Exome Sequencing Reveals Germline SMAD9 Mutation That Reduces Phosphatase and Tensin Homolog Expression and Is Associated With Hamartomatous Polyposis and Gastrointestinal Ganglioneuromas.
الكلمات الدالة
نبذة مختصرة
Hamartomatous polyposis syndromes (HPS) account for a small but appreciable proportion of inherited gastrointestinal cancer predisposition syndromes; patients with HPS have an increased risk for colon and extracolonic malignancies. We present a unique case of familial juvenile polyposis syndrome associated with gastrointestinal ganglioneuromas of unknown etiology. The patient was tested for HPS-associated genes, but no mutation was detected. Exome sequencing identified a germline heterozygous mutation in SMAD9 (SMAD9(V90M)). This mutation was predicted to be an activating mutation. HEK cells transfected to express SMAD9(V90M) had reduced expression of phosphatase and tensin homolog; this reduction was also observed in a polyp from the patient. We have therefore identified a new susceptibility locus for HPS. Patients with hamartomatous polyposis in the colon associated with ganglioneuromatosis should be referred for genetic assessments.