Context: Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant disease caused by mutations in the MEN1 gene. MEN1 is characterized by a broad spectrum of clinical manifestations, of which the most frequent are primary hyperparathyroidism, pituitary adenomas, and neuroendocrine tumors. MEN1 presents a broad spectrum of variants, including large deletions, and truncating, missense, or splicing point mutations. The genotype-phenotype relationship remains under debate. The age-dependent penetrance and the variability of intra- and inter-familial expression of the disease increase the difficulty of interpretation of non-truncating variants in the MEN1 gene, particularly regarding sporadic patients with incomplete diagnosis criteria.
Patients and Methods: The TENGEN network (French oncogenetics network of neuroendocrine tumors) has interpreted and collected all allelic variants and clinical characteristics of the MEN1-positive patients, identified through genetic testing performed in France from 1997 to 2015. We analyzed the clinical and genetic characteristics of patients from the UMD-MEN1 database cohort.
Results: 370 distinct variants reported in 1,676 patients have currently been registered. This database analysis pointed out the low frequency of benign or likely benign missense variants in MEN1 (only 6.6%). Eight families (1.9%) presented a familial isolated hyperparathyroidism and harbored the same mutation found in authentic MEN1-families. An association exists between large rearrangements and an earlier onset of the disease, whereas no difference was observed between truncating and non-truncating variants.
Conclusion: All variants were registered in a locus-specific database called the UMD-MEN1 database (www.umd.be/MEN1/), which provides an exhaustive overview of the MEN1 variants present in the French population. For each variant, a classification based on the clinical data collection from patients and a standardized analysis is publicly available. Clinical data collections allow the determination of genotype-phenotype correlation and age-related penetrance of lesions in the cohort.
18 - 21 May 2019
European Society of Endocrinology