Association between polymorphisms of FCRL3, a non-HLA gene, and Behçet’s disease in a Chinese population with ophthalmic manifestations

PURPOSE Studies have shown a strong association of human leukocyte antigens-B51 (HLA-B51) with Behçet's disease (BD). However, little is known about the association of non-HLA genes with BD. The polymorphisms of the Fc receptor-like 3 gene (FCRL3), -169C/T, -110A/G, +358C/G, and +1381A/G, have been reported to be associated with several autoimmune diseases. This study was designed to determine whether the polymorphisms of FCRL3 were associated with susceptibility to BD in a Chinese population mainly with ocular involvement. METHODS A case-control study was performed in 245 Chinese BD patients and 289 controls. Four single nucleotide polymorphisms (SNPs; -169C/T, -110A/G, +358C/G, and +1381A/G) in FCRL3 were detected using polymerase chain reaction restriction fragment length polymorphisms (PCR-RFLP). HLA-B51 genotyping was performed by the PCR sequence specific primers method as described previously. RESULTS The results showed a significantly higher frequency of the G allele at the -110 site in BD patients compared with that in controls (corrected p=0.044, 75.3% versus 67.5%, chi2=7.72). Haplotype CGCG frequency was significantly higher in patients than in controls (corrected p=0.0096) whereas haplotype TACG frequency was significantly lower in patients compared with controls (corrected p=0.032). There was no relationship between clinical signs and FCRL3 polymorphisms. No significant difference was observed between patients and controls after HLA-B51 stratification concerning the four SNPs. CONCLUSIONS Our study suggests that the -110 G allele and the haplotype CGCG of FCRL3 are positively associated with BD in a Chinese population and that the haplotype ATCG might be a protective haplotype for BD.