MUTYH Associated Polyposis
Definition
- Autosomal recessive syndrome characterized by germ line mutation of MUTYH (mutY homolog) resulting in intestinal adenomatous polyposis and a very high incidence of colorectal adenocarcinoma
Alternate/Historical Names
- mutY homolog (gene encoding an enzyme active in DNA repair)
- MYH associated polyposis (MAP)
Covered Separately:
Diagnostic Criteria
- Biallelic germline mutations in MUTYH gene required
- Autosomal recessive
- Gene encodes an enzyme active in DNA repair
- Clinical presentation similar to attenuated familial adenomatous polyposis
- Usually 20-100
- Usually appear in late childhood or later
- Nearly universal development of colorectal adenocarcinoma
- Evenly distributed left vs. right colon
- Histologically indistinguishable from sporadic carcinomas
- Usually low grade
- 50% of patients present with carcinoma
- Some suggestion that carriers of the trait may have a moderately increased incidence of carcinoma
- Extra-colorectal abnormalities infrequent
- Duodenal adenomas 18% incidence
- Carcinoma very rare
- Ovary, bladder, skin and breast cancers reported to be significantly increased (Vogt 2009)
- Gastric and thyroid cancers have been reported
- Not clear if there is an association
- 18-30% of attenuated FAP patients that lack germ line APC mutations have MUTYH associated polyposis
- Rare among classic FAP patients
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 1/31/10, 11/13/11
