Resumen: BACKGROUND: Leigh syndrome (LS) is a serious genetic disease that can be caused by mutations in dozens of different genes. METHODS: Clinical study of a deafness pedigree in which some members developed LS. Cellular, biochemical and molecular genetic analyses of patients'' tissues and cybrid cell lines were performed. RESULTS: mitochondrial DNA (mtDNA) m.1555A>G/MT-RNR1 and m.9541T>C/MT-CO3 mutations were found. The first one is a well-known pathologic mutation. However, the second one does not appear to contribute to the high hearing loss penetrance and LS phenotype observed in this family. CONCLUSION: The m.1555A>G pathological mutation, accompanied with an unknown nuclear DNA (nDNA) factor, could be the cause of the phenotypic manifestations in this pedigree. Idioma: Inglés DOI: 10.3390/genes11091007 Año: 2020 Publicado en: Genes 11, 9 (2020), 11091007 [9 pp] ISSN: 2073-4425 Factor impacto JCR: 4.096 (2020) Categ. JCR: GENETICS & HEREDITY rank: 65 / 175 = 0.371 (2020) - Q2 - T2 Factor impacto SCIMAGO: 1.337 - Genetics (clinical) (Q2) - Genetics (Q2)