A Study of the Association between SNP8NRG241930 in the 5' End of Neuroglin 1 Gene with Schizophrenia in a Group of Iranian Patients

OBJECTIVE Neuregulin1 (NRG1) gene is among the most promising candidate genes for schizophrenia. This gene is located on 8p22-p12, a region with a reported linkage to schizophrenia. Several studies have reported an association between schizophrenia and the 5' end polymorphisms in this gene. However, some studies have failed to confirm the role of NRG1 gene in the pathogenesis of schizophrenia. In the current study, we attempt to examine the association of SNP8NRG241930 from the NRG1 gene with schizophrenia in an Iranian population. It is noteworthy that there has been no report on the NRG1 association with schizophrenia in a population from the Middle East region. MATERIALS AND METHODS Genomic DNA samples were obtained via isolation from the peripheral blood cells of 95 unrelated subjects with schizophrenia and 95 matched healthy controls from southwest Iran. SNP8NRG241930 was genotyped by PCRRFLP using ScaI as a restriction endonuclease enzyme. Association of the SNP with schizophrenia was examined using the chi-square test. The frequency difference of alleles and genotypes between the two groups were compared. P≤0.05 was considered significant. RESULTS Statistical analysis on the studied polymorphism showed that both case and control groups were in Hardy-Weinberg equilibrium. The frequency of high risk allele (G allele) was 72.6% in patients, while this number was 56.8% in controls. The genotype frequencies in the patient group were as follows: GG (54%), GT (38%) and TT (8%) vs. genotype frequencies in the control group of: GG (26%), GT (63 %) and TT (11%). CONCLUSION Considering allele and genotype frequencies, a significant association was observed between schizophrenia and SNP8NRG241930. The current study adds weight to the idea that some functional polymorphisms could exist in the 5' end of the NRG1 gene which increase susceptibility to schizophrenia. This is the first time that supportive evidence shows an involvement of the NRG1 locus in schizophrenia in an Iranian sample population.