Analysis of the ROP and no-ROP controls dataset revealed synergistic interactions between TIMP-1 rs4898–MMP-9 rs17576 (IG = 2.24%) and also between MMP-1 rs1799750–TIMP-1 rs4898 (IG = 1.45%; Figure 2). This evidence concerns the gene MMP9 and retinopathy of prematurity.