Association analysis of IL7R polymorphisms with inflammatory demyelinating diseases

Multiple sclerosis (MS) and neuromyelitis optica (NMO), which are referred to as inflammatory demyelinating diseases (IDDs), are autoimmune diseases affecting the central nervous system. Interleukin-7 receptor (IL7R) encodes for a receptor protein that is important in the development of immune cells. Several studies have reported significant associations between IL7R polymorphisms and MS. The aim of the present study was to investigate a possible association between IL7R polymorphisms and IDDs such as MS and NMO. Thirteen single nucleotide polymorphisms (SNPs) were selected based on their linkage disequilibrium (LD), minor allele frequency (MAF) and location, and were genotyped in 178 IDD patients and 237 healthy controls. The association of SNPs with IDD risk was analyzed by logistic regression. A meta-analysis on the association between rs6897932 and the risk of MS was also performed. Statistical analyses revealed that a common SNP, rs6897932, was marginally associated with IDD in a recessive model (P=0.003, P-cor.=0.03), which had shown significant associations with MS in previous studies. The results replicated the significant association found between rs6897932 and IDD. In addition, the meta-analysis of rs6897932 clearly demonstrates a higher magnitude of risk in Asian populations than in Caucasian populations. Although there are certain limitations to our study, the results indicate that the genetic variation of IL7R may be associated with IDDs such as MS and NMO in the population studied.