Colorectal 2 (659-672)

Question 1

What is familial adenomatous polyposis (FAP)?;

Answer 1

FAP is an autosomal dominant inherited condition in which numerous adenomatous polyps form.

Question 2

How would you clinically diagnose FAP?;

Answer 2

> 100 poylps on colonscopy

Question 3

What gene is assciated with FAP?:

Answer 3

APC

Question 4

What other conditions are associated with FAP?;

Answer 4

Colorectal carcinoma, hepatoblastoma, extracolonic polyps, desmoid tumours, dental anomalies. Gardner syndrome (variant of FAP)

Question 5

Name some features of Gardner syndrome;

Answer 5

FAP, multiple osteomas (skull, mandible and long bones), desmoid tumours, epidermal cysts.

Question 6

What is the screening programmefor individuals with a family history of FAP?;

Answer 6

Genetic screening aged 12. Age 13-> offered flexi sig. If flexi sig NAD the annual colonscopies from age of 18. If flexi sig aged 13 is abnormal then needs annual colonscopies from age 13.

Question 7

What are the key principles of manageing patients with FAPs?;

Answer 7

Will depend on patient choice. Discussion at 18 years old. Definitive management is panproctocolectomy. However patient may want to delay this until after university or having children (as panproctocolectomy is risk for fertility)

Question 8

Name syndromes assocaited with colonic polyps;

Answer 8

FAP, Lynch syndrome. Cowden disease. Peutz-Jeghers.

Question 9

What are the features of HNPCC and how is it diagnosed?;

Answer 9

(aka lynch syndrome) An autosomal dominant genetic condition that is associated with a high risk or colon cancer and endometrial cancer due to inherited genetic mutations that impair DNA mismatch repair. High risk indiviuals identified using the Amsterdam criteria- 3-2-1 rule. 3 or more family members with a confirmed diagnosis of colorectal cancer (at least one first degree realtive), 2 or more successive affected generations. 1 or more colon cancers diagnosed under age 50 years. Plus FAP excluded.

Question 10

What genes are associated with HNPCC?;

Answer 10

DNA mismatch repair genes- MSH2, MLH1, PMS2 and GTBP

Question 11

What other conditions are assocaited with HNPCC?:

Answer 11

Endometrial cancer (most common after colon cancer). Others include- ovarian cancer, stomach cancer, small intestine cancer, hepatobillary tract cancer, brain cancer

Question 12

Name some features of Peutz-Jeghers syndrome?;

Answer 12

Multiple hamatomas in GI tract and increased risk of GI malignancy. Polyps benign but may intussecept. Mucocutaneous hyperpigmentation. Autosomal dominant.

Question 13

What gene is associated with Peutz-Jeghers syndrome?;

Answer 13

STK11 mutation on chromosome 19

Question 14

What is the screening programme for individuals with a family history of Peutz-Jeghers;

Answer 14

Screening starts aged 8-> capsule endoscopy + baseline OGD + baseline colonoscopy. Only needs capsule endoscopy follow up afterwards unless other ix indicated.