Immune System Genes Linked to Multiple Sclerosis
Variant alleles confer a small increased risk of disease
FRIDAY, Aug. 31 (HealthDay News) -- Researchers have identified variants in several genes involved in immune system regulation that are associated with an increased risk of multiple sclerosis, according to a study published in the Aug. 30 issue of the New England Journal of Medicine.
As part of the International Multiple Sclerosis Genetics Consortium, David A. Hafler, M.D., of Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues conducted a genomewide association study involving over 12,000 subjects to identify alleles associated with an increased risk for multiple sclerosis.
Researchers identified two single-nucleotide polymorphisms (SNPs) within the interleukin-2 receptor α gene (IL2RA) and one SNP within the interleukin-7 receptor α gene (IL7RA) that were associated with multiple sclerosis, though the increase in risk attributable to each variant allele was small. In addition, multiple SNPs within the HLA-DRA locus were found to have a strong association with multiple sclerosis.
An associated editorial comments, "It is important to recognize that the increased risk contributed by IL2RA and IL7RA is very low and that these two alleles explain only a very small proportion of the variance (0.2 percent) in the risk of multiple sclerosis." Rather, "the HLA region retains its unique position as the only known major risk gene for multiple sclerosis."