Abstract
The Neuregulin 1 (NRG1) gene has been associated with schizophrenia in several populations, and all four types of NRG1 genes are linked with neurotransmitters activities. In this study for the first time we have demonstrated an association between NRG1 mutation and schizophrenia in Pakistani population. We examined the relationship of three genetic variants SNPs: rs3924999, rs2954041 and rs35753505 of NRG1 gene with the onset of disease. Genomic DNA samples were obtained from the blood of 100 patients and 80 matched controls. All three NRG1 SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism method and further confirmed by DNA sequencing. The SNPs frequencies were estimated by Hardy-Weinberg equilibrium and Chi-square tests. Our study established a significant association of rs35753505 with schizophrenia but no association with rs3924999 and rs2954041. The frequency of risk allele C was significantly higher (62.5%) in rs35753505 patients when compared to controls (28.13%). Genotype frequency by Hardy-Weinberg equilibrium for SNPrs3924999 in patients was GG 77.4%, GA 21.12% and AA 1.44% and showed no association with the disease. Similarly, no genotype association was observed in rs2954041: GG 92.98%, GT 6.89%, TT 0.13% of NRG1. However, one unexpected G allele, 100% guanine (G) with no adenine (A) was found to be present in SNP rs35753505 in both patients and controls. This is an interesting finding that both cohorts display only allele G peak but no peak for allele A in the electropherogram for this SNP. Our results suggest that SNP rs35753505 of NRG1 plays an important role in conferring susceptibility to the schizophrenia in a Pakistani population.
Keywords: Adenine (A), allele, DNA, frequencies, guanine (G), Hardy-Weinberg equilibrium, neuregulin 1, schizophrenia, single nucleotide polymorphism.