(mentions CMT) Episodic ataxia and hemiplegia caused by the 8993TC mitochondrial

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Journal of Medical Genetics 2007;44:797-799

Episodic ataxia and hemiplegia caused by the 8993TC mitochondrial

DNA mutation

K Craig1, H R Elliott1, S M Keers1, C Lambert1, A Pyle1, T D

Graves2, C Woodward2, M G Sweeney2, M B 2, M G Hanna2, P F

Chinnery1,3

1 Mitochondrial Research Group, Institute of Neurology, Queen

Square, London, UK

2 Department of Molecular Neuroscience, Institute of Neurology,

Queen Square, London, UK

3 Institute of Human Genetics, Newcastle University, UK

ABSTRACT

The m.8993TC MTATP6 mutation of mitochondrial DNA (mtDNA) usually

causes mitochondrial disease in childhood, but was recently

described in a family with adult onset ataxia and polyneuropathy.

Cytochrome c oxidase muscle histochemistry, which is the standard

clinical investigation for mitochondrial disease in adults, is

usually normal in patients with MTATP6 mutations. This raises the

possibility that these cases have been missed in the past. We

therefore studied 308 patients with unexplained ataxia and 96

patients with suspected Charcot–Marie–Tooth disease to determine

whether the m.8993TC MTATP6 mutation is common in unexplained

inherited ataxia and/or polyneuropathy.

We identified a three-generation family with the m.8993TC mutation

of mtDNA. One subject had episodic ataxia (EA) and transient

hemipareses, broadening the phenotype. However, no further cases

were identified in an additional cohort of 191 patients with

suspected EA.

In conclusion, m.8993TC MTATP6 should be considered in patients with

unexplained ataxia, CMT or EA, but cases are uncommon.