Interleukin 2 receptor α chain gene polymorphisms and risks of multiple sclerosis and neuromyelitis optica in southern Japanese

Background Interleukin 2 receptor α subunit (IL2RA) is a genetic risk for multiple sclerosis (MS) in Caucasians. However, the association between MS and IL2RA in Japanese idiopathic demyelinating diseases of the central nervous system has not been examined. Objective To determine whether IL2RA gene polymorphisms confer risks of developing MS or neuromyelitis optica (NMO) in a Japanese population. Methods DNA samples were obtained from 115 MS patients, 75 NMO/NMO spectrum disorder (NMOSD) patients, and 238 healthy controls. The single nucleotide polymorphisms (SNPs) rs2104286, rs12722489, and rs7090512 were genotyped by real-time PCR using TaqMan SNP genotyping assays. Results No significant associations of the three IL2RA SNPs with the development of the diseases were observed. In MS patients only, the annualized relapse rates were significantly higher for the rs2104286-TT genotype than for the non-TT (CT+CC) genotype and for the rs12722489-CC genotype than for the non-CC genotype in females (p = 0.0138 for both), but not in males. Conclusions Although the possibility that IL2RA is a risk factor for MS development was not confirmed in this Japanese population, IL2RA gene polymorphisms were able to modify the disease activity in female MS patients, but had no influence on either susceptibility or disease phenotype in NMO/NMOSD patients.