Association of IL2RA polymorphisms with susceptibility to multiple sclerosis is not explained by missense mutations in IL2RA

Genome-wide association studies have identified an association between two intronic single nucleotide polymorphisms (SNPs), rs12722489 and rs2104286, in the interleukin-2 receptor alpha-chain gene (IL2RA) and susceptibility to multiple sclerosis (MS). We studied these SNPs in association with susceptibility to and severity of MS in a population-based cohort of 220 patients from Olmsted County, Minnesota, compared with 442 matched controls. We sequenced the exons, splice sites and 5' and 3' untranslated regions in 27 randomly selected MS patients (powered for allele frequency >= 0.04) to search for mutations. No novel missense mutation was identified. Two patients (7.5%) had an exon 2 SNP (rs4308625) and two patients had an exon 4 SNP (rs2228149), both synonymous.