genetics Flashcards
most malformation occur by ___ wks
8
cells are committed when it is a ____
blastocyst
anything causing malformation
teratogen
__% malformations are caused by unknown causes
75
biggest chem teratogen
alcohol
alcohol affects ____
development of brain
What is Torch?
Toxoplasma, other less common infections, rubella, cytomegalovirus, herpes
congenital rubella syndrome characterized by:
microcephaly, microphthalmia, CHD
deletion chrom abnormality (of 11)
WAGR (tumour on kidney, arevia, genital abnormalities, retardation)
2 types of chrom abnormalities
Structural and Numerical
Trisomy 21 involves ___ translocation
Robertsonian (21–>14 or 22)
extra chromosomes come from meiotic ____
nondisjunction
most common numerical chrom abnormality
trisomy 21 (1/800)
to test for Trisomy 21 in pregnancy, use ___ biopsy
chorionic
in autosomal dominant disorders, offspring has __% chance inherit
50
syndrome characterized by mutation in fibrillin and multisystem disorder
marfan’s syndrome
most common autosomal recessive disorder that affects gene for coding Cl transport channel
cystic fibrosis
progeny of 2 HZ for AR disorder is ___% N, ___% affected, ___% carriers
25; 25; 50
X-linked recessive disorders incidence higher in ____
males
hemophilia is due to mutation in ___ gene
factor VIII