Knowing that different HCV genotypes respond differently to interferon antiviral therapy [21] and based on the aformetioned information we aimed to investigate for the first time the influence of SNPs in CYP2R1 gene, VDR gene, OASL gene and ADAR gene as well as IL28B gene, serum 25-OH vitamin D levels, serum levels of AFP and insulin resistance in treatment outcomes of Egyptian CHC G4 patients treated with Peg-IFN and RBV. The gene discussed is IFNL3; the disease is cryohydrocytosis.