Peutz-Jeghers syndrome is an autosomal dominant disorder that is associated with the following characteristics: Melanocytic macules (dark blue or brown moles) These moles can be located around and/or in the mouth including the lips, and around the eyes, nostrils, and anus. Dark moles may also appear on the fingers. The lesions may fade by adulthood. Multiple polyps in the gastrointestinal tract Increased risk of benign (noncancerous) tumors of the ovaries and testes Increased risk of cancers of the stomach, esophagus, breast, colon, and pancreas Peutz-Jeghers syndrome is caused by mutations in a gene on chromosome 19 known as STK11, which functions as a tumor suppressor gene. Learn more about Peutz-Jeghers syndrome.