Designation criteria for Leber's hereditary optic neuropathy

Designation criteria for Leber's hereditary optic neuropathy (LHON) have been established by a working group for retino-choroidal and optic atrophy funded by the Ministry of Health, Labor, and Welfare (MHLW) of Japan in collaboration with the Japanese Neuro-ophthalmology Society. The criteria are composed of three major symptoms and three ancillary test findings. According to the number and the combination of these symptoms and findings, subjects are classified into definite, probable, and possible LHON cases and asymptomatic carriers. The major symptoms include bilateral involvement with a time-lag, a papillomacular bundle atrophy, both characteristic optic disc findings at the acute phase. In the ancillary testings, mitochondrial DNA mutations specific for LHON are detailed with a table listing the mutation loci being attached. To enhance readers' understanding of description of the major symptoms and ancillary test findings, explanatory remarks on 11 parameters are supplemented. The establishment of the criteria facilitates epidemiological survey of LHON by MHLW and contributes to improvement of welfare for patients with LHON in Japan.