Cell
Volume 61, Issue 6, 15 June 1990, Pages 931-937
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Article
Myoclonic epilepsy and ragged-red fiber disease (MERRF) is associated with a mitochondrial DNA tRNALys mutation

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Abstract

An A to G transition mutation at nucleotide pair 8344 in human mitochondrial DNA (mtDNA) has been identified as the cause of MERRF. The mutation alters the TψC loop of the tRNALys gene and creates a CviJI restriction site, providing a simple molecular diagnostic test for the disease. This mutation was present in three independent MERRF pedigrees and absent in 75 controls, altered a conserved nucleotide, and was heteroplasmic. All MERRF patients and their less-affected maternal relatives had between 2% and 27% wild-type mtDNAs and showed an age-related association between genotype and phenotype. This suggests that a small percentage of normal mtDNAs has a large protective effect on phenotype. This mutation provides molecular confirmation that some forms of epilepsy are the result of deficiencies in mitochondrial energy production.

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  • Cited by (0)

    Present address: Dipartimento di Biochemica e Molecolare, Università di Bari, 70126 Bari, Italy.

    §

    Present address: Fachbereich Chemie der Phillips-Universität Marburg (Lahn), Marburg, Federal Republic of Germany.

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