Ethnic variation in the mitochondrial targeting sequence polymorphism of MnSOD

In contrast to CuZn superoxide dismutase (SOD), only a very limited number of mutations have been described in MnSOD. One interesting example is a polymorphism (Ala-9Val) in the mitochondrial targeting sequence of this radical-scavenging enzyme. We have studied the Ala-9Val polymorphism in various ethnic groups by means of the oligonucleotide ligation assay. There were significant variations in this unique polymorphism between three different language groups: Baltic (Lithuanians), Finnic (Finns and Saamis) and Germanic (Swedes). The Ala frequency in an Asiatic population (Chinese) was significantly lower than in most European populations. This polymorphism may affect the mitochondrial targeting rate of MnSOD which may result in mitochondrial damage with implication in various late-onset neurological diseases.