HLA-DRB1 association with schizophrenia in Saudi Arabian patients

Objective. This study is aimed to examine the association between HLA-DRB1 alleles frequency and schizophrenia in Saudi Arabs. Methods. The DRB1 region of major histocompatibility complex was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) in 180 schizophrenia patients and 200 matched controls. Results. The frequency of DRB1**03 was found to be significantly higher in schizophrenia patients as compared to controls, whereas a significantly lower frequency of DRB1**06 was observed in schizophrenia patients as compared to controls. Molecular sub-typing of the most prevalent allele DRB1**03 (30.56%) revealed the presence of DRB1**030101, **030102 alleles. Conclusion. The results of this study suggested a positive association between DRB1**03 (DRB1**030101, DRB1**030102) with schizophrenia and a negative association of DRB1**06 with schizophrenia in Saudi Arabs. However it is not clear whether the DRB1**03 alleles have a direct causal role in the etiology of schizophrenia or if they are in direct linkage disequilibrium with another true susceptibility locus. Since schizophrenia is a complex phenotype, it is expected that many factors might act together to produce the final outcome. Further studies are warranted involving larger population to confirm the observations reported in this study.