Polyposis Syndromes

Question 1

FAP

Answer 1

Auto dom mutation in APC tumor suppressor gene (chromo 5)

Thousands of polyps after puberty so prophylactic colectomy

Loss of APC –> colon at risk

Then … KRAS mutation –> unregulated cell signaling and adenoma

Then … loss of p53 and DCC –> carcinoma

Question 2

Gardner Syndrome

Answer 2

FAP

Osseous and soft tissue tumors

Congenital hypertrophy of retinal pigment epithelium

Impacted/supernumerary teeth

Question 3

Turcot Syndrome

Answer 3

FAP or Lynch Syndrome

Malignant CNS tumor (like a “turban”) - medullablastoma or glioma

Question 4

Peutz- Jeghers Syndrome

Answer 4

Auto dom

Numerous hamartomas thru GI tract

Hyper-pigmented mouth, lip, hands, genitals

Inc risk breast and GI cancers (colorectal, stomach, SI, pancreatic)

Question 5

Juvenile Polyposis Syndrome

Answer 5

Auto dom

Usually kids < 5 yo

Numerous hamartomas polyps in colon, stomach, SI

Associated w/ inc risk colorectal cancer

Question 6

Lynch Syndrome

Answer 6

HNPCC

Auto dom mutation in mismatch repair genes –> microsatellite instability

Also endometrial, ovarin and skin cancers