Antenatal genetics Flashcards
When can a) CVS and b) amnio be obtained?
a) 11 weeks
b) 15 weeks +
What is a potential problem with CVS?
Risk of confined placental mosaicism
Methods of chromosome analysis
Karyotyping
aCGH
FISH
QF-PCR
How does QF-PCR analyse chromosome complement for a given chromosome?
Analysis of polymorphic repeat sequences found on that chromosome
When is QF-PCR uninformative?
When only one peak is seen because the person is homozygous for that repeat
Prenatal testing in scotland:
a) 12 weeks
b) 16 weeks
c) 20 weeks
a) booking ultrasound
b) serum screening
c) detailed foetal anomaly scan
Examples where free foetal DNA analysis is currently available
Foetal sex determination for X-linked conditions
Trisomy
Two acrocentric chromosomes joined together
Robertsonian translocation
The odds of what are increased by one parent having a robertsonian translocation?
Offspring having trisomy of either chromosome involved in the translocation
What is the main adverse effect of carrying a balanced translocation?
May cause malsegregation to offspring, which could cause miscarriage of fetal anomaly
