Genetics Flashcards
What are the different types of DNA based on the size of mutations?
3,000,000 pb; chromosomal analysis
aCGH for deletions/ duplications
PCR and sanger sequencing
1bp; next generation sequencing
How are balanced chromosomal rearrangements investigated?
Chromosomal analysis
How are small mutations investigated?
Next generation sequencing
How are chromosomal deletions/ duplications investigated?
aCGH
What will the anomaly scan at 20 weeks of pregnancy look at?
Cardiac (12-20)
Microcephaly (after 22 weeks)
Short limbs (22 weeks)
Brain malformations
How is diagnosis and risk estimation performed in pregnancy?
FHMx Pregnancy history Maternal history Scan findings Clever tests
What occurs after a diagnosis is given in pregnancy?
Recurrence risk
Treatment options
Prognosis
Genetic tests
What are some examples of genetic conditions that affect maternal health in pregnancy?
Myotonic dystrophy
Haemophilia A or B
Hereditary Haemorrhagic Telangiectasia
What DNA testing can be done in pregnancy?
PCR based; 2-3 days
Southern Blotting; 2-3 weeks
Chorionic villus biopsy; 11.5+ weeks
Amniocentesis 16+ weeks
What is the best genetic management?
Non invasive foetal sexing via maternal serum
Chorionic villus biopsy is male
Why is foetal pathology required?
Often only way of establishing diagnosis
Obtains important info for parents
Confirms prenatal findings
What is a preimplantation genetic diagnosis (PGD)?
Performing a genetic test on an embryo before re-implanting one with the “correct” genotype
What are the reproductive options if you are at risk of a pregnancy affected with a genetic disorder?
Have no further children Take a chance Prenatal testing Gamete donation Adoption Preimplantation diagnosis
How is PGD used to determine sex?
FISH
Different coloured probes to label chromosomes X, Y and 18 (control)
What is the downside of PGD?
Required IVF like procedure Expensive Invasive 30% take home baby rate per cycle DNA analysis less reliable than prenatal testing Multiple pregnancy risk
