Long-term follow-up of an 8-year-old boy with insulinoma as the first manifestation of a familial form of multiple endocrine neoplasia type 1 Seguimento de longo prazo em um menino de 8 anos de idade com insulinoma como primeira manifestação de neoplasia endócrina múltipla tipo 1

2 SUMMARY Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant hereditary cancer syn- drome characterized mostly by parathyroid, enteropancreatic, and anterior pituitary tumors. We present a case of an 8-year-old boy referred because of hypoglycemic attacks. His diagnosis was pancreatic insulinoma. Paternal grandmother died due to repeated gastroduodenal ulcerations and a paternal aunt presented similar manifestations. At a first evaluation, the father presented only gastric ulceration but subsequently developed hyperparathyroidism and lung carcinoid tumor. During almost 15 years of follow-up, three brothers and the index case presented hyper- parathyroidism and hyperprolactinemia. Molecular study showed a G to A substitution in intron 4, at nine nucleotides upstream of the splicing acceptor site, causing a splicing mutation. All affected members of the family have the same mutation. Paternal grandmother and aunt were not studied and the mother does not carry any mutation. MEN1 is a rare condition that requires permanent medical assistance. Early clinical and genetic identification of affected individuals is essential for their own surveillance and also for genetic counseling.