Multiple endocrine neoplasia type 1 presented with manic-depressive disorder: a case report with an identified MEN1 gene mutation

We report a case of multiple endocrine neoplasia type 1 who had repeatedhypoglycemic episodes and had previously been diagnosed with bipolarmanic-depressive disorder. The patient had a positive family history ofmultiple endocrine neoplasia type 1 and had multiple pancreatic endocrinetumors, hyperparathyroidism and possibly a pituitary tumor. The pancreatictumors were resected by subtotal pancreatectomy and examined byhistochemical staining and gene analysis. The tumor cells were positive forimmunoreactive insulin and glucagon. A microsatellite polymorphism analysisrevealed loss of heterozygosity on 11q13 in the tumors. By polymerase chainreaction-based nucleotide sequencing, we identified a germline mutation483del2 of the MEN1 gene in the normal pancreatic tissue of the patient.This mutation causes a shift of the reading frame of menin mRNA at codon125. It seems that the wild type allele of the MEN1 gene had been lost inthe tumor cells whereas the mutant allele remained intact. This is thefirst identified MEN1 gene mutation in Japanese families and is differentfrom all MEN1 gene mutations reported previously.