Gardner's syndrome is a genetic disorder characterized by the presence of multiple polyps in the colon together with tumors outside the colon. The extracolonic tumors may include osteomas of the skull, thyroid cancer, epidermoid cysts, fibromas and sebaceous cysts. The countless polyps in the colon predispose to the development of colon cancer.
Gardner's syndrome is inherited in an autosomal dominant manner. Typically, one parent has Gardner's syndrome. Each of their children, male and female alike, are at 50% risk of inheriting the gene for Gardner's syndrome and manifesting it.
New genetic and molecular information has caused some genetic disorders to be split into multiple entities while other genetic disorders merge into one condition. After existing for most of the second half of the 20th century, Gardner's syndrome has vanished as a separate entity. It has been merged into familial adenomatous polyposis (FAP) and is now considered simply a phenotypic variant of FAP.