Leber's hereditary optic neuropathy: Heteroplasmy is likely to be significant in the expression of LHON in families with the 3460 ND1 mutation

Aim-To assess the effect of heteroplasmy on the expression of Leber's hereditary optic neuropathy (LHON) in a large family with the 3460 LHON mutation. Methods-A Mutation detection was performed by restriction enzyme digestion of polymerase chain reaction (PCR) products. Heteroplasmy was estimated by quantitation of wild type:mutant product ratios. Results-There is a significant association between levels of mutant mtDNA and manifestation of the disease phenotype. Conclusion-As a high proportion of families with the 3460 mutation demonstrate heteroplasmy; this is likely to be a significant factor in disease expression.