As a consequence, the relative mRNA expression ratios of KLK1/KLK10 in the ROP+ACEi group (1.63-fold ± 0.40) were significantly higher than in the ROP-Ctrl group (0.68-fold ± 0.24) (P = 0.0275). The gene discussed is KLK1; the disease is retinopathy of prematurity.