GERMLINE MUTATION OF THE RET PROTOONCOGENE IN CHILDREN WITH TOTAL INTESTINAL AGANGLIONOSIS

To clarify the pathogenesis of total intestinal aganglionosis, an extr emely severe form of neural crest-derived cell migration disorder of t he gut, the authors studied possible germline mutations of the RET pro to-oncogene (10q11.2) in five pedigrees at high risk for congenital ag anglionosis. All five patients analyzed were boys, and one had a famil y history of Hirschsprung's disease. Genomic DNA was extracted from ly mphoblastoid cell lines established from patients and their relatives. Polymerase chain reaction (PCR) products, which were amplified using specific primers (RET; exon 1 similar to 20), were electrophoresed to analyze the single-strand conformational polymorphism (SSCP) patterns. DNA sequences were determined in pedigrees showing abnormal SSCP band s. Among the five patients, three germline mutations were found in the receptor tyrosine kinase domain (exon 15; codons 884, 897, and 904). Amino acid substitutions of the Ret protein were predicted based on th e mutated nucleotide changes. Phenotypic variations of congenital agan glionosis may depend on the RET mutation pattern and other genetic or environmental determinants. In our series of patients, male sexuality and germline mutation of the RET tyrosine kinase domain were the most likely factors contributing to this form of Hirschsprung's disease. Co pyright (C) 1997 by W.B. Saunders Company.