Association of Alu Insertion Polymorphism in Progesterone Receptor Gene with Risk of Multiple Sclerosis

Background and purpose: Multiple sclerosis (MS) is a chronic autoimmune disease in which the myelin sheaths of nerve cells in the brain and spinal cord are damaged. The prevalence of disease is higher in women and it seems that sex hormones, which usually exert their effects through receptors, are involved in susceptibility to MS. Considering the functional role of Alu insertion 306 bp polymorphism of progesterone receptor in expression level of progesterone receptor, in this study, the association of Alu insertion polymorphism in intron 7 of progesterone receptor with the risk of MS was investigated. Materials and methods: In a case-control study, genomic DNA was extracted from the blood samples of 200 patients (180 women and 20 men) with relapsing remitting MS (RRMS) and 226 healthy individuals (186 women and 40 men) as a control group. In order to determine the polymorphic genotype of Alu insertion, PCR technique was used and the PCR product was electrophoresed on 2% agarose gel. Data were analyzed in SPSS V21 using logistic regression test. Results: Findings showed that WI (P= 0.003) and II (P= 0.001) genotypes increase the risk of MS compared to WW genotype, and allele I acts as a risk allele (P<0.001). Conclusion: According to this study, it seems that allele I of Alu insertion polymorphism may play a dominant role in susceptibility to MS by decreasing PGR gene expression.