Mitochondrial tRNAThr 15891C>G mutation was not associated with Leber's hereditary optic neuropathy in Han Chinese patients.

Mutations in mitochondrial DNA (mtDNA) were the most important causes of Leber's hereditary optic neuropathy (LHON). To date, approximately 25 LHON-associated mtDNA mutations have been identified in various ethnic populations. Three primary mutations, the 3460G > A, 11778G > A and 14484T > C, in genes encoding the subunits of respiratory chain complex I, were the most common LHON-associated mtDNA mutations. Moreover, secondary mutations in mt-tRNA genes have been reported increasingly to be associated with LHON, simply due to the high mutation rates of mt-tRNAs. There is a lack of functional analysis and a poor genetic evaluation of a certain mt-tRNA mutation, which failed to meet the classic pathogenicity scoring system. As a result, how to classify a pathogenic mutation in mt-tRNA gene became important for both geneticist and clinician to diagnosis the LHON or the suspicious of LHON. In this study, we reassessed the role of a point mutation in mt-tRNA(Thr) gene which had been reported to be a mutation associated with LHON, the pathogenicity of this mutation has been discussed in this context.