Endocrine Abstracts

Aim: Multiple endocrine neoplasia-1 (MEN-1) is described in patients as presence of clinical two or more primary MEN-1 associated tumors or patients who have MEN-1 clinics and also have family members with MEN-1 associated tumors. It is associated with loss of activation genetic mutation in a tumor suppressor gene called Menin. MEN-1 is associated with tumors involving the parathyroid glands, anterior hypophysis, and pancreatic islet cells. Primary hyperparathyroidism (PHPT) is the most common feature of MEN-1. In this study, we aimed to evaluate the frequency of MEN-1 associated mutation in patients with PHPT.

Materials and methods: We scanned the medical records of 361 patients with PHPT who were followed-up in our department between January 2010-December 2017. We presented the data of 14 patients who had genetic analysis due to suspicious clinical findings.

Results: Totally 14 patients (two men, 12 women; median age 31.2±5.7 years) with PHPT were evaluated in genetic analysis. Menin gene mutation was found in 3 (21.4%) patients. In overall patients with PHPT (n=361),frequency of MEN-1 (n=3) was evaluated as 0.83%. Genetic analysis of three patients with menin mutation were as follows:

Case 1: A 37-year-old man presented with a history of recurrent nephrolithiasis during 14 years. He was diagnosed as PHPT after biochemical analysis. Genetic analysis was reported as MEN-1:c.643_646delACAG (p.Thr215Serfs*13) heterozygous. Other tumoral components of MEN-1 were not found in physical and laboratory examinations.

Case 2: A 35-year-old man was diagnosed as PHPT and prolactinoma. Genetic analysis was reported as MEN-1: c.654+1G>A heterozygous. He did not have other MEN-1 associated tumors.

Case 3: A 26-year-old woman who had hypoglycemia, hyperammonemia, hyper-insulism, partial empty sella and hyperprolactinemia in her medical history was evaluated. Genetic analysis was associated with heterozygous genomic changes as c984c>a in MEN-1 gene on 7^th exon.

Conclusion: MEN-1 frequency in PHPT patients is estimated as 1–18%. The diagnosis of PHPT is usually made in second decade in MEN-1 patients. So, the guidelines mostly recommend scanning for PHPT before 30 years of age. In our study population, two patients are between ages of 30 and 40 years. It must be kept in mind that the estimated penetrance of 100% is present up to 40–50 years of age in an individual harboring the MEN-1 gene.