title: The role of mtDNA background in disease expression: a new primary LHON mutation associated with Western Eurasian haplogroup J.
abstract: Leber's hereditary optic neuropathy (LHON) is a maternally transmitted form of blindness caused by mitochondrial DNA (mtDNA) mutations. Approximately 90% of LHON cases are caused by 3460A, 11778A, or 14484C mtDNA mutations. These are designated "primary" mutations because they impart a high risk for LHON expression. Although the 11778A and 14484C mutations unequivocally predispose carriers to LHON, they are preferentially associated with mtDNA haplogroup J, one of nine Western Eurasian mtDNA lineages, suggesting a synergistic and deleterious interaction between these LHON mutations and haplogroup J polymorphism(s). We report here the characterization of a new primary LHON mutation in the mtDNA ND4L gene at nucleotide pair 10663. The homoplasmic 10663C mutation has been found in three independent LHON patients who lack a known primary mutation and all of which belong to haplogroup J. This mutation has not been found in a large number of haplotype-matched or non-haplogroup-J control mtDNAs. Phylogenetic analysis with primarily complete mtDNA sequence data demonstrates that the 10663C mutation has arisen at least three independent times in haplogroup J, indicating that it is not a rare lineage-specific polymorphism. Analysis of complex I function in patient lymphoblasts and transmitochondrial cybrids has revealed a partial complex I defect similar in magnitude to the 14484C mutation. Thus, the 10663C mutation appears to be a new primary LHON mutation that is pathogenic when co-occurring with haplogroup J. These results strongly support a role for haplogroup J in the expression of certain LHON mutations.
authors.affiliation: Center for Molecular Medicine, Emory University School of Medicine, 420B Dental Building, 1462 Clifton Road NE, Atlanta, GA 30322, USA. mdbrown@gen.emory.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Brown
authors.forename: Elena
authors.initials: E
authors.lastname: Starikovskaya
authors.forename: Olga
authors.initials: O
authors.lastname: Derbeneva
authors.forename: Seyed
authors.initials: S
authors.lastname: Hosseini
authors.forename: Jon C
authors.initials: JC
authors.lastname: Allen
authors.forename: Irina E
authors.initials: IE
authors.lastname: Mikhailovskaya
authors.forename: Rem I
authors.initials: RI
authors.lastname: Sukernik
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Wallace
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001208:Asia / Q000208:ethnology; D002460:Cell Line; D004272:DNA, Mitochondrial / Q000235:genetics*; D042967:Electron Transport Complex I; D005060:Europe; D005260:Female; D006239:Haplotypes; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics; D029242:Optic Atrophy, Hereditary, Leber / Q000235:genetics*; D010101:Oxygen Consumption / Q000235:genetics; D010375:Pedigree; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide
chemical_list: D004272:DNA, Mitochondrial; C098483:NADH dehydrogenase subunit 4; D009247:NADH, NADPH Oxidoreductases; D009245:NADH Dehydrogenase; D042967:Electron Transport Complex I