Genetic analysis of rs11038167, rs11038172 and rs835784 polymorphisms of the TSPAN18 gene in Iranian schizophrenia patients

Background: Schizophrenia is a debilitating psychiatric disorder. In a recent GWA study, three single nucleotide polymorphisms (SNPs) within the intronic region of TSPAN18 gene, rs11038167, rs11038172 and rs835784 were shown to be significantly associated with the risk of schizophrenia. However, the results across the following replication studies are inconsistent. This study aimed to further explore the association of these three variants with schizophrenia in the Iranian population. Methods: Genomic DNA was extracted from the peripheral blood of 496 SZ patients and 501 gender and age-matched healthy controls. Rs11038167, rs11038172 and rs835784 were genotyped using PCR-RFLP method in all subjects. Association of the genotyped SNPs and SZ was tested using chi-squared test and logistic regression models. The difference between genotypes in the two case and control groups was further assessed under log-additive, recessive and dominant genetic models using SNPassoc package of R. Results: We have found significant differences in allele frequencies of the rs11038167 and rs835784 polymorphisms and also in genotype distributions of all three SNPs. The A allele of the rs11038167 and rs835784 polymorphisms in addition to the AA genotype of the three polymorphisms were associated with increased susceptibility to schizophrenia. Conclusion: These results confirm the significant association between rs11038167 and rs835784 and rs11038172 polymorphisms and increased risk of schizophrenia in Iranian population suggested earlier in previous studies on Han Chinese population.