Lack of Association Between Dopamine Beta-Hydroxylase (DBH) 19-bp Insertion/Deletion Polymorphism and Risk of Schizophrenia

Objective: Interaction between genetic and environmental factors is considered as major factors in Schizophrenia (SCZ). It has been shown that dopaminergic and noradrenergic neurotransmission dysfunction play an essential role in the SCZ pathogenesis. This study aimed to find the impact of functional 19-bp insertion/deletion (ins/del) polymorphism in dopamine beta-hydroxylase (DBH) gene on SCZ risk in a sample of Iranian population. Method: This case-control study was conducted on 109 SCZ patients and 116 matched healthy subjects. Genomic DNA samples were extracted from peripheral blood cells using salting out method. Genotyping of 19-bp ins/del DBH polymorphism was done using Polymerase Chain Reaction (PCR) method. Results: Neither the overall chi-square comparison of cases and controls (𝜒2 = 0.56, p = 0.756), nor the logistic regression analysis (which was computed in codominant, dominant and recessive model of inheritance) showed any association between DBH 19-bp I/D and SCZ in a sample of southeast Iranian population. Conclusion: Overall, our results did not support an association between DBH 19-bp I/D polymorphism and risk/protection of SCZ.