Prenatal Screening and Testing Flashcards
Explain the components of CFTS (what does this stand for?)
- Compulsory first trimester screening
- Incorporates maternal age, ultrasound nuchal translucency, and serum markers (PAPP-A and free hCG)
- Used to compute Trisomy 21 risk
Explain NIPT (what does this stand for?)
- Non-invasive prenatal testing
- Measures fragments of DNA in the blood
- A certain fraction of this (the fetal fraction) are derived from the fetus
- By reading this DNA, we can determine Trisomy 21 risk
What is the most sensitive T1 test for Trisomy 21
NIPT
What are the components of a quad screening? When does this screening occur?
- HAUI (Howie -> engineer on a quad bike)
- hCG, Alpha-fetoprotein, Unconjugated Estriol, Inhibin-A
What specific genetic conditions can be screened for (no-chromosomal) in pregnancy
- Thalassemia
- Cystic Fibrosis
- Spinal Muscular Atrophy
- Fragile X syndrome
Describe chorionic villus sampling (CVS). When does it occur? What is a potential pitfall?
- Occurs 10-14 weeks
- Sampling of Chorionic Villi for screening
- DNA can be screened via karyotype, chromosomal microarray, and FISH
- Potential pitfall: false pos from placental mosaicism
Describe next generation sequencing. And remind me which diagnostic tests is accompanies
- Accompanies amniocentesis and chorionic villus sampling
- Massive, parallel DNA sequencing
- Can be “panel” of specific genes, whole exome sequencing (what is this?), or whole genome sequencing
Facial features of FASD (what is this?)
- Foetal alcohol spectrum disorder
- Features include underdeveloped jaw, small nose, small top lip, small eye openings, flat philtrum
FASD Diagnostic Criteria
- Confirmed/unknown alcohol exposure
- Developmental impairment in >= 3 domains of cognitive impairment (e.g. academic achievement, memory, executive function)
- Short palpebral fissure, smooth philtrum (love potion), thin top lip
How does alcohol affect a developing foetus at different points in development?
- Weeks 3-14: affects development of heart/nervous system
- 2nd and 3rd trimester: reduced size of cerebellum and basal ganglia, interrupts neurotransmitter regulation
What are the effects of alcohol in infants, toddlers, and later?
Infants: prematurity, facial features, heart defects
Toddlers: developmental delay, difficulties with eye contact (angry alcoholic father)
Later: behavioural defects and mental health issues
How might FASD have compound interest?
Increased risk of:
- Substance use disorder
- Legal trouble
- Incarceration
Broadly, what are some effects that recreational drugs can have on fetuses?
- Low birth weight
- Premature birth
- Birth defects
- Behavioural problems
What are some medications that can cause birth defects?
- ARBs (e.g. candesartan)
- Isotretinoin
- High doses of vitamin A
- Doxy
