Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid, pancreatic islet and pituitary gland tumors. It is caused by mutation of the MEN1, a tumor suppressor gene, with more than 400 different MEN1 mutations having been described. Herein is reported the case of a 26-year-old woman who had complained of personality and behavior changes, coupled with repetitive loss of consciousness. Her random plasma glucose and insulin were 68 mg/dL and 67.3 microIU/mL, respectively. Two pancreatic masses were noted on abdominal computed tomography, with hypercalcemia noted from a routine chemistry test. Her diagnosis was that of MEN1; therefore, her first-degree relatives were also screened. DNA analysis was also performed, from which a MEN1 gene mutation (738del4 -> new nomenclature: 628del4) was detected. Knowledge of the MEN1 mutation status could provide early recognition of a tumor.