A novel mutation in the mitochondrial tRNA Asn gene associated with a lethal disease
Laurent Coulbault1, Danielle Herlicoviez, Françoise Chapon
1Laboratoire de Biochimie A, Centre Hospitalier et Universitaire de Caen, Avenue Côte de Nacre, 14033 Caen cedex, France.
Abstract:
We describe a lethal mitochondrial disease in a 10-month-old child who presented with encephalomyopathy. Histochemical and electron microscopy examinations of skeletal muscle biopsy revealed abnormal mitochondria associated with a combined deficiency of complexes I and IV. After excluding mitochondrial DNA deletions and depletion, direct sequencing was used to screen for mutation in all transfer RNA (tRNA) genes. A T-to-C substitution at position 5693 in the tRNA(Asn) gene was found in blood and muscle. Microdissection of muscle biopsy and its analysis revealed the highest level of this mutation in cytochrome c oxidase (COX)-negative fibres. We suggest that this novel mutation would affect the anticodon loop structure of the tRNA(Asn) and cause a fatal mitochondrial disease.
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