MYH-associated polyposis (MAP) is associated with multiple precancerous polyps in the colon and rectum, similar in number to the milder form of FAP. Doctors have determined it is caused by a mutation in a gene called MYH that must be inherited from both parents.

Because each parent has only one copy of the mutated gene, the parents themselves often don’t have multiple colon polyps. That means that although this condition is inherited, there may not be a strong family history of multiple colon polyps or colorectal cancer in close family members. Early research suggests that MAP significantly increases your risk for colorectal cancer. It’s still unclear what other risks for cancer MAP may pose.