Genetic susceptibility to multiple sclerosis may be linked to polymorphism of the myelin basic protein gene.

The present paper compares the genetic polymorphism of a part of the myelin basic protein (MBP) gene in 64 Danish MS patients with that of 57 normal controls. PCR analysis, using primers flanking the 5' area from 479 to 1812 bp upstream the initiator methionine in the MBP gene, revealed that genetic susceptibility to MS is linked to polymorphism in the part of the MBP gene studied. Thus we found three different band patterns i.e. a homozygote with a 1445 bp long fragment, a homozygote with a fragment 1318 bp long and a heterozygote with both bands present. 59% of 64 patients with MS were homozygous for 1.445 kb allele, versus 40% of 57 control subjects, 18% of the control subjects were homozygous for the 1.318 kb, while only 0.7% of the MS patients possessed this allele. The differences between incidence of the three band pattern in the MS and the control group were significant at 1% level. Validation analysis furthermore support, the view that the 1445 bp PCR fragment is associated with MS.