Sammanfattning
Up to 20% of all multiple sclerosis (MS) cases are familial. The concordance rates for monozygotic and dizygotic twins are 25-
30% and 3-5% respectively. Certain isolated regions have a higher prevalence of MS. An estimated 30% of the disease heritability is
accounted for, mostly by common risk alleles. Interpretation of risk alleles, gene-gene and gene-environment interactions is
challenging, but all are believed to be important factors in the development of MS. Isolates and MS families are warranted for further
research concerning these issues.