Frequency of primary mutations of Leber's hereditary optic neuropathy patients in North Indian population.

Purpose: Leber's hereditary optic neuropathy (LHON) is an inherited optic neuropathy characterized by subacute painless vision loss. The majority of LHON is caused due to one of the three primary mutations in the mitochondrial DNA (m.G3460A, m.G11778A, and m.T14484C). The frequency of these mutations differs in different populations. The purpose of this study is to observe the frequency of three common primary mutations in the North Indian population.

Methods: Forty LHON patients within the age group of 10-50 years underwent molecular testing for primary mutations. For two patients, testing for mother and other siblings was also carried out, using bidirectional sequencing.

Results: A total of 11 out of 40 (27.5%) patients were found to be carrying m.G11778A mutation. Siblings of two probands were also positive for the same mutation. In one family, two primary mutations (m.G11778A and m.T14484C) were found in the proband and in the mother as well.

Conclusion: In this study, 27.5% mutation was detected in North Indian LHON families. These results suggest that m.G11778A mutation is more frequent in this population. The results of the present study are compatible with studies of an Asian population and Northern European population.