LEBER'S HEREDITARY OPTIC NEUROPATHY (LHON): A GLOBAL COMPARISON WITH SPECIAL EMPHASIS ON INDIA

Leber’s hereditary optic neuropathy (LHON) is a rare mitochondrial genetic disorder, which is characterized by acute to subacute painless loss of central vision in young adult males. It is caused by a point mutation of mitochondrial DNA, which includes m. 11778G>A, m.3460G>A, m. and m. 14484T>C, resulting in retinal ganglion cell loss due to optic neuropathy. The prevalence of LHON worldwide is considerably variable due to genetic predisposition, geographical factors, and technical factors. In India, LHON is believed to be underdiagnosed and underreported compared to Western and East Asian nations. Also, Limited Availability of physician awareness in LHON can lead to a delay in diagnosis. Data collected in India shows a relatively high prevalence of sporadic cases and different mutations, of which m. 11778G>a is the predominant mutation. Environmental factors such as alcohol and cigarette use, nutritional deficiencies, and toxic exposures could also affect LHON and impact affected individuals in India. By contrast, the prevalence of better epidemiological data is observed in Japan, China, Europe, and the United States owing to the presence of genetic screening programs and patient registries. Japan has a relatively higher prevalence of m.11778G>A mutations, and European cohorts have a better rate of visual recovery owing to early intervention and treatment with odobenine and novel gene therapies based on adeno-associated virus vectors. In general, though LOHN is a worldwide phenomenon, there are considerable variations between Indian and international cases recording diagnosis, handling, and advancement in research. Enhancement in genetic lab facilities, awareness among doctors, and availability of new treatment are needed for improving the present status of LOHN in India.