A novel m.7539C>T point mutation in the mt-tRNA(Asp) gene associated with multisystemic mitochondrial disease.
Bottom Line: Mitochondrial transfer RNA (mt-tRNA) mutations are the commonest sub-type of mitochondrial (mtDNA) mutations associated with human disease.To date only three mt-tRNA(Asp) gene mutations have been described with clear evidence of pathogenicity.The novel m.7539C>T mt-tRNA(Asp) gene mutation extends the spectrum of pathogenic mutations in this gene, further supporting the notion that mt-tRNA(Asp) gene mutations are associated with multisystemic disease presentations.
Affiliation: Department of Neurology, University of Halle-Wittenberg, Ernst-Grube-Str. 40, Halle/Saale 06097, Germany.Show MeSH
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Mentions: Neurological examination revealed pathological laughter and crying, dysarthric speech, proximal accentuated paresis (MRC 4/5), hammer toes and talipes cavus. Arm deep tendon reflex zones were broadened with exhaustible ankle clonus on both sides. Pallhypesthesia of the lower distal extremity has been examined. Romberg test revealed loss of stand. Unterberger's test showed undirected falling tendency. Electroencephalogram revealed multifocal reliable signs of increased cerebral excitability. Needle electromyogram of the brachioradialis muscle revealed distinctive myopathic changes and nerve conduction studies of the tibialis nerve showed an indication for a mixed motoric neuropathy. Sensory neurography was normal. Audiogram revealed severe bilateral inner ear hearing loss on both sides. Ophthalmologic examination showed a regenerative post-cataract on both eyes. Neuropsychological testing revealed severely restricted information processing and instructional understanding. Minimental state examination, however, showed normal results. cMRI showed generalised brain volume reduction (Fig. 1A). Resting lactate levels were normal but mildly elevated in a validated bicycle exercise test (after 10 minutes cycling on 30 Watt 3.9 mmol/l, normal: <2.0) . Creatine kinase was elevated up to 15.2 µmol/l (normal: <2.4) in multiple samples taken at different time points.
Affiliation: Department of Neurology, University of Halle-Wittenberg, Ernst-Grube-Str. 40, Halle/Saale 06097, Germany.