Phenotypic presentation of MEN1 c.758delC (p.Ser253Cysfs *28) pathogenic variant: a case report.

MEN1 is a rare syndrome caused by mutations in the MEN1 gene. We describe a clinical case of MEN1 syndrome associated with a recently discovered pathogenic mutation of MEN1 gene. A 32-year-old man with a history of osteopenia, nephrolithiasis, hypercalcemia and hypophosphatemia, impaired fasting glucose, and asthenia was admitted to our outpatient unit. Primary hyperparathyroidism, sustained by three hyperplastic parathyroid glands, was diagnosed. Prolactin- and GH-secreting adenomas were ruled out. After undergoing subtotal parathyroidectomy, the patient was diagnosed with non-functioning pituitary adenoma, three pancreatic lesions, and Cushing syndrome sustained by left adrenal adenoma. The patient underwent left adrenal surgery; somatostatin analogue lanreotide was started for the pancreatic lesions; the pituitary adenoma, being small and non-secreting, was not treated. A genetic test was performed to confirm the diagnosis of MEN1 syndrome, finding an association with a recently discovered mutation: the (NM_130799.2):c.758delC (p.Ser253Cysfs^*28) in exon 4.