Demographics of a Large International Population of Patients Affected by Leber's Hereditary Optic Neuropathy.

PURPOSE: To study the demographics of Leber's hereditary optic neuropathy (LHON) using a large international database of people affected by LHON.

DESIGN: Cross-sectional study.

PARTICIPANTS: One thousand five hundred seventeen people affected by LHON with a known pathogenic genetic mutation.

METHODS: Self-reported genetic and demographic data were collected. The data were de-identified and then analyzed.

MAIN OUTCOME MEASURES: Leber's hereditary optic neuropathy mutation, gender, age at vision loss onset, and geographical region.

RESULTS: The data showed that both females and males can experience symptom onset at any age. We found a 3:1 male-to-female ratio. Interestingly, at younger than 5 years and older than 45 years, the male-to-female ratio of those becoming affected was approximately 1:1. A dramatic peak in age at onset of vision loss was found among males between 14 and 26 years of age. Disease onset in females occurred across all age groups, without any comparable dramatic peak of onset age. This study found that 10% of individuals become affected with LHON after 50 years of age. According to the literature, we found that the m.11778, m.14484, and m.3460 mutations were the most common LHON point mutations in both males and females, with a similar age at onset distribution.

CONCLUSIONS: This was the largest study of LHON demographics to date. It showed that women carrying an LHON mutation are at higher risk of losing vision than is generally expected. Unlike the traditional 5:1 male-to-female ratio commonly reported in the literature, we found a 3:1 male-to-female ratio. Earlier studies may have harbored an ascertainment bias of overemphasizing the confirmation of this being a disease of young men. However, our data suggest that LHON is a disease that affects both females and males of all ages. This should prompt physicians to conduct genetic testing for LHON in all patients who meet the clinical criteria, regardless of whether they fit the demographics traditionally associated with the disease. Counseling about LHON should be offered to all maternal bloodline relatives, females and males of all ages, because they are at risk of sudden-onset legal blindness.