Presence of Multiple Endocrine Neoplasia-1 Mutations in Patients with Primary Hyperparathyroidism Detected on Clinical and Sonographical Suspicion: Report of 2 Novel Mutations

Objective: This study aims to evaluate the presence of multiple endocrine neoplasia-1 mutations in patients with primary hyperparathyroidism detected on clinical and sonographical suspicion. Methods: We scanned the medical records of 361 patients with primary hyperparathyroidism between January 2010 and December 2017. Results: Fourteen of 361 patients (i.e., 2 males and 12 females) with primary hyperparathyroidism were evaluated genetically upon clinical and sonographical suspicion. Menin gene mutations were found in 3 of 14 patients (21.4%) patients. The frequency of multiple endocrine neoplasia-1 (n = 3) was estimated to be 0.83% in all patients with primary hyperparathyroidism (n = 361). Data of 4 patients with menin mutation analyses were as follows: case 1: A 37-year-old man presented with a 14-year history of recurring nephrolithiasis. He was diagnosed with primary hyperparathyroidism. Genetic analysis was reported as multiple endocrine neoplasia-1: c.643_646delACAG (p.Thr215Serfs*13) heterozygote; case 2: A 35-year-old man with primary hyperparathyroidism and prolactinoma was diagnosed. Genetic analysis was reported as multiple endocrine neoplasia-1: c.654+1G>A heterozygote; case 3: A 26-year- old woman with hyperammonemia, partial empty sella, and hyperprolactinemia was evaluated. Genetic testing revealed heterozygote genomic changes in c984c>a in the multiple endocrine neoplasia-1 gene on the seventh exon; case 4: A 27-year-old man was diagnosed with nephrolithiasis when he was 19 years old. He had both primary hyperparathyroidism and prolactinoma. Multiple endocrine neoplasia-1 and CDKN1B genetic mutation analyses were negative. Because mutation-negative syndromes could not be ruled out, a neck exploration was performed, and a parathyroid adenoma was excised. Conclusions: Patients with primary hyperparathyroidism should be evaluated for multiple endocrine neoplasia-1 mutations upon clinical and sonographical suspicion. It should be noted that an individual with the multiple endocrine neoplasia-1 gene mutation has a 100% penetrance up to the age of 40-50 years. Additionally, 2 novel multiple endocrine neoplasia-1 mutations were identified.