Genetics

Question 0

What are BRCA?

Answer 0

Tumour suppressor genes (inhibit cell growth). Mutations in both alleles must occur.
BRCA1: 17q
BRCA2: 13q

Question 1

Incidence of BRCA1/2 breast cancer

Answer 1

5-10% breast cancer
BRCA1: 65% lifetime risk breast and 40% risk ovarian
BRCA2: 45% breast and 11% ovarian

Question 2

Treatment for BRCA

Answer 2

Annual MRI for 30-50yrs

Bilateral prophylactic mastectomy reduces risk by 90%

Question 3

Genetics clinic referral for familial colorectal cancer

Answer 3

Two affected 1st degree relatives <60 (RR x2)
FAP
HNPCC

Question 4

Familial adenomatous polyposis

Answer 4

Mutation in APC at 5q
Penetrance ~100% for colorectal cancer by 50yrs
Treat by total colectomy

Question 5

Peutz-Jeghers syndrome

Answer 5

Mutation in STK11 at 19p14

10-20% lifetime risk of colorectal cancer

Question 6

Hereditary non polyposis colorectal cancer

Answer 6

Familial aggregation: colorectal, uterus, ovary, stomach, renal, pelvis, small guy and/ or pancreas
Mutation of DNA mismatch repair gene
Autosomal dominant w/incomplete penetrance

Question 7

Von Hippel Lindau syndrome

Answer 7

Autosomal dominant

Bilateral renal cysts, retinal/cerebellar haemangioblastoma, phaeochromocytoma