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Identification of eight novel SDHB, SDHC, SDHD germline variants in Danish pheochromocytoma/paraganglioma patients.

ABSTRACT: BACKGROUND:Germline mutations in the succinate dehydrogenase complex genes SDHB, SDHC, and SDHD predispose to pheochromocytomas and paragangliomas. Here, we examine the SDHB, SDHC, and SDHD mutation spectrum in the Danish population by screening of 143 Danish pheochromocytoma and paraganglioma patients. METHODS:Mutational screening was performed by Sanger sequencing or next-generation sequencing. The frequencies of variants of unknown clinical significance, e.g. intronic, missense, and synonymous variants, were determined using the Exome Aggregation Consortium database, while the significance of missense mutations was predicted by in silico and loss of heterozygosity analysis when possible. RESULTS:We report 18 germline variants; nine in SDHB, six in SDHC, and three in SDHD. Of these 18 variants, eight are novel. We classify 12 variants as likely pathogenic/pathogenic, one as likely benign, and five as variants of unknown clinical significance. CONCLUSIONS:Identifying and classifying SDHB, SDHC, and SDHD variants present in the Danish population will augment the growing knowledge on variants in these genes and may support future clinical risk assessments.

SUBMITTER: Bennedbæk M

PROVIDER: S-EPMC4898401 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Identification of eight novel SDHB, SDHC, SDHD germline variants in Danish pheochromocytoma/paraganglioma patients.

Bennedbæk Marc M Rossing Maria M Rasmussen Åse K ÅK Gerdes Anne-Marie AM Skytte Anne-Bine AB Jensen Uffe B UB Nielsen Finn C FC Hansen Thomas V O TVO

Hereditary cancer in clinical practice 20160608

<h4>Background</h4>Germline mutations in the succinate dehydrogenase complex genes SDHB, SDHC, and SDHD predispose to pheochromocytomas and paragangliomas. Here, we examine the SDHB, SDHC, and SDHD mutation spectrum in the Danish population by screening of 143 Danish pheochromocytoma and paraganglioma patients.<h4>Methods</h4>Mutational screening was performed by Sanger sequencing or next-generation sequencing. The frequencies of variants of unknown clinical significance, e.g. intronic, missense ...[more]

PMID: 27279923

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Project description:BackgroundPhaeochromocytomas and paragangliomas are neuro-endocrine tumours that occur sporadically and in several hereditary tumour syndromes, including the phaeochromocytoma-paraganglioma syndrome. This syndrome is caused by germline mutations in succinate dehydrogenase B (SDHB), C (SDHC), or D (SDHD) genes. Clinically, the phaeochromocytoma-paraganglioma syndrome is often unrecognised, although 10-30% of apparently sporadic phaeochromocytomas and paragangliomas harbour germline SDH-gene mutations. Despite these figures, the screening of phaeochromocytomas and paragangliomas for mutations in the SDH genes to detect phaeochromocytoma-paraganglioma syndrome is rarely done because of time and financial constraints. We investigated whether SDHB immunohistochemistry could effectively discriminate between SDH-related and non-SDH-related phaeochromocytomas and paragangliomas in large retrospective and prospective tumour series.MethodsImmunohistochemistry for SDHB was done on 220 tumours. Two retrospective series of 175 phaeochromocytomas and paragangliomas with known germline mutation status for phaeochromocytoma-susceptibility or paraganglioma-susceptibility genes were investigated. Additionally, a prospective series of 45 phaeochromocytomas and paragangliomas was investigated for SDHB immunostaining followed by SDHB, SDHC, and SDHD mutation testing.FindingsSDHB protein expression was absent in all 102 phaeochromocytomas and paragangliomas with an SDHB, SDHC, or SDHD mutation, but was present in all 65 paraganglionic tumours related to multiple endocrine neoplasia type 2, von Hippel-Lindau disease, and neurofibromatosis type 1. 47 (89%) of the 53 phaeochromocytomas and paragangliomas with no syndromic germline mutation showed SDHB expression. The sensitivity and specificity of the SDHB immunohistochemistry to detect the presence of an SDH mutation in the prospective series were 100% (95% CI 87-100) and 84% (60-97), respectively.InterpretationPhaeochromocytoma-paraganglioma syndrome can be diagnosed reliably by an immunohistochemical procedure. SDHB, SDHC, and SDHD germline mutation testing is indicated only in patients with SDHB-negative tumours. SDHB immunohistochemistry on phaeochromocytomas and paragangliomas could improve the diagnosis of phaeochromocytoma-paraganglioma syndrome.FundingThe Netherlands Organisation for Scientific Research, Dutch Cancer Society, Vanderes Foundation, Association pour la Recherche contre le Cancer, Institut National de la Santé et de la Recherche Médicale, and a PHRC grant COMETE 3 for the COMETE network.

Project description:Pheochromocytoma and paragangliomas (PPGLs) are rare neuroendocrine tumors carrying 25-40% pathogenic germline gene variants (PGVs). We evaluated clinical, laboratory, and germline molecular profile of 115 patients with pathologic (14 patients were relatives from 8 different families recruited for genetic survey) confirmed PPGL followed in our institution. Patients with classic MEN2A/MEN2B phenotypes and at-risk relatives underwent direct analysis of RET proto-oncogene, and the remaining had samples submitted to complete next-generation sequencing aiming 23 PPGL-related genes: ATM, ATR, CDKN2A, EGLN1, FH, HRAS, KIF1B, KMT2D, MAX, MDH2, MERTK, MET, NF1, PIK3CA, RET, SDHA, SDHAF2, SDHB, SDHC, SDHD, TMEM127, TP53, and VHL. We also developed a clinical judgment score (CJS) to determine the probability of patients having a potentially hereditary disease. The resulting genetic landscape showed that 67 patients (58.3%) had variants in at least one gene: 34 (50.7%) had exclusively pathogenic or likely pathogenic variants, 13 (19.4%) had pathogenic or likely pathogenic variants and variant of undetermined significance (VUS), and 20 (29.8%) carried only VUS. PGVs were found in RET (n = 18; 38.3%), VHL (n = 10; 21.3%), SDHB and NF1 (n = 8; 17% each), and MAX, SDHD, TMEM127, and TP53 (n = 1; 2.1% each). Direct genetic testing disclosed 91.3% sensitivity, 81.2% specificity, and 76.4% and 93.3% positive predictive value (PPV) and negative predictive values (NPV), respectively. The CJS to identify patients who would not benefit from genetic testing had 75% sensitivity, 96.4% specificity, and 60% and 98.2% PPV and NPV, respectively. In summary, the landscape of PPGL germline gene variants from 115 Brazilian patients resulted in slightly higher prevalent pathogenic and likely pathogenic variants, especially in the RET gene. We suggest a CJS to identify PPGL patients who would not require initial genetic evaluation, improving test specificity and reducing costs.

Dataset Information

Identification of eight novel SDHB, SDHC, SDHD germline variants in Danish pheochromocytoma/paraganglioma patients.

Publications

Identification of eight novel SDHB, SDHC, SDHD germline variants in Danish pheochromocytoma/paraganglioma patients.

Similar Datasets

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