Familial adenomatous polyposis (FAD) or the old name of polyposis coli, is the most important form of hereditary polyposis syndrome of the colorectum. It is autosomally dominantly transmitted and manifests as numerous adenomatous polyps (>100) in the colorectum. Carcinomatous changes develop in these polyps with time. The gene (APC gene) is cloned at chromosome 5.

In this picture, numerous polyps of the tubular type can be seen.