To examine whether the SNP genotypes associate with gene expression for CDH10 and CDH9, we next examined the SNPExpress database32 that profiles gene expression in 93 human cortical brain tissues from genotyped subjects. However, none of the SNPs in Table 2 was associated with expression levels for either CDH9 (P = 0.92 for rs4307059) or CDH10 (P = 0.86 for rs4307059) (Fig. 2b). Although the small sample size may not have sufficient power to detect subtle effect sizes, it is also possible that the causal variants regulate gene expression only in the developing brain, or that the causal variants target an unidentified functional element, similar to the variants reported in the intergenic region on 8q24, which have been implicated in various cancers33,34.
