Genetics

Question 1

What are autosomal dominant fetal abnormalities?

Answer 1

Recurrence rate: 50%
Marfan’s
Neurofibromatosis
Huntington’s Chorea
vWD
PCKD with adult onset

Question 2

What are autosomal recessive fetal abnormalities?

Answer 2

Recurrence rate: 25%
PKU
Congenital adrenal hyerplasia
Thalassemia
Cystic fibrosis
Galactosemia
Metabolic disorders (Tay sachs, mucopoisaccaridosis)

Question 3

What are sex-linked fetal abnormalities?

Answer 3

Recurrence rate: 50%
Diabetes Insipidus
Hemophilia
Muscular Dystrophy
Placental sulfatase Deficiency
Testicular Feminization

Question 4

What are multifactorial fetal abnormalities?

Answer 4

Recurrence rate 3-5%
Nural tube defect
Anencephaly
Spina Bifida
Congenital Heart Disease
Mullerian Agenesis
Endometriosis

Question 5

What is Trisomy 18?

Answer 5

Edwards syndrome: 1/3500
- POLYHYDRAMNIOS, FGR
<10% survive to a year
HCG is UP (King Edward clenched his fingers in his rocking chair)
- SGA, 2 vessel cord, rocker bottom feet, short sternum, clenched fingers

Question 6

What ist trisomy 13?

Answer 6

Pat syndrome
1/5000 <3% survive to 3 years
- SGA with 13 triad: facial clefts, ocular anomalies, polydactyly

Question 7

What is 5P Syndrome?

Answer 7

Cri du Chat
1/20,000
High pitched cat cry, epicanthal fold, mental retardation

Question 8

What is Turner Syndrome

Answer 8

1/3500 (like Trisomy 18)
<10% survive to 1 year
Short stature, web neck (cystic hygroma), pigmented nevi, los hairline, trouble hearing (arched palate), normal IQ, wide spaced nipples, shield chest, spread gonads, aortic coarctation, renal anomalies

Question 9

What are conditions with high MSAFP?

Answer 9

OPEN neural tube defects (omphalocele, gastroschisis)
Congenital nephrosis
Cystic Hygroma
Twins
Fetal Death
Osteogenesis imperfecta

Question 10

What are conditions with low MSAFP?

Answer 10

Chromosomal Trisomies (13, 18, 21)
Gestational Trophoblastic Disease
Fetal Death
Overestimated gestational age
Increased maternal weight

Question 11

What is a cystic hygroma?

Answer 11

lymphatic lesion
left posterior triangle of the neck
assoc w/ hydros, Turner’s, Noonan syndrome

Question 12

What is CMV?

Answer 12

most common maternal congenital infection. Vertical transmission most common in 3rd trimester.
-Echogenic bowel (intra-abdominal calcifications) and symmetric IUGR.
30% risk vertical infection
effects: hearing loss, mental retardation, visual impairment, cerebral palsy
if positive titers, do avidity testing: determine primary vs. secondary infection in pregnant woman–strength of attachment of IgG to antigen. high avidity=infection occurred longer ago, lower risk for fetus. Positive test 4-6 weeks after maternal infection.

Question 13

Which are single gene disorders?

Answer 13

CF, sickle cell anemia, hemophilia, Tay-Sachs, hemachromatosis, muscular dystrophy, Huntington’s