood disorders, to detect congenital infections, to assess fetal anemia and in treatments such as blood transfusions.
- disadvantages: risks of infection, preterm labor, thrombosis, bleeding & transient fetal arrhythmia
- Fluroscent in Situ Hybridisation (FISH)
- rapidly detects (within 24 hours of testing ) the presence of Trisomies 21, 13 and 8 and alterations in sex chromosomes in uncultured cells.
- early diagnosis allows the opportunity for intervention with fetal therapies:
- surgical intervention urinary tract obstruction ; aiming to reduce prenatal renal damage
- fetal transfusions ( feta anemia
- fetal medical treatmetn ( fetal cardiac arrhythmias,impaired thyroid function etc.) treatment occurs usually through the mother
- infusions for hematologic conditions
- stem cell transplantation
- gene therapy
- pharmocolic interventions
textbooks used :
- Maternal, Fetal & Neonatal physiology: a Clinical perspective [7]
- Langman's Medical Embryology (12th ed.)Chapter 9, pages 125-129 [8]
the following are two articles about a newly available and accessible prenatal non- invasive genetic test- Blood sampling:
- Report on Cutting edge prenatal screening technology to become available in Australia [9]
- Blood Test takes risk out of prenatal testing [10]
- Prenatal screening and Diagnostic Tests Information Pamphlet [11]
Articles
<pubmed>24810687</pubmed>
<pubmed>23773313</pubmed>
<pubmed>26201722</pubmed>
<pubmed>26168107</pubmed> This article reviews the cytogenetic techniques and embryo biopsies required for PGD & PGS and gives an account on the differences in PGD for single gene defects and chromosomal translocations.
<pubmed>22723007</pubmed>
This article gives relatively recent and detailed information on the three types of biopsy performed on embryos at different stages of development (before conception, after fertilization, and early cleavage or blastocyst stage)
<pubmed>24515905</pubmed>
This article reviews indications for PGD focusing on single gene disorders.
<pubmed>20966459</pubmed>
This article gives detailed laboratory instructions and guidelines for PGD procedures, which might be useful for the methodological part of the website
The following articles are about diseased cells/embryos derived from PGD procedures for further research:
<pubmed>23242925</pubmed>
<pubmed>22735930</pubmed>
Other articles
<pubmed>21748341</pubmed>
<pubmed>26259216</pubmed>
<pubmed>26258137</pubmed>
<pubmed>22404048</pubmed>
<pubmed>26238130</pubmed>
<pubmed>26168107</pubmed>
IVF and prenatal genetic testing in Australia
[[6]]
the following are two articles about a newly available and accessible prenatal non- invasive genetic test- Blood sampling: [[7]] [[8]]
- ↑ 1.0 1.1 <pubmed>...</pubmed>
- ↑ 2.0 2.1 2.2 2.3 Coward, K. & Wells, D. (2013). Textbook of Clinical Embryology New York: Cambridge University Press.
- ↑ <pubmed>11325751</pubmed>
- ↑ <pubmed>19773223</pubmed>
- ↑ Moore, K.L., Persaud, T.V.N. & Torchia, M.G. (2011). The developing human: clinically oriented embryology (9th ed.). Philadelphia: Saunders.
- ↑ Cunningham F, Leveno K.J., Bloom S.L., Spong C.Y., Dashe J.S., Hoffman B.L., Casey B.M., Sheffield J.S. (2013). Prenatal Diagnosis. In Cunningham F, Leveno K.J., Bloom S.L., Spong C.Y., Dashe J.S., Hoffman B.L., Casey B.M., Sheffield J.S. (Eds), Williams Obstetrics, Twenty-Fourth Edition. Retrieved August 25, 2015 from {http://accessmedicine.mhmedical.com/content.aspx?bookid=1057&Sectionid=59789152.}
- ↑ Blackburn, S.L. (2003) Maternal, Fetal & Neonatal physiology: a Clinical perspective (2nd ed.). Seattle: Saudners
- ↑ Sadler T.W.(2012) Langman's Medical Embryology (12th ed.) Philadelphia: Lipincott, Wiliams & Wilkins, a Wolters Kluwer Business
- ↑ Carbonell, R. Shinners, A. Amor, D. Mark, D. (2015) Report on Cutting edge prenatal screening technology to become available in Australia: Prepared for ABC news, PM with Mark Colvin. Retrieved from {http://www.abc.net.au/pm/content/2015/s4203200.htm}
- ↑ Begley, S. (05/07/2015) Blood Test takes risk out of prenatal testing. ABC Science. Retrieved from {http://www.abc.net.au/science/articles/2012/07/05/3539549.htm}
- ↑ Western Australia. Department of Health Genetics Council Prenatal Diagnosis Committee (2011)Prenatal screening and Diagnostic Tests. Retrieved from {http://www.health.wa.gov.au/docreg/Education/Prevention/Genetics/HP3131_prenatal.pdf}