NGF and retinopathy of prematurity: Epistatic interactions between carriers of NGF (GG) and BDNF (allele G), as well as between carriers of NGF (GG), BDNF (allele G), and TH (allele C), demonstrated significant differences in the percentages of immature granulocytes between infants who developed ROP and those who did not (Table 8 and Table 10).