Genetics

Question 1

List a few autosomal recessive disorders

Answer 1

Cystic Fibrosis
Thalassemia’s
Sickle Cell
Tay Sachs

Question 2

List a few autosomal dominant disorders

Answer 2

Marfan Syndrome
Osteogenesis imperfecta
BRCA1/2
Lynch Syndrome

Question 3

List a few x-linked conditions

Answer 3

Hemophilia
Fragile X
Muscular Dystrophy

Question 4

List a few multi-factorial conditions

Answer 4

Cleft lip/palate
Congenital heart defects

Question 5

Most common genetic abnormality found in early miscarriages?

Answer 5

Turner Syndrome (not related to maternal age)

45 XO (gonadal dysgenesis)

Question 6

Most common presenting symptoms of Turners syndrome?

Answer 6

Short stature

Other characteristics:
Web neck
Shield chest
Cystic hygromas on US
Renal anomalies
Aortic dilation and dissection

Question 7

Gyn implications of Turner’s Syndrome?

Answer 7

• Normal intellectual function
• Hypoestrogenic state
• No pubertal breast development or menarche
• Usually infertile, rare fertility in cases of mosaic
• Increased risk for osteoporosis
  MUST supplement with HRT and calcium

Question 8

Age specific risks of delivering an infant with Trisomy 21?

Answer 8

Age 35 1:350

Question 9

Age specific risk of delivery an infant with any major genetic anomaly?

Answer 9

Age 35 1:200

Question 10

What causes Trisomy 21?

Answer 10

Non-disjunction (majority, sporadic, age related)
Failure of all chromatids to separate along the metaphase plate during mitosis so that one pole receives an extra chromosome

Translocation (familial inheritance of down syndrome)
A portion of one arm of a chromosome detaches and reattaches on another arm of a different chromosome (can be balanced if no chromosomal material is lost, and unbalanced if material is lost)