Variable phenotype including Leigh syndrome with a 9185T>C mutation in the MTATP6 gene.

We describe 15 members of a Caucasian family with an apparently homoplasmic T -> C mutation at nucleotide position 9185 (9185T>C) in the mtDNA encoded MTATP6 (ATPase 6) gene. The clinical phenotype is extremely variable and includes late-onset Leigh syndrome (LS), isolated demyelinating peripheral neuropathy and neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP). Following recent reports of this same mutation in a single case and in a family with late-onset LS and NARP-like features, our paper emphasises the role of MTATP6 in LS and expands the associated clinical phenotype further.