Exploring the Potential Link between Vitamin D Receptor Cdx2 Gene Polymorphisms and Rheumatoid Arthritis in Female Patients: A Study in Erbil, Iraq

Abstract

Background: In the last decades, vitamin D has been a subject of research in several autoimmune diseases, including Rheumatoid Arthritis (RA), a chronic inflammatory disease characterized by a distinctive pattern of joint involvement and joint destruction. Aim: The main goal of the study is to examine the relationship between (RA) and the polymorphism in the vitamin D receptor's Cdx2 gene in a sample of women. Methods: Eighty females (60 with RA and 20 controls) participated in this case-control investigation. The Cdx2 single nucleotide polymorphisms (SNP) of the VDR gene were genotyped using tetra-primer amplification refractory mutation system-polymerase chain reaction technique (ARMS-PCR). Results: The current study discovered that 51 RA patients have the heterozygous GA genotype of the Cdx2 polymorphism despite non-significant values. Although the present findings showed no significant association between Cdx2 gene polymorphisms and the risk of RA, this genotype still represents the majority among the study's RA patients. Moreover, the results showed that the serum VD3 was significantly lower in RA with the GA genotype compared to healthy controls with a similar genotype (p=0.0002). Also RA patients with heterozygote GA genotype for Cdx2 had a relatively lower mean for serum vitamin D3 level than those with homozygote GG genotype. Conclusion: The novelty of this study is to discover the probable association of Vitamin D receptor, caudal-related homeobox 2 (VDR-Cdx2) polymorphism with RA in the given study group for the first time in our society using a tetra primer ARMS-PCR. Additionally, the tetra-primer ARMS-PCR technique was simple, reliable, low-cost, and might be a valuable substitute for Restriction fragment of length polymorphism- polymerase chain reaction– (RFLP-PCR) in routine clinical settings for single nucleotide polymorphism (SNP) genotyping.