Open AccessA novel hypomorphic splice variant in EIF2B5 gene is associated with mild ovarioleukodystrophy
Author(s) -
RodríguezPalmero Agustí,
Schlüter Agatha,
Verdura Edgard,
Ruiz Montserrat,
Martínez Juan José,
Gourlaouen Isabelle,
Ka Chandran,
Lobato Ricardo,
Casasnovas Carlos,
Le Gac Gérald,
Fourcade Stéphane,
Pujol Aurora
Publication year - 2020
Publication title -
annals of clinical and translational neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.824
H-Index - 42
ISSN - 2328-9503
DOI - 10.1002/acn3.51131
Subject(s) - minigene , rna splicing , mutation , gene isoform , genetics , peripheral blood mononuclear cell , gene , intron , splice , phenotype , biology , alternative splicing , splice site mutation , allele , medicine , microbiology and biotechnology , rna , in vitro
Objective To identify the genetic cause in an adult ovarioleukodystrophy patient resistant to diagnosis. Methods We applied whole‐exome sequencing (WES) to a vanishing white matter disease patient associated with premature ovarian failure at 26 years of age. We functionally tested an intronic variant by RT‐PCR on patient’s peripheral blood mononuclear cells (PBMC) and by minigene splicing assay. Results WES analysis identified two novel variants in the EIF2B5 gene: c.725A > G (p.Tyr242Cys) and an intronic noncanonical mutation (c.1156 + 13G>A). This intronic mutation resulted into generation of various isoforms both in patient’s PBMC and in the minigene splicing assay, showing that ~20% residual wild‐type isoform is still expressed by the intronic‐mutated allele alone, concordant with an hypomorphic effect of this variant. Conclusion We report two novel variants in EIF2B5 , one of them a noncanonical intronic splice variant, located at a +13 intronic position. This position is mutated only in 0.05% of ClinVar intronic mutations described so far. Furthermore, we illustrate how minigene splicing assay may be advantageous when validating splice‐altering variants, in this case highlighting the coexistence of wild‐type and mutated forms, probably explaining this patient’s milder, late‐onset phenotype.