Association between HRH4 polymorphisms and ankylosing spondylitis susceptibility.

Target: The purpose of the study was to investigate the association between the histamine H4 receptor (HRH4) polymorphisms and the susceptibility to ankylosing spondylitis (AS).

Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to analyze the HRH4 rs8088140 and rs657132 polymorphisms. Linkage disequilibrium and haplotype analyses were conducted with Haploview software. The genotypes distributions of HRH4 polymorphisms in the control group were tested by Hardy-Weinberg equilibrium (HWE), allele, genotype and haplotype frequencies between the cases and control groups were compared by χ(2) test. The controls were matched with cases by age and gender. The relative risk of AS with HRH4 polymorphisms was represented by odds ratio (OR) with 95% confidence interval (CI) calculated by χ(2) test.

Results: The genotypes distributions of HRH4 rs8088140, rs657132 polymorphisms in controls conformed to HWE. The frequency of rs657132 AA genotype in the case group was obviously higher than that in the control group (P=0.040), and so was the A allele (OR=2.572, 95% CI=1.475-4.486, P=0.022). The frequency differences of A-A haplotype between two groups had statistical significance (P=0.011, OR=2.071, 95% CI=1.172-3.660) through haplotype analysis, indicating A-A might be the susceptible haplotype to AS.

Conclusion: The AA genotypes of HRH4 rs657132 polymorphism may be the susceptible factors for AS, and rs657132 plays a role in generation of AS. In addition, A-A haplotype in rs8088140-rs657132 is also increased the risk of AS.