The T-cell immunoglobulin and mucin domains 1 (TIM-1) and 3 (TIM-3) have been shown to be associated with susceptibility to rheumatoid arthritis (RA) in many ethnicities. In this study, we investigated the rs7700944 polymorphism of the intron region of TIM-4 gene in Chinese Han and Hui populations, with and without RA in Ningxia Hui Autonomous Region of China. Our results demonstrated genetic variations of the TIM-4 gene, along with significantly different distributions of genotypes and alleles at rs7700944 site in these two populations, with or without RA (P < 0.01). In addition, a strong association between the polymorphism with RA susceptibility was found in the studies of Chinese Han and Hui ethnic groups (P < 0.01), although the risk genotype contributed to RA susceptibility was different between the Han and Hui groups (P < 0.01). The AG was the risk genotype for RA in Han population, while GG was the risk genotype at rs7700944 site of TIM-4 gene in Hui ethnicity. In addition to the genotype, the risk alleles of this single nucleotide polymorphism for RA in these two populations were also different, individuals with A allele was more susceptible to RA in Chinese Han [odds ratio (OR) = 1.930; 95% CI 1.412, 2.636; P < 0.01], but the risk allele in Hui was G in this study (OR = 1.823; 95% CI 1.330, 2.498; P < 0.01). These findings strongly suggest that polymorphism of rs7700944 of TIM-4 may be a potential genetic variant among distinguished populations, as well as an important genetic factor associated with the RA susceptibility in many ethnicities.
José Lorenzo Santos ValleJose Lorenzo Santos Valle
Santiago Niño BecerraMónica Martínez-Blasco
Diego Patricio Vallejo SánchezKatherine María Chávez AtienciaMaría del Carmen Ibarra Chango
Nora Isabel Santiago ChávezJenny Margoth Gamboa Salinas