Leber hereditary optic neuropathy (LHON) is a maternally inherited disease caused by mitochondrial DNA (mtDNA) mutation with the common mutation sites of m. 3460 G>A, m.11778 G>A and m. 14484 T>C, and other mutation sites are rare.Understanding the mutation type of mtDNA in LHON patients has an important clinical significance.

This study was to analyze the clinical features of LHON and detect the mitochondrial mutation.

Twelve unrelated Chinese patients who was diagnosed as LHON were included in Peking University People's Hospital from 2010 to 2014.The visual acuity, perimetry, ocular segment, visual evoked potential, fundus were binocularly examined.The peripheral blood of 4 ml was collected from each patient and mtDNA was amplified and sequenced by using PCR.Three common genetic mutation sites for LHON and other mutation sites were determined and analyzed.This study protocol was approved by Ethic Committee of Peking University People's Hospital and complied with Helsinki Declaration.Written informed consent was obtained from each patient prior to any medical examination.

Of the 12 patients, 11 were male and 1 was female.The visual acuity of both eyes reduced simultaneously in 7 patients, and the visual acuity of left eye and the right eye first reduced in 3 patients and 1 patient, respectively.There was no significant correlation in the visual impairment between the left and right eyes (P>0.05). In the near vision of the patients, J7 was invisible in 18 eyes, and J7 were obtained in 3 eyes, J6 were obtained in 2 eyes and J2 was obtained in 1 eye.In the distant vision of the patients, hand movement was obtained in 1 eye, light perception was obtained in 1 eye, 0.01-0.1 were obtained in 18 eyes and 0.12-0.3 were obtained in 2 eyes.The visual field defect of nasal lateral was found in 7 eyes, visual field defect of temporal lateral was found in 3 eyes and the visual field defect of central was found in 8 eyes.mtDNA sequencing revealed that m. 3460 G>A mutation was seen in 3 patients, m.11778 G>A mutation was seen in 5 patients and m. 14484 T>C mutation was seen in 2 patients.In addition, other 2 mutations were found in 2 patients, which were m. 3497 C>T and m. 10663 T>C mutations at the MT-ND1 and MT-ND4L genes, respectively.

LHON is more common in male.Visual impairment shows the varying degrees between both eyes of patients and appears to be severe in near vision.Central visual field defect is common in LHON patients.This study detects m. 3497 C>T and m. 10663 T>C mutation in Chinese LHON patients.

Mitochondrial disease; DNA mutational analysis; Genetics; Optic atrophies, genetic; Polymerase chain reaction; Leber hereditary optic neuropathy; Vision