SMAD genes in juvenile polyposis.

Juvenile polyposis (JP) is a dominantly inherited condition characterized by the development of multiple hamartomatous tumors, juvenile polyps, in the gastrointestinal tract. The aim of this study was to clarify the role of SMAD4 in JP. DNA from four unrelated JP kindreds and three sporadic JP cases was available for mutation screening. Two truncating defects (one in a familial and one in a sporadic case) and one missense change (in a familial case) that was absent in 55 control samples were detected. To study the possibility that germline mutations in other genes encoding different components of the TGF-beta signaling pathway may be present in these JP patients, mutation analyses of the SMAD2, SMAD3, and SMAD7 genes were also performed. No mutations of these genes were detected in any of the patients. Our results confirm that SMAD4 is a gene predisposing to JP and suggest the existence of further JP loci other than the SMAD2, SMAD3, or SMAD7 genes. Genes Chromosomes Cancer 26:54-61, 1999. Copyright 1999 Wiley-Liss, Inc.