Polymorphisms and multiple sclerosis in Orkney.

Study of the blood group, isoenzyme, and serum protein systems representing polymorphic variants at 23 loci, in a population of 53 multiple sclerosis patients in Orkney, their relatives, and control series, showed that patients were neither morre homozygous nor more inbred than controls. Any possible association of the disorder with the ABO and rhesus blood groups was not directly causal, but was related to the families of the patients rather than to the patients themselves.