Association of interleukin 3 (IL-3) polymorphisms with schizophrenia in Han Chinese population

Schizophrenia has been observed to be associated with various abnormalities in multiple cytokines. Recent genetic analyses showed that the interleukin 3 (IL-3) gene and its receptors are significantly associated with schizophrenia, especially in Irish populations. To examine the associations of the Irish-risk single nucleotide polymorphisms (SNPs, e.g., rs3916441) in the IL-3 gene with schizophrenia in Chinese population, we utilized two independent samples from Southwestern China, including a total 901 schizophrenia patients and 1417 healthy controls. However, no statistically significant differences were observed in allelic or genotypic frequencies of the tested 6 SNPs in IL-3 between cases and controls in any sample. Therefore, the results of our analyses were not able to confirm the association of IL-3 SNPs with schizophrenia. The absence of the IL-3's association in Chinese population suggest a potential genetic heterogeneity in the susceptibility of schizophrenia on this locus and also demonstrate the difficulties in replicating associations of schizophrenia across different ethnic populations.