Improving the diagnosis of cobalamin and related defects by genomic analysis, plus functional and structural assessment of novel variants

Autor: Brasil, Sandra, Leal, Fátima, Vega, Ana, Navarrete, Rosa, Ecay, María Jesús, Desviat, Lourdes R., Riera, Casandra, Padilla, Natàlia, de la Cruz, Xavier, Couce, Maria Luz, Martin-Hernández, Elena, Morais, Ana, Pedrón, Consuelo, Peña-Quintana, Luis, Rigoldi, Miriam, Specola, Norma, de Almeida, Isabel Tavares, Vives, Inmaculada, Yahyaoui, Raquel, Rodríguez-Pombo, Pilar, Ugarte, Magdalena, Pérez-Cerdá, Celia, Merinero, Begoña, Pérez, Belén, Universitat Autònoma de Barcelona
Přispěvatelé: UAM. Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CBM), Instituto de Investigación Sanitaria Hospital Universitario de La Paz (IdiPAZ), Fundación Ramón Areces, Fundación Isabel Gemio, La Caixa, European Commission
Rok vydání: 2018
Předmět:
Zdroj: Biblos-e Archivo. Repositorio Institucional de la UAM
instname
Dipòsit Digital de Documents de la UAB
Universitat Autònoma de Barcelona
Digital.CSIC. Repositorio Institucional del CSIC
Orphanet Journal of Rare Diseases
Repositorio Institucional de la Consejería de Sanidad de la Comunidad de Madrid
Consejería de Sanidad de la Comunidad de Madrid
Orphanet Journal of Rare Diseases, Vol 13, Iss 1, Pp 1-12 (2018)
Popis: [Background] Cellular cobalamin defects are a locus and allelic heterogeneous disorder. The gold standard for coming to genetic diagnoses of cobalamin defects has for some time been gene-by-gene Sanger sequencing of individual DNA fragments. Enzymatic and cellular methods are employed before such sequencing to help in the selection of the gene defects to be sought, but this is time-consuming and laborious. Furthermore some cases remain undiagnosed because no biochemical methods have been available to test for cobalamin absorption and transport defects.
[Results] This paper reports the use of massive parallel sequencing of DNA (exome analysis) for the accurate and rapid genetic diagnosis of cobalamin-related defects in a cohort of affected patients. The method was first validated in an initial cohort with different cobalamin defects. Mendelian segregation, the frequency of mutations, and the comprehensive structural and functional analysis of gene variants, identified disease-causing mutations in 12 genes involved in the absorption and synthesis of active cofactors of vitamin B12 (22 cases), and in the non-cobalamin metabolism-related genes ACSF3 (in four biochemically misdiagnosed patients) and SUCLA2 (in one patient with an unusual presentation). We have identified thirteen new variants all classified as pathogenic according to the ACGM recommendation but four were classified as variant likely pathogenic in MUT and SUCLA2. Functional and structural analysis provided evidences to classify them as pathogenic variants.
[Conclusions] The present findings suggest that the technology used is sufficiently sensitive and specific, and the results it provides sufficiently reproducible, to recommend its use as a second-tier test after the biochemical detection of cobalamin disorder markers in the first days of life. However, for accurate diagnoses to be made, biochemical and functional tests that allow comprehensive clinical phenotyping are also needed.
An institutional grant from the Fundación Ramón Areces to the Centro de Biología Molecular Severo Ochoa, and funding from the European Regional Development Fund, are gratefully acknowledged.This work was funded by grants PI13/01239-PI16/00573; Fundación Isabel Gemio-Fundación La Caixa (LCF/PR/PR16/11110018)
Databáze: OpenAIRE
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