Screening Of Multiple Sclerosis Associated Genes In The Han Chinese Population And Study Of Association Between Genetic Variations In FCRL3and Multiple Sclerosis

ObjectiveMultiple sclerosis （MS） and neuromyelitis optica （NMO） are common inflammatorydemyelinating diseases of the central nervous system （CNS）. Recently, a number ofMS susceptibility loci were identified by genome-wide association study （GWAS）.We aimed to evaluate the association of these loci with MS and NMO in the HanChinese population.MethodsSeventy-one single nucleotide polymorphisms （SNPs） were selected and genotypedby matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF MS） in154MS patients,109NMO patients and301controls fromsoutheastern China.Results1. Among these71SNPs, only7SNPs were identified to be associated with MS asfollows:rs11129295/EOMES（P=0.008,OR=1.559）,rs2293370/TMEM39A（P=0.018,OR=0.695）,rs703842/CYP27B1（P=0.036,OR=1.354）,rs7522061/FCRL3（P=0.0003,OR=0.593）,rs3761959/FCRL3（P=0.0005,OR=0.601）,rs7528684/FCRL3（P=0.0007,OR=0.616）,rs10466829/CLECL1（P=0.026,OR=0.724）.2. Among these71SNPs, only6SNPs were identified to be associated with NMO asfollows:rs1800693/TNFRSF1A（P=0.032,OR=1.574）,rs7522061/FCRL3（P=0.009,OR=0.658）,rs3761959/FCRL3（P=0.014,OR=0.678）,rs7528684/FCRL3（P=0.026,OR=0.701）,rs6937876/ATG5（P=0.023,OR=1.449）,rs763361/CD226（P=0.036,OR=1.404）.Conclusions1. Most of MS susceptibility loci from GWAS in Caucasians are not associated withHan Chinese MS. 2. The greatest individual impact is from FCRL3gene on MS susceptibility in theHan Chinese.3. The variants of FCRL3are associated with MS and NMO in the Han Chinese. ObjectiveIn the first part of study, we found that variants of Fc receptor-like3（FCRL3） areassociated with multiple sclerosis （MS） and neuromyelitis optica （NMO） in the HanChinese. The aim of this part of study is to test association of FCRL3variants withphenotype of MS and NMO in the Han Chinese, especially with the presence ofoligoclonal bands （OCB） and AQP4antibody （AQP4-ab） and to explore the role ofFCRL3in the pathogenesis of MS.MethodsOCB were analyzed by isoelectric focusing and AQP4-ab was detected as with animmunofluorescence assay using HEK293cells transfected with recombinant humanAQP4gene. FCRL3mRNA levels of peripheral blood morphonuclear cells （PBMC）collected from34MS cases in the relapse and41controls were measured by real-timequantitative RT-PCR.Results1. The rs7528684was in high linkage disequilibrium （LD） with rs752206andrs3761959, while the rs11264799, another promoter SNP, showed relatively low LDwith the above three SNPs （mean R2=0.41）.2. The rs7528684was a protective factor for MS in the dominant model （CT+CC vsTT, P=0.002, OR=0.528） but not for NMO, while the rs11264799was a protectivefactor for NMO in the dominant model （AG+AA vs GG, P=0.005, OR=0.492） but notfor MS.3. We found that the TG haplotype （rs7528684and rs11264799） was a risk factor forMS （p=0.003, OR=1.534） and the haplotype CG was a protective factor for MS（p=0.012, OR=0.613）. In NMO group, the haplotype TG was a risk factor （p=0.012, OR=1.509）, while the haplotype CA was a protective factor （p=0.015, OR=0.617）.4. In this cohort, no association was found between two SNPs rs7528684andrs11264799and age at onset （AAO） and Expanded Disability Status Scale （EDSS） inMS patients and there was no significant association between the two SNPs and AAOin NMO patients.5. After stratification for OCB status, the allele C of rs7528684was significantlylower in OCB-positive MS than-negative MS, and was negatively associated withOCB positivity (p=1.488×10^-4, OR=0.354). However, there was no significantdifference in the genotype distribution of rs11264799between AQP4-ab positiveand-negative NMO （p=0.383） and the allel A of rs11264799was not associated withAQP4-ab positivity （p=0.214）.6. PBMC from controls CC homozygotes expressd higher levels of FCRL3mRNAthan TT homozygotes and CT heterozygotes （CC vs TT: P=0.021, CC vs CT:P=0.025）. The genotype effect on FCRL3mRNA levels was also significiant in MScases （CC vs TT: P=0.013, CC vs CT: P=0.045）. Moreover, threre was significantdifference in expression of FCRL3between MS and controls with the same genotype(CC: p=2.481×10^-4; CT: p=1.982×10^-5; TT: p=0.029).Conclusions1.The variants of FCRL3are associated with MS and NMO, and the allel C ofrs7528684is negtive associated with the presence of OCB in Han Chinese MSpatients.2. SNP rs7528684influences expression of FCRL3mRNA from PBMC. PBMC fromMS patients in the relapse phase express higher levels of FCRL3mRNA than controls,which suggests a protective response.