Vitamin B12 in Leber hereditary optic neuropathy mutation carriers: a prospective cohort study.

The high prevalence of vitamin B12 deficiency in LHON mutation carriers, both asymptomatic mutation carriers and LHON patients, highlights the need for regular vitamin B12 screening in this population, in order to ensure early treatment, aiming for better outcomes. Our study is not conclusive regarding vitamin B12 deficiency as determinant for disease conversion in LHON, and further research is warranted to disentangle the role of vitamin B12 in the pathophysiology and prognosis of LHON.