Association of the PIK4CA schizophrenia‐susceptibility gene in adults with the 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11DS) is associated with an increased prevalence (20-30%) of schizophrenia. Therefore, it is likely that one or more genes within the 22q11.2 region are causally related to schizophrenia. Recently, a significant association with schizophrenia in the general population was reported for three SNPs in phosphatidyl-inositol-4-kinase-catalytic-alpha (PIK4CA), a gene located in the 22q11.2 region. In the current study, we tested the hypothesis that the same PIK4CA risk-alleles would be associated with schizophrenia in individuals with 22q11DS. Our analysis of the PIK4CA genotypes in a sample of 79 adults with typical 22q11.2 deletions, comparing those with schizophrenia to those without, revealed a significant association. Our findings represent an independent replication of the previously reported PIK4CA association with schizophrenia in the general population. Second, the results of this study indicate that variation at PIK4CA may be a relevant factor influencing the risk of schizophrenia in individuals with 22q11DS.