Further evidence for the genetic association between CACNA1I and schizophrenia

Background: Recent large-scale genome-wide association studies (GWAS) have showed that the neuronal calcium signaling has pivotal roles in schizophrenia (SCZ) in populations of European of ancestry. However, it is not known if calcium signaling pathway genes are also associated with SCZ in Han Chinese population.

Methods: Here we investigated the association between genetic variants in three calcium signaling pathway genes (CACNB2, CACNA1C and CACNA1I) and SCZ in 1615 SCZ cases and 1597 controls.

Results: A single nucleotide polymorphism (SNP) (rs4522708) in CACNA1I is significantly associated with SCZ in our Chinese sample (OR_{A allele} = 1.19, corrected P = 0.042), suggesting that CACNA1I may also be a risk gene for SCZ in Chinese population. Of note, the risk allele (A allele) of SNP rs4522708 is same in European and Chinese populations. Meta-analysis of Chinese and European samples further strengthened the association of rs4522708 with SCZ (OR_{A allele} = 1.074, P = 6.26 × 10^-11). Expression analysis showed that CACNA1I was significantly up-regulated in hippocampus of SCZ cases compared with controls, implying that dysregulation of CACNA1I may have a role in schizophrenia pathogenesis.

Conclusions: Our study suggests that CACNA1I is a risk gene for SCZ in Chinese population and provides further evidence that supports the potential role of neuronal calcium signaling in schizophrenia.