A novel ND3 mitochondrial DNA mutation in three Korean children with basal ganglia lesions and complex I deficiency

Mitochondrial disorders have notoriously variable clinical presentations, particularly in children. A growing number of reports describe mutations in the mitochondrial DNA (mtDNA)encoded subunits of complex I (EC 1.6.5.3) causing early-onset encephalopathy. Here, we describe two Korean siblings with childhood-onset progressive generalized dystonia and one Korean child with strokelike episodes in infancy; all three had bilateral lesions of the basal ganglia and partial deficiencies of complex 1. Analysis of their mtDNA revealed a novel heteroplasmic m.10197G > A mutation (A47T) in the ND3 (NADH dehydrogenase subunit 3) gene. This study underscores the importance of screening mtDNA-encoded respiratory chain structural genes, including ND3, in pediatric patients with unexplained encephalopathies.