Variants of Interferon Regulatory Factor 5 are Associated with Neither Neuromyelitis Optica Nor Multiple Sclerosis in the Southeastern Han Chinese Population

Interferon Regulatory Factor 5 Gene Polymorphisms and mRNA Expression Levels Are Associated with Neuromyelitis Optica Spectrum Disorder

Interferon regulatory factor 5 (IRF5) is a critical transcription factor in the toll-like receptor signaling pathway. It is associated with autoimmune disorders, such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. However, the relationship between the functional single nucleotide polymorphisms (SNPs) of IRF5 and its mRNA expression level in patients with neuromyelitis optica spectrum disorder remains unclear. The present study aimed to investigate the relationship between polymorphisms and mRNA expression levels of the IRF5 gene with the incidence of neuromyelitis optica spectrum disorder (NMOSD) in northern Chinese Han people. Two loci of the IRF5 gene (rs2004640 and rs2280714) of 164 patients with NMOSD and 269 healthy subjects were genotyped using the multiple SNaPshot technique. The frequencies of alleles, genotypes, and haplotypes were compared. Stratified analysis was performed according to age, sex, AQP4 status, onset age, and Expanded Disability Status Scale (EDSS) score. The IRF5 mRNA levels in peripheral blood mononuclear cells (PBMCs) of 64 NMOSD patients (32 patients in the acute stage and 32 patients in the remission stage) and 35 healthy subjects were detected by real-time PCR. The association of SNP polymorphisms with the mRNA expression level was determined by nonparametric tests. Allele and genotype frequency distributions of rs2004640 showed significant differences between both groups. Compared to healthy controls, the frequency of rs2004640 T allele markedly increased in patients (OR = 1.51, 95% CI = 1.09-2.08, P = 0.005). Minor allele T and GT genotype of rs2004640 that significantly increases the risk of NMOSD were discovered using genetic inheritance models (codominant, dominant, and overdominant) and haplotype analyses. Subsequent haplotype analyses revealed that the major haplotype "T-A" containing the risk alleles (the SNP sequence of the alleles was rs2004640 and rs2280714) had adverse effects on NMOSD. Based on the stratification analysis according to the EDSS score, the GT genotype frequency in the EDSS ≥ 4 group (38.2%) was markedly lower than that in the EDSS < 4 group (61.8%) (OR = 0.32, 95% CI = 0.15-0.68, P = 0.0054), with a significant difference. The IRF5 mRNA expression level was increased in NMOSD patients compared to that in normal subjects. IRF5 gene polymorphisms may be tightly associated with the genesis and progression of NMOSD in northern Chinese Han people. IRF5 mRNA expression was increased in patients with NMOSD and significantly increased in patients with acute phase. Perhaps IRF5 expression levels can be used as a predictor of disease activity in the future.

A Comprehensive Review on the Role of Genetic Factors in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorders (NMOSD) comprise a variety of disorders being described by optic neuritis and myelitis. This disorder is mostly observed in sporadic form, yet 3% of cases are familial NMO. Different series of familial NMO cases have been reported up to now, with some of them being associated with certain HLA haplotypes. Assessment of HLA allele and haplotypes has also revealed association between some alleles within HLA-DRB1 or other loci and sporadic NMO. More recently, genome-wide SNP arrays have shown some susceptibility loci for NMO. In the current manuscript, we review available information about the role of genetic factors in NMO.

Variant of EOMES Associated with Increasing Risk in Chinese Patients with Relapsing-remitting Multiple Sclerosis

Background:

Multiple sclerosis (MS) is a common central nervous system autoimmune disorder. Increasing number of genome-wide association study (GWAS) analyses hint that MS is strongly associated with genetics. Unfortunately, almost all the GWAS analyses were Caucasian population based. Numbers of risk loci might not be replicated in Chinese MS patients. Hence, we performed a MassArray Assay to genotype the previously reported variants located in the transcription regulation genes in order to elucidate their role in the Chinese MS patients.

Methods:

One hundred and forty-two relapsing-remitting MS (RRMS) patients and 301 healthy controls were consecutively collected from September 2, 2008, to June 7, 2013, as stage 1 subjects. Eight reported transcription regulation-related single-nucleotide polymorphisms (SNPs) were genotyped using the Sequenom MassArray system. In stage 2, another 44 RRMS patients and 200 healthy controls were consecutively collected and Sanger sequenced from April 7, 2015, to June 29, 2017, for the validation of positive results in stage 1. Differences in allele and genotype frequencies between patients and healthy controls, odds ratios, and 95% confidence intervals were calculated with the Chi-square test or Fisher's exact test. Hardy-Weinberg equilibrium was tested also using the Chi-square test.

Results:

In stage 1 analysis, we confirmed only one previously reported risk variant, rs11129295 in EOMES gene. We found that the frequency of T/T genotype was much higher in MS group (χ² = 10.251, P = 0.005) and the T allele of rs11129295 increased the risk of MS (χ² = 10.022, P = 0.002). In stage 2 and combined analyses, the T allele of rs11129295 still increased the risk of MS (χ² = 4.586, P = 0.030 and χ² = 16.378, P = 5.19 × 10⁻⁵, respectively).

Conclusions:

This study enhances the knowledge that the variant of EOMES is associated with increasing risk in Chinese RRMS patients and provides a potential therapeutic target in RRMS.