SMAD genes in juvenile polyposis

Juvenile polyposis OF) 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 SM AD4 in JP. DNA from four unrelated JP kindreds and three sporadic JP cases was available for mutation screening. Two truncating defects tone in a fami lial and one in a sporadic case) and one missense change tin a familial cas e) that was absent in 55 control samples were detected, To study the possib ility that germline mutations in other genes encoding different components of the TGF-beta signaling pathway may be present in these JP patients, muta tion 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 o f further JP loci other than the SMAD2, SMAD3, or SMAD 7 genes. (C) 1999 Wi ley-Liss. Inc.