COL3A1 and major depressive disorder: The most robust associations were observed for rs16830979 in COL3A1 ( p < 0.001, odds ratio [OR] = 1.56) and rs16830219 in COL6A6 ( p < 0.001, OR = 0.56), suggesting a strong genetic contribution of these SNPs to ECM degradation pathways in the pathophysiology of MDD (Table 4).