True MEN1 or phenocopy? Evidence for geno-phenotypic correlations in MEN1 syndrome

• Published in: Endocrine Vol. 65; no. 2; pp. 451 - 459
• Main Authors: Kövesdi, Annamária, Tóth, Miklós, Butz, Henriett, Szücs, Nikolette, Sármán, Beatrix, Pusztai, Péter, Tőke, Judit, Reismann, Péter, Fáklya, Mónika, Tóth, Géza, Somogyi, Anikó, Borka, Katalin, Erdei, Annamária, Nagy, Endre V., Deák, Veronika, Valkusz, Zsuzsanna, Igaz, Péter, Patócs, Attila, Grolmusz, Vince Kornél
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2019; Springer Nature B.V
• Subjects: Adult; Age of Onset; Aged; Diabetes; DNA Mutational Analysis; Endocrinology; Female; Frameshift mutation; Genetic Association Studies; Genetic screening; Genetic Testing; Genotype & phenotype; Genotypes; Humanities and Social Sciences; Humans; Hungary - epidemiology; Incidence; Internal Medicine; Male; Medicine; Medicine & Public Health; Middle Aged; multidisciplinary; Multiple endocrine neoplasia; Multiple Endocrine Neoplasia Type 1 - epidemiology; Multiple Endocrine Neoplasia Type 1 - genetics; Mutation; Neuroendocrine tumors; Original; Original Article; Penetrance; Phenotypes; Proto-Oncogene Proteins - genetics; Retrospective Studies; Science; Tumors; Hungary; Phenocopy; Multiple endocrine neoplasia type 1; Gastroenteropancreatic neuroendocrine tumor; Genotype–phenotype associations; Neuroendocrine tumors
• DOI: 10.1007/s12020-019-01932-x
• ISSN: 1355-008X

Purpose Multiple endocrine neoplasia type 1 is a rare tumor syndrome caused by germline mutations of MEN1 gene. Phenotype varies widely, and no definitive correlation with the genotype has been observed. Mutation-negative patients with MEN1-associated tumors represent phenocopies. By comparing mutation-positive and mutation-negative patients, we aimed to identify phenotype features predictive for a positive genetic test and to evaluate the role of MEN1 mutations in phenotype modulation. Methods Mutation screeening of MEN1 gene by Sanger sequencing and assessment of clinical data of 189 consecutively enrolled probands and relatives were performed at our national and European Reference Center. Multiple ligation probe amplification analysis of MEN1 gene and Sanger sequencing of CDKN1B were carried out in clinically suspicious but MEN1 -negative cases. Results Twenty-seven probands and twenty family members carried MEN1 mutations. Five mutations have not been described earlier. Pronouncedly high number of phenocopies (>70%) was observed. Clinical suspicion of MEN1 syndrome emerged at significantly earlier age in MEN1 -positive compared to MEN1 -negative probands. Gastroenteropancreatic neuroendocrine tumors developed significantly earlier and more frequently in carriers compared to non-carriers. Probands with high-impact (frameshift, nonsense, large deletions) mutations, predicted to affect menin function significantly, developed GEP-NETs more frequently compared to low-impact (inframe and missense) mutation carriers. Conclusions MEN1 phenocopy is common and represents a significant confounder for the genetic testing. GEP-NET under 30 years best predicted a MEN1 mutation. The present study thus confirmed a previous proposal and suggested that GEP-NET under 30 years should be considered as a part of the indication criteria for MEN1 mutational analysis.