Mitochondrial DNA analyses were carried out on 30 individuals with clinically documented or suspected Leber's hereditary optic neuropathy (LHON). Three methods based on the polymerase chain reaction (PCR) were compared, all three aiming at detecting the G/C to A/T mutation of base pair 11,778 causing LHON. Two methods included restriction analysis with either Sfa NI or Mae III, while the third one relied on allele-specific amplification (ASA), using a mutation-specific primer. The results were completely consistent, showing the presence of the mutation in 18 and its absence in 12 cases. From these results it is concluded, that mutation-specific PCR is the diagnostic method of choice, because it obviates the need for subsequent restriction analysis, thus being faster and more cost-efficient. The general applicability of ASA makes this strategy universally useful for detection of specific mutations in the diagnostic analysis of genetic disease, and for typing of genetic polymorphisms or other sequence variations due to single-base differences.