Association of interferon gamma gene polymorphism and susceptibility to hepatitis C virus infection in Egyptian patients: A multicenter, family‐based study

BACKGROUND AND AIM: Polymorphisms in some genes may influence the persistence of hepatitis C virus (HCV) infection, clinical outcome, HCV replication, and liver damage. This study was conducted to investigate the role of the interferon gamma (IFN‐γ) gene at (+874 T/A, −764 G/C, −179 C/A) single‐nucleotide polymorphisms (SNPs) and its receptor (IFN‐γR2) at (rs 2786067 A/C) SNP in the susceptibility of Egyptian families to HCV infection with high‐resolution techniques. METHODS: In total, 517 Egyptian families, with 2246 subjects, were recruited to this study from the Upper and Lower Egypt governorates and were classified into three groups: 1034 patients with chronic hepatitis C virus, 108 subjects with spontaneous virus clearance (SVC), and 1104 subjects as a healthy control group. All subjects were genotyped for (+874 T/A, rs2430561, −764 G/C, rs2069707, −179 C/A, rs2069709, and rs 27860067, A/C) SNPs of the IFN‐γ gene using the allelic discrimination real‐time polymerase chain reaction technique and were confirmed using sequence‐based typing. RESULTS: The carriage of T allele of (+874) IFN‐γ is a risky allele and was significantly higher in chronic hepatitis C more than other two groups (odds ratio [OR]: 2.6646, P < 0.0002). On the other hand, the C allele of (−764, rs2069707) is a protective allele and was higher in SVC than the other two groups (OR: 0.2709, P < 0.0001). However, both (−179 C/A, rs 2069709) and (rs 27860067, A/C) SNPs are not polymorphic enough to be studied in the Egyptian population. CONCLUSIONS: HCV infection is associated with the T allele of (+874 rs2430561), while SVC of HCV is associated with the C allele of (−764, rs2069707) of the IFN‐γ gene.