Gene-environment interactions in Leber hereditary optic neuropathy.

Area of Science:

• Genetics
• Ophthalmology
• Epidemiology

Background:

• Leber hereditary optic neuropathy (LHON) is a genetic disorder caused by mitochondrial DNA (mtDNA) mutations.
• Environmental factors are suspected to trigger vision loss in LHON, but evidence is limited.
• Identifying environmental triggers is crucial for LHON prevention and potential therapeutic strategies.

Purpose of the Study:

• To investigate the association between environmental factors and visual failure in Leber hereditary optic neuropathy.
• To determine the clinical penetrance of primary LHON mtDNA mutations in relation to lifestyle factors.

Main Methods:

• A large, multicenter epidemiological study involving 196 affected and 206 unaffected carriers from 125 LHON pedigrees.
• Collected data on exposure to smoking, alcohol, and other environmental factors using a structured questionnaire.
• Focused on three primary pathogenic mtDNA mutations: m.3460G>A, m.11778G>A, and m.14484T>C.

Main Results:

• A strong, consistent association was found between smoking and vision loss in LHON patients, independent of gender and alcohol intake.
• Clinical penetrance reached 93% in male smokers with LHON.
• A trend towards increased visual failure was observed with heavy alcohol consumption.

Conclusions:

• Smoking is a significant environmental trigger for visual failure in individuals with Leber hereditary optic neuropathy.
• Asymptomatic carriers of LHON mtDNA mutations should be strongly advised to cease smoking and moderate alcohol intake.
• These findings highlight the importance of lifestyle modifications for LHON disease prevention.