ITIH3 and ITIH4 polymorphisms and depressive symptoms during pregnancy in Japan: the Kyushu Okinawa Maternal and Child Health Study

ITIH3 and ITIH4 are involved in the stabilization of the extracellular matrix. Several genome-wide association studies and case–control studies regarding psychiatric disorders have identified ITIH3 and ITIH4 single nucleotide polymorphisms (SNPs). The present case–control study examined the relationship between ITIH3 SNPs rs2535629 and rs736408 and ITIH4 SNPs rs3821831 and rs2239547 and depressive symptoms during pregnancy in Japan. Cases comprised 273 women with depressive symptoms during pregnancy defined as a Center for Epidemiological Studies Depression Scale (CES-D) score ≥ 16. Control subjects comprised 1176 women without depressive symptoms during pregnancy, according to the CES-D criteria, who had not been diagnosed with depression by a doctor. Adjustment was made for age, gestation at baseline, region of residence, the presence of children, family structure, smoking, employment, and education. Compared with the TT genotype of ITIH4 SNP rs2239547, the CC genotype was significantly related to a reduced risk of depressive symptoms during pregnancy: the adjusted odds ratio (95% CI) was 0.84 (0.63–1.11) for the TC genotype and 0.57 (0.36–0.91) for the CC genotype. ITIH3 SNPs rs2535629 and rs736408 and ITIH4 SNP rs3821831 were not related to depressive symptoms during pregnancy. The GCCT haplotype of rs2535629, rs736408, rs3821831, and rs2239547 was significantly positively associated with depressive symptoms during pregnancy. A significant interaction was found between rs2239547 and the presence of children. This is the first study to show significant associations of ITIH4 SNP rs2239547 and the GCCT haplotype with depressive symptoms during pregnancy. The effect of the presence of children might depend on rs2239547.