1. Impaired complex I repair causes recessive Leber's hereditary optic neuropathy
- Author
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Stenton, Sarah L., Sheremet, Natalia L., Catarino, Claudia B., Andreeva, Natalia A., Assouline, Zahra, Barboni, Piero, Bare, Ortal, Berutti, Riccardo, Bychkov, Igor, and Caporali, Leonardo
- Subjects
Optic atrophy -- Genetic aspects -- Causes of ,NADH dehydrogenase -- Physiological aspects -- Health aspects ,Health care industry - Abstract
Leber's hereditary optic neuropathy (LHON) is the most frequent mitochondrial disease and was the first to be genetically defined by a point mutation in mitochondrial DNA (mtDNA). A molecular diagnosis is achieved in up to 95% of cases, the vast majority of which are accounted for by 3 mutations within mitochondrial complex I subunit-encoding genes in the mtDNA (mtLHON). Here, we resolve the enigma of LHON in the absence of pathogenic mtDNA mutations. We describe biallelic mutations in a nuclear encoded gene, DNAJC30, in 33 unsolved patients from 29 families and establish an autosomal recessive mode of inheritance for LHON (arLHON), which to date has been a prime example of a maternally inherited disorder. Remarkably, all hallmarks of mtLHON were recapitulated, including incomplete penetrance, male predominance, and significant idebenone responsivity. Moreover, by tracking protein turnover in patient-derived cell lines and a DNAJC30-knockout cellular model, we measured reduced turnover of specific complex I N-module subunits and a resultant impairment of complex I function. These results demonstrate that DNAJC30 is a chaperone protein needed for the efficient exchange of complex I subunits exposed to reactive oxygen species and integral to a mitochondrial complex I repair mechanism, thereby providing the first example to our knowledge of a disease resulting from impaired exchange of assembled respiratory chain subunits., Introduction Leber's hereditary optic neuropathy (LHON, OMIM:535000) was first noted by Von Graefe in 1858 (1) and was formally described as a clinical entity bearing his name by Leber in [...]
- Published
- 2021
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