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A case of late‐onset Leber's hereditary optic neuropathy with elevated serum lactic acid and pyruvic acid levels by cycle ergometer exercise
Author(s) -
Hao Akihito,
Hideyama Takuto,
Katsumata Junko,
Seki Tomonari,
Tanaka Masaki,
Yamagami Akiko,
Shimizu Jun,
Shiio Yasushi
Publication year - 2018
Publication title -
neurology and clinical neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
0ISSN - 2049-4173
DOI - 10.1111/ncn3.12219
Subject(s) - medicine , subclinical infection , optic neuropathy , mitochondrial dna , leber's hereditary optic neuropathy , endocrinology , asymptomatic , peripheral neuropathy , cardiology , skeletal muscle , gastroenterology , pathology , genetics , ophthalmology , diabetes mellitus , gene , biology , optic nerve
Abstract Leber's hereditary optic neuropathy ( LHON ) is a mitochondrial disorder characterized by acute or subacute bilateral vision loss. We describe a female who experienced visual impairment at the age of 75 years. Genetic analysis of peripheral blood leukocytes revealed a point mutation (11778G>A) in MTND 4 encoded by mitochondrial DNA . The most distinctive feature of our patient was the elevation of serum LA and PA levels and the LA / PA ratio by cycle ergometer exercise without clinical or pathological skeletal muscle involvement. Also, droplet digital PCR (dd PCR ) showed that mutation fractions of m.11778G>A in peripheral blood and muscle sample were higher than 99.9%, indicating “homoplasmy”. Although no cases of LHON with clinical impairment of skeletal muscle have been reported, subclinical mitochondrial dysfunction has been reported. We concluded that the ergometer test sensitively detected a subclinical change caused by mitochondrial respiratory chain dysfunction, showing the diversity of genotype and phenotype relationship in LHON .