Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.
Rui M B Maciel, Cleber P Camacho, Lígia V M Assumpção, Natassia E Bufalo, André L Carvalho, Gisah A de Carvalho, Luciana A Castroneves, Francisco M de Castro Jr, Lucieli Ceolin, Janete M Cerutti, Rossana Corbo, Tânia M B L Ferraz, Carla V Ferreira, M Inez C França, Henrique C R Galvão, Fausto Germano-Neto, Hans Graf, Alexander A L Jorge, Ilda S Kunii, Márcio W Lauria, Vera L G Leal, Susan C Lindsey, Delmar M Lourenço Jr, Léa M Z Maciel, Patrícia K R Magalhães, João R M Martins, M Cecília Martins-Costa, Gláucia M F S Mazeto, Anelise I Impellizzeri, Célia R Nogueira, Edenir I Palmero, Cencita H C N Pessoa, Bibiana Prada, Débora R Siqueira, Maria Sharmila A Sousa, Rodrigo A Toledo, Flávia O F Valente, Fernanda Vaisman, Laura S Ward, Shana S Weber, Rita V Weiss, Ji H Yang, Magnus R Dias-da-Silva, Ana O Hoff, Sergio P A Toledo and Ana L Maia
Louise Vølund Larsen, Delphine Mirebeau-Prunier, Tsuneo Imai, Cristina Alvarez-Escola, Kornelia Hasse-Lazar, Simona Censi, Luciana A Castroneves, Akihiro Sakurai, Minoru Kihara, Kiyomi Horiuchi, Véronique Dorine Barbu, Francoise Borson-Chazot, Anne-Paule Gimenez-Roqueplo, Pascal Pigny, Stephane Pinson, Nelson Wohllk, Charis Eng, Berna Imge Aydogan, Dhananjaya Saranath, Sarka Dvorakova, Frederic Castinetti, Attila Patocs, Damijan Bergant, Thera P Links, Mariola Peczkowska, Ana O Hoff, Caterina Mian, Trisha Dwight, Barbara Jarzab, Hartmut P H Neumann, Mercedes Robledo, Shinya Uchino, Anne Barlier, Christian Godballe and Jes Sloth Mathiesen
Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.
Design and methods
An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017.
Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4–1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis.
Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.