Multiple endocrine neoplasia type 1 familial case in a patient with insulinoma and primary hyperparathyroidism: First report in literature and in the Costa Rican population of the c.1224_1225insGTCC pathogenic variant

Abstract

AbstractMultiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder without a good genotype–phenotype correlation, characterized by tumor predisposition in the parathyroid gland, anterior pituitary, and pancreatic islet cells. Here, we describe a 37‐year‐old male with previous history of nephrolithiasis, with a 1‐year history of recurrent hypoglycemic episodes. Physical examination revealed the presence of two lipomas. Family history revealed primary hyperparathyroidism (PHPT), hyperprolactinemia, and multiple non‐functioning pancreatic neuroendocrine tumors. Initial laboratories revealed hypoglycemia and primary hyperparathyroidism. A fasting test was positive after 3 hours of initiation. An abdominal CT Scan demonstrated a 28 × 27 mm mass in the pancreatic tail and bilateral nephrolithiasis. A distal pancreatectomy was done. After surgery, the patient persisted with hypoglycemic episodes that were managed with diazoxide and frequent feedings. A parathyroid Tc‐99 m MIBI scan with SPECT/CT imaging demonstrated two hot uptake lesions compatible with abnormally functioning parathyroid tissue. Surgical treatment was offered; however, the patient decided to postpone the procedure. Direct sequence analysis of MEN1 gene revealed heterozygosity for a pathogenic insertion c.1224_1225insGTCC (p.Cys409Valfs*41). DNA sequence analysis was done to six of his first‐degree relatives. A sister with clinical diagnosis of MEN1 and a pre‐symptomatic brother were positive for the same MEN1 variant. To our knowledge, this is the first report of a genetically confirmed case of MEN1 in our country and is the first report in literature of the c.1224_1225insGTCC variant related to a clinically affected family.