Common variants in the CDH7 gene are associated with major depressive disorder in the Han Chinese population

Cadherin-7 (CDH7) gene encodes a calcium dependent cell-cell adhesion glycoprotein. Gene loci of cadherins family have been supposed to be involved in the pathogenesis of psychiatric disorders. Recent genome-wide association study also demonstrated that CDH7 was significant associated with bipolar disorder. Due to the fact that the same genetic risk factor can be shared by different kinds of psychiatric disorders, we examined whether CDH7 is also associated with major depressive disorder (MDD) in this study, with a large Han Chinese sample set. We carried out a 2-stage case-control study to examine the association between CDH7 and MDD in the Han Chinese population. Ten tag SNPs were genotyped using Taqman technology in 1,045 MDD patients and 1,520 healthy controls. Single-nucleotide polymorphisms with significance were additionally genotyped in another independent sample set with 576 MDD cases and 576 healthy controls. Among ten genotyped SNPs, rs1444067 and rs12605720 was found to be significantly associated with MDD (rs1444067: P(allele) = 0.00571, OR 0.830, 95 % CI 0.728-0.947; rs12605720: P(allele) = 0.00321, OR 1.245, 95 % CI 1.076-1.441). We successfully replicated these two SNPs association with independent sample sets (rs1444067: P(allele) = 0.00518; rs12605720: P(allele) = 0.0227). Finally we have combined these results by a meta-analysis (rs1444067: P(allele) = 0.000174, OR 0.817; rs12605720: P(allele) = 0.000199, OR 1.255). Our results support CDH7 to be a risk factor of MDD in the Han Chinese population. However, further studies with more markers and independent samples were suggested to validate our findings.