These syndromes include juvenile polyposis, Peutz-Jeghers syndrome, hereditary mixed polyposis syndrome, and the phosphatase and tensin homolog gene (PTEN) hamartoma tumor syndromes (Cowden and Bannayan-Riley-Ruvalcaba syndromes), which are autosomal-dominantly inherited, and Cronkhite-Canada syndrome, which is acquired.
The entire coding region of PTEN was screened by single strand conformational polymorphism or direct sequencing for somatic mutations in 16 gingival papillomas, 4 juvenile polyps, 10 esophageal papillomas, and 20 colorectal cancers and for germline mutations in three patients with Cowden disease (including one with Lhermitte-Duclos disease) and one patient each with juvenile polyposis syndrome, Turcot's syndrome, and Cronkhite-Canada syndrome.