Association of IL1B Gene Polymorphisms (rs1143634 and rs16944) with Schizophrenia in Iranian Patients

Schizophrenia (SCZ) is a deleterious neuropsychological disorder with a worldwide incidence of 1% and unknown etiology. Understanding the role of genetic variants in disease development would enable us to explain the disorder's molecular mechanism and find a more effective prognostic approach. Several studies in various European and East Asian populations have displayed the association of schizophrenia with functional polymorphisms such as rs16944 and rs1143634 that lie within inflammatory pathway genes. This study aimed to evaluate the association of Interleukin-1 beta (IL1B) variants (rs16944, rs1143634) with schizophrenia in the Iranian population for the first time. 565 individuals (240 cases and 325 controls) were recruited. Genotyping was conducted for IL1B single nucleotide polymorphisms (SNPs) (rs16944 and rs1143634) using polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP). In addition, the haplotype analysis was conducted. All statistical analysis was performed using SPSS version 26. Regarding rs1143634 (C > T), T carrier genotypes (CT, TT) compared to CC homozygous genotypes showed a significantly more protective effect (p-value < 0.001). Similarly, concerning the co-dominant model, CT heterozygous genotypes in comparison with homozygous genotypes (CC, TT) illustrated a protective impact regarding schizophrenia (p-value < 0.001). Findings showed a significant difference between cases and healthy controls regarding the rs1143634 (C > T) allele frequency (p-value = 0.025), whereas it determined no considerable difference given rs16944 (p-value = 0.41). Furthermore, in the case of rs16944 (T > C), we found no significant association between case and control groups (p-value = 0.69). Haplotype analysis demonstrated that the C-C (rs1143634-rs16944) haplotype was significantly associated with the risk of schizophrenia (p-value = 0.013). The findings suggest that IL1B rs1143634 (C > T) is significantly associated with SCZ in the Iranian population.