MITOCHONDRIAL SEQUENCE VARIANTS IN PATIENTS WITH SCHIZOPHRENIA

To investigate whether mitochondtial mutations underly susceptibility to schizophrenia, we sequenced the mtDNAs of two unrelated Swedish pat ients with schizophrenia and low cytochrome oxidase activity and two m aternally related Scottish patients from a family with suspected mater nal inheritance of the disease. We found five substitutions in coding regions that have not previously been described as polymorphisms. Thes e new substitutions were studied in 81 schizophrenic patients and five control groups from Sweden and Scotland and found to differ in freque ncy between populations, emphasizing the importance of using large and well-defined control materials for evaluating the association of mtDN A mutations with disease. The results do not lend strong support to th e association of a particular mtDNA substitution with increased risk f or schizophrenia. However, the trend towards a higher frequency of sub stitutions in the patients deserves further attention.