• Guido Fitze, Jakob Cramer, Andreas Ziegler, Mandy Schierz, Matthias Schreiber, Eberhard Kuhlisch, Dietmar Roesner, and Hans K Schackert.
• Department of Paediatric Surgery, University of Technology Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany. Guido.Fitze@mailbox.tu-dresden.de
• Lancet. 2002 Apr 6; 359 (9313): 1200-5.

BackgroundSeveral genes, including the major susceptibility gene RET, have roles in development of Hirschsprung's disease. Results of genetic-linkage analysis of patients with familial disease with both long-segment and short-segment phenotypes have shown close linkage with the RET locus. We aimed to investigate whether both RET mutations and polymorphisms contribute to phenotype of Hirschsprung's disease.MethodsWe looked at the coding region of all 21 exons of the RET proto-oncogene, including the flanking intronic sequences, by direct DNA sequencing in 76 caucasians from Germany with Hirschsprung's disease.Findings20 different mutations were detected in 18 patients. Mutations were under-represented in patients with a homozygous RET c135A/A genotype in association with short-segment phenotype. Short-segment phenotype also arose if the RET mutation was on the c135A allele; conversely, a RET germline mutation on the c135G allele resulted in long-segment phenotype, particularly in heterozygous c135G/A patients.InterpretationThese observations lend support to the idea that both RET alleles have a role in pathogenesis of Hirschsprung's disease, in a dose-dependent fashion. We also showed that the c135G/A polymorphism modifies the phenotype by a within-gene interaction between the c135A variant and a mutation.

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