Leigh DiseaseCytochrome-c Oxidase DeficiencySyndromeElectron Transport Complex IBrain Diseases, MetabolicMitochondrial EncephalomyopathiesMitochondrial ProteinsMitochondrial DiseasesNADH DehydrogenaseMitochondrial Proton-Translocating ATPasesElectron Transport Complex IVDNA, MitochondrialMELAS SyndromeMutationEncephalomalaciaOxidative PhosphorylationMitochondriaFounder EffectMembrane ProteinsDNA Mutational AnalysisPedigreeFibroblastsBrainDown SyndromeMetabolic Syndrome XProteinsInfant, NewbornMagnetic Resonance ImagingMolecular Sequence Data