What is MYH-associated polyposis (MAP)?
Mutations in the MYH gene increase the chance for an individual to develop multiple colorectal polyps or colorectal cancer. Unlike most polyposis and colorectal cancer disorders, MAP is considered to be an autosomal recessive disorder. This means that individuals with MAP have mutations in both copies of their MYH gene. The number of polyps in individuals with MAP can range from a few to hundreds. The symptoms of MAP overlap with both familial adenomatous polyposis (FAP) and attenuated FAP. Genetic testing for mutations in the MYH gene is available and should be considered in individuals suspected of having FAP or attenuated FAP who do not have mutation in the APC gene. It is not currently known if individuals with only one MYH mutation have a higher than average risk for colorectal polyps and cancer.
