Isolated intestinal ganglioneuromatosis with a new mutation of RET proto-oncogene.

A 13-year-old boy with a history of juvenile polyps of the colon was subsequently found to have isolated intestinal ganglioneuromatosis without any other features characteristic of multiple endocrine neoplasia (MEN) 2B. Screening for MEN 2B revealed a polymorphism of the RET proto-oncogene at codon 691 with a glycine to serine conversion. This mutation has not been described before in association with ganglioneuromatosis and MEN 2B. The phenotype and presentation are compared with those of previous case reports.