Background: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system, characterised by demyelinisation, gliosis and various degrees of axonal damage. The cause of the disease is unknown though there is evidence that MS is an immune mediated disease in which genetic, environmental and stochastic factors are involved.
Material and methods: Evidence of genetic influence in MS is reviewed.
Results: About 20% of patients have other family members with MS. First-degree relatives of MS patients have increased risk (2-5%) of developing MS compared to the risk in the general population (0.1%). The concordance rate in monozygotic twins (25-30%) is higher than in dizygotic twins (2-5%). Genetic analysis has shown association and linkage of MS to the HLA-DR2, DQ6 haplotype. Genome-wide screens have shown chromosome regions of potential importance.
Conclusion: MS is a complex disease in which several genes are involved. Despite extensive candidate gene studies and genome-wide linkage screens, the HLA-DR2, DQ6 haplotype is the only genetic region that has shown unequivocal association and linkage to the disease. Further studies aimed at defining other MS susceptibility and disease-modifying genes are in progress.