prenatal diagnosis and genetic counselling Flashcards
(27 cards)
What is amniocentesis, and when is it performed?
Amniocentesis is a procedure in which a needle is inserted into the amniotic sac to obtain a sample of amniotic fluid, typically performed between 15-20 weeks of pregnancy. It is used to test for chromosomal abnormalities, such as Down syndrome.
What are the risks of amniocentesis?
The risks of amniocentesis include miscarriage (1/200 chance), infection, and the need for repeat testing due to inaccuracy.
What is chorionic villus sampling (CVS), and when is it performed?
CVS involves the removal of chorionic villi from the placenta to test the embryo’s DNA, typically performed between 11-14 weeks of pregnancy. It allows for earlier testing than amniocentesis.
What are the risks of CVS?
The risks of CVS include miscarriage, though it is generally performed earlier in pregnancy than amniocentesis.
What is the purpose of the alpha-fetoprotein (AFP) test?
The AFP test is a blood test that measures the level of alpha-fetoprotein in the mother’s blood. It screens for neural tube defects (e.g., spina bifida, anencephaly) and Down syndrome.
When is the AFP test typically performed?
he AFP test is typically performed between 15-20 weeks of pregnancy.
What conditions can be detected using prenatal diagnosis methods?
Prenatal diagnostic methods can detect conditions such as:
Neural tube defects: e.g., spina bifida, anencephaly.
Trisomy 21 (Down syndrome).
Chromosomal abnormalities (e.g., Turner syndrome, Klinefelter syndrome).
What is the role of genetic counselling?
Genetic counselling helps individuals understand and adapt to the medical, psychological, and familial implications of genetic diseases. It involves providing information, support, and guidance regarding genetic conditions, inheritance patterns, and testing options.
What does genetic counselling typically involve?
Genetic counselling includes:
Collecting family and medical histories to assess genetic risks.
Education about genetic conditions, inheritance patterns, and available testing options.
Support in making informed decisions regarding reproductive choices and management.
What is gene therapy, and what is its current status?
Gene therapy is a technique that involves modifying genes to treat or cure genetic disorders. It may include replacing, inactivating, or repairing a faulty gene. As of now, gene therapy has been tested in clinical trials but is not yet widely approved for human use.
What is the significance of prenatal diagnosis for genetic conditions like Down syndrome?
Prenatal diagnosis allows for early detection of genetic conditions such as Down syndrome, which may lead to early intervention and planning for special care, including addressing possible ocular manifestations like Brushfield spots, refractive errors, and strabismus.
What is the purpose of neural tube defect screening (e.g., spina bifida and anencephaly) in prenatal diagnosis?
Neural tube defect screening aims to detect conditions like spina bifida and anencephaly early in pregnancy, allowing for proper management, preparation, and counseling for the family regarding potential outcomes and interventions.
What are common ocular manifestations in Down syndrome?
Common ocular manifestations in Down syndrome include:
Brushfield spots: White spots on the iris.
Refractive errors: Such as hyperopia and astigmatism.
Strabismus, nystagmus, cataracts, and glaucoma.
What are the ethical considerations in prenatal genetic testing?
The decision-making process regarding whether to undergo testing.
The potential for discrimination based on genetic findings.
Confidentiality and the emotional impact of the results on the family.
What is the significance of genetic testing in prenatal diagnosis?
Genetic testing enables the early detection of genetic disorders and provides families with information to make informed decisions about pregnancy and potential interventions or treatments. It can also guide family planning for future pregnancies.
How can prenatal diagnosis benefit families with a history of genetic conditions?
Families with a history of genetic conditions can benefit from prenatal diagnosis by identifying potential genetic disorders early in the pregnancy, allowing for appropriate interventions, counseling, and planning for the care of the child after birth.
What is the role of screening in prenatal diagnosis?
Screening involves testing for potential genetic conditions without the risk of harm to the fetus, often using blood tests (e.g., AFP), ultrasound, or non-invasive prenatal testing (NIPT). If screening results are abnormal, diagnostic testing like amniocentesis or CVS may be recommended.
What is non-invasive prenatal testing (NIPT), and how does it work?
NIPT is a blood test that analyzes the fetal DNA circulating in the mother’s blood to screen for chromosomal abnormalities such as Down syndrome. It is non-invasive, offering a lower risk than amniocentesis or CVS.
What is the genetic inheritance pattern of Down syndrome (Trisomy 21)?
Down syndrome is typically caused by a trisomy 21 (three copies of chromosome 21) due to a random event during cell division. It is not usually inherited but can occur due to a translocation in some cases, which can be passed on to offspring.
What are the psychosocial aspects of genetic counselling?
Genetic counselling addresses the emotional, psychological, and social aspects of genetic disease, helping individuals and families cope with the implications of genetic testing results, potential diagnoses, and decisions regarding pregnancy.
What are the benefits and limitations of prenatal genetic counselling?
Benefits: Provides information, support, and helps families make informed decisions regarding genetic conditions and pregnancy.
Limitations: May lead to difficult emotional decisions, issues with insurance, and ethics concerns about the decision to continue or terminate a pregnancy based on genetic results.
How do prenatal screening tests differ from diagnostic tests?
Prenatal screening tests (e.g., AFP, ultrasound, NIPT) assess the risk of genetic conditions but cannot definitively diagnose them. Diagnostic tests (e.g., amniocentesis, CVS) provide definitive information and are usually done after a screening test shows a potential risk.
what does the condition of ‘Spina
Fida’ cause??
It causes increased fluid and pressure within the brain
ocular complications of Down’s
syndrome?
High refractive error
* Brushfield spots
* Strabismus
* Bacterial conjunctivitis
