Mitochondrial and nuclear genes as the cause of complex I deficiency.

Multiple sclerosis (MS) is an immunological inflammatory disease of the central nervous system. The pathogenesis of MS is incompletely understood, but various studies have suggested that mitochondrial dysfunction is associated with the disease. Mitochondria are among the main cellular sources of reactive oxygen and nitrogen species, and they play a pivotal role in many neuro-pathological conditions. The mitochondrial nuclear subunit of complex I gene in mitochondria may play a role in MS, and understanding this role may provide rationale for novel approaches to treatment of the disease and the development of novel therapies. We designed a molecular study to demonstrate biochemical defects in complex I activity and found some novel nucleotide substitutions in mitochondrial DNA that might be involved in the pathogenesis of MS. The mitochondrial complex subunit I sequence was amplified and sequenced in MS patients. Although no reported pathogenic mutations were found in these patients, other studies have clearly indicated that the mitochondrial nuclear complex subunit I gene plays a significant role in MS pathogenesis.