The Association Between The PADI4 Gene Polymorphisms And The Susceptibility And TCM Syndromes Of Rheumatoid Arthritis In Chinese Han Population

Objective:To evaluate the susceptibility of rheumatoid arthritis (RA), we analyzed the allele frequencies of PADI4 gene at the so-called PADI4₉2 single nucleotide polymorphisms (SNP) site among a group of patients with RA in Chinese Han population and a control group of people from the healthy blood donors (HBDs).Methods:Blood samples were obtained from 302 RA patients and 322 HBDs in Chongqing. Genomic DNA samples were purified from the whole peripheral blood of subjects. Gene frequency was identified by means of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The qualitative data was analyzed by x2 test, while the qualitative data was analyzed by one-way ANOVA and t test.Results:Two alleles, a wild type C and a variant allele G were identified in the PADI4₉2. The genotype frequencies of C/C, C/G and G/G were 0.332,0.488,0.180 in the HBDs and 0.295,0.474,0.232 in the RA patients, respectively. Distribution of the PADI4₉2 alleles among the RA patients and HBDs was in consistent with Hardy-Weinberg equilibrium. No statistical difference in PADI4₉2 alleles was found between male and female individuals (x2 0.889, P= 0.641), and age of the population (C/C 39.4±16.2 years, C/G 39.4±15.0 years, G/G 39.9±15.7 years, P= 0.953).There was no association between RA and the PADI4₉2 polymorphisms in Chongqing Chinese Han population (OR 1.198,95%CI 0.958-1.498, P= 0.113). No association was found when patients were classified according to the RF, anti-CCP and AKA positivity. No difference was found between the PADI4₉2 polymorphisms and the parameters that reflected the disease activity of RA, such as ESR, swell joint count, tenderness joint count and DAS28. No difference was also found between the PADI4₉2 polymorphisms and the onset age of RA. There was a statistical difference (P= 0.030) in the course of RA patients between C/G (5.8±6.7 years) and G/G (8.8±9.5 years), but not with G mutant allele (P= 0.878). The significant difference was also found in the level of direct bilirubin (C/C 3.7±1.9μmol/L, C/G+G/G 3.2±1.3μmol/L, P= 0.012) and the count of white blood cell (C/C 5.9±2.5×109/L, C/G+G/G 6.7±2.5×109/L, P= 0.017).The genotype frequencies of C/C, G/C and G/G were 0.241,0.434,0.325 in the ShiReZuLuo type,0.405,0.432,0.162 in the HanShiZuLuo type and 0.311,0.556,0.133 in the GanShenKuiXu type of RA patients, respectively. There was a statistical difference between PADI4₉2 polymorphisms and the Traditional Chinese Medical (TCM) syndromes of RA patients (P= 0.024). There was a significant association between C/C wild homozygote and the greasy tongue fur (P= 0.012). No association was found in the body of the tongue, lingual contour, coating color and pulse condition.Conclusion:1.The distribution of the PADI4₉2 allele frequencies in Chonqing Chinese Han population is in consistent with Hardy-Weinberg equilibrium.2. The PADI4₉2 polymorphisms are no association with the genetic susceptibility to RA in Chonqing Chinese Han population.3. There is a statistical difference in the course of RA patients between C/G and G/G, but not with G mutant allele. The significant difference is also found in the level of direct bilirubin and the count of white blood cell. But the reason of the difference is unclear.4. No Statistical difference between the PADI4₉2 polymorphisms and the positivity of RF, anti-CCP and AKA is found in RA patients. No difference is found between the PADI4₉2 polymorphisms and the parameters that reflected the disease activity of RA, such as ESR, swell joint count, tenderness joint count and DAS28.5. The PADI4₉2 polymorphisms are associated with the Traditional Chinese Medical (TCM) syndromes of RA patients.