A mitochondrial DNA tRNA(Val) point mutation associated with adult-onset Leigh syndrome
R M Chalmers1, P J Lamont, I Nelson
1Neurogenetics Section, University Department of Clinical Neurology, Queen Square, London, UK.
Abstract:
Subacute necrotizing encephalomyelopathy (Leigh syndrome) is associated with a number of mitochondrial DNA (mtDNA) abnormalities. We studied a family with maternally inherited encephalomyelopathy. Two siblings developed adult-onset Leigh syndrome. Muscle biopsy specimens showed enhanced succinic dehydrogenase activity and cytochrome oxidase-negative fibers. We sequenced the ATPase- and transfer RNA (tRNA)-encoding genes of mtDNA and identified a novel mtDNA valine tRNA mutation at base pair 1644. This transversion was heteroplasmic in blood and muscle in all individuals studied, and the proportion of mutant mtDNA correlated with disease severity. This is the first heteroplasmic transversion within a mtDNA tRNA gene and the second pathogenic mtDNA tRNA(Val) mutation to be associated with human disease.
Related Concept Videos
Mutations
Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Animal Mitochondrial Genetics
ATP Synthase: Mechanism
ATP Synthase: Structure
Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life


