Objective: The present study investigated two single nucleotide polymorphisms (SNPs) of the histamine H4 receptor (HH4R) gene in schizophrenia patients who have been treated with typical and atypical drugs.

Material and Method: This study was conducted in 60 schizophrenia patients treated with typical antipsychotic (30) and atypical antipsychotic (30) drugs. The DNAs were extracted from whole blood using Flexigene DNA kit (Qiagen, Germany) and genotyped by polymerase chain reaction (PCR) followed by high-resolution melting (HRM) analysis. The difference in genotypic and allelic distribution between patients treated with typical and atypical antipsychotic drugs were assessed by Chisquare test using SPSS software version 11.5.

Results: The result revealed that two SNPs (rs8088140 and rs657132) in intronic region of HH4R gene are significant associated with appropriate treatment of schizophrenia patient with typical or atypical antipsychotic drugs. The rs8088140 SNP showed significant at p-value = 0.034, with odd ratio value and 95% CI [2.82 (1.34 to 5.95)], whereas the rs657132 SNP displayed significant at p-value = 0.039, with odd ratio value and 95% CI [2.25 (1.08 to 4.67)].

Conclusion: Two SNPs in HH4R gene (rs8088140 and rs657132) may be used to indicate the proper antipsychotic drugs for treatment of Thai schizophrenia patients.

Keywords: Schizophrenia, Single nucleotide polymorphism, Histamine H4 receptor, Antipsychotic drug, High-resolution melting analysis