Identification of the novel mutation m.5658T>C in the mitochondrial tRNA(Asn) gene in a patient with myopathy, bilateral ptosis and ophthalmoparesis

Tomàs Pinós, Maria Jesús Melià, Nicolau Ortiz, Albert Martinez-Vea, Antoni Raventós-Estellé, Eduard Gallardo, Javier Hernández-Losa, Yolanda Cámara, Antoni L. Andreu, Elena García-Arumí

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    4 Citations (Scopus)

    Abstract

    We report a heteroplasmic novel mutation m.5658T>C in the mt-tRNAAsn gene in a patient who initially presented myopathy, bilateral ptosis and ophthalmoparesis and several years later developed a non-nephrotic proteinuria. The muscle biopsy showed cytochrome c oxidase (COX) negative and ragged red fibers and in the kidney biopsy that was taken in order to identify the causes of non-nephrotic proteinuria, a focal segmental glomerulosclerosis was observed. Using laser capture microdissection we isolated COX negative fibers and COX positive fibers from the muscle of the patient and determined that there was a clear increase in the mutation load in the COX negative muscle fibers. However, the low degree of mutation load found in the renal biopsy of the patient does not allow us to conclude that the m.5658T>C mutation is responsible for focal glomerulosclerosis. Additionally, we hypothesize that the mutated m.5658T nucleotide might be structurally relevant, as it is one of the fifteen nucleotides conserved in all the species analyzed and is situated contiguously to the discriminator base in the 3'end of the mt-tRNA, where the tRNase Z cleaves the 3' trailer sequence during mt-tRNA maturation. © 2013 Elsevier B.V.
    Original languageEnglish
    Pages (from-to)330-336
    JournalNeuromuscular Disorders
    Volume23
    Issue number4
    DOIs
    Publication statusPublished - 1 Apr 2013

    Keywords

    • Laser capture microdissection
    • Mitochondria
    • Mt-tRNA (Asn)
    • Myopathy

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