To analyze the autosomal dominant inheritance of five families of adenomatous polyposis (FAP).

Five FAP families were investigated and examined. Peripheral blood and feces were taken for whole-exon sequencing to screen colorectal cancergenes. Colonoscopy was performed and biopsy tissues were taken for pathological analysis.

In the five families, FAP occurred in successive generations. When the father or mother had FAP, the probability of FAP occurred in the offspring was equal (50%) without gender difference. All the patients had adenomatous polyposis coli gene (APC) mutation. Some patients had more than two types of tumors.

In families with a history of FAP, FAP generally does not develop in juveniles, and APC gene testing and colonoscopy are needed in adults. Once adenoma is found, endoscopic treatment should be performed as soon as possible to avoid the occurrence of colorectal cancer.