Exclusion of APC and MCC as the With Familial Juvenile Polyposis Gene Defect in One Family

Bac&fround: In familial juvenile polyposis, multiplejuvenile polyps occur throughout the colon. The genetic defect has not been characterized. The risk of colon cancer is increased, although the magnitude of the lncreased risk is controversial. The hypothesis of this study was that the genetic defect is within a tumor suppressor gene, possibly one already known to be inactivated in coiorectal neoplasia. Methods: Linkage analysis using the short tandem repeat polymorphism 058346 was performed to determine if juvenile polyposis was linked to either APC (adenomatous polyposis coli) or MCC (mutated in colorectal carcinoma) genes within a single large family. Results: A family in which eight subjects have been affected by juvenile polyposls over three generations is described. Six affected subjects had colectomles in childhood, but the two who have so far survived beyond 35 years of age have developed adenocarcinoma of the jejunum. Within this family, linkage analysis excluded linkage of the juvenile polyposis trait to either APC or MCC. Conclusions: In a family with juvenile polyposis with a clear predisposition to malignancy, including carcinoma of the jejunum, APC and MCC were not the defective genes causing the condition.