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Expanding the molecular and phenotypic spectrum of truncating MT-ATP6 mutations

OBJECTIVE: To describe the clinical and functional consequences of 1 novel and 1 previously reported truncating MT-ATP6 mutation. METHODS: Three unrelated probands with mitochondrial encephalomyopathy harboring truncating MT-ATP6 mutations are reported. Transmitochondrial cybrid cell studies were us...

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Detalles Bibliográficos
Autores principales: Bugiardini, Enrico, Bottani, Emanuela, Marchet, Silvia, Poole, Olivia V., Beninca, Cristiane, Horga, Alejandro, Woodward, Cathy, Lam, Amanda, Hargreaves, Iain, Chalasani, Annapurna, Valerio, Alessandra, Lamantea, Eleonora, Venner, Kerrie, Holton, Janice L., Zeviani, Massimo, Houlden, Henry, Quinlivan, Rosaline, Lamperti, Costanza, Hanna, Michael G., Pitceathly, Robert D.S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Wolters Kluwer 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6984135/
https://www.ncbi.nlm.nih.gov/pubmed/32042910
http://dx.doi.org/10.1212/NXG.0000000000000381
Descripción
Sumario:OBJECTIVE: To describe the clinical and functional consequences of 1 novel and 1 previously reported truncating MT-ATP6 mutation. METHODS: Three unrelated probands with mitochondrial encephalomyopathy harboring truncating MT-ATP6 mutations are reported. Transmitochondrial cybrid cell studies were used to confirm pathogenicity of 1 novel variant, and the effects of all 3 mutations on ATPase 6 and complex V structure and function were investigated. RESULTS: Patient 1 presented with adult-onset cerebellar ataxia, chronic kidney disease, and diabetes, whereas patient 2 had myoclonic epilepsy and cerebellar ataxia; both harbored the novel m.8782G>A; p.(Gly86*) mutation. Patient 3 exhibited cognitive decline, with posterior white matter abnormalities on brain MRI, and severely impaired renal function requiring transplantation. The m.8618dup; p.(Thr33Hisfs*32) mutation, previously associated with neurogenic muscle weakness, ataxia, and retinitis pigmentosa, was identified. All 3 probands demonstrated a broad range of heteroplasmy across different tissue types. Blue-native gel electrophoresis of cultured fibroblasts and skeletal muscle tissue confirmed multiple bands, suggestive of impaired complex V assembly. Microscale oxygraphy showed reduced basal respiration and adenosine triphosphate synthesis, while reactive oxygen species generation was increased. Transmitochondrial cybrid cell lines studies confirmed the deleterious effects of the novel m.8782 G>A; p.(Gly86*) mutation. CONCLUSIONS: We expand the clinical and molecular spectrum of MT-ATP6-related mitochondrial disorders to include leukodystrophy, renal disease, and myoclonic epilepsy with cerebellar ataxia. Truncating MT-ATP6 mutations may exhibit highly variable mutant levels across different tissue types, an important consideration during genetic counseling.