Linked Intronic Polymorphisms of the PNPLA3 Gene Are Associated with Serum Markers of Liver Injury in Patients with Spontaneous HCV Clearance

Genetic variation in PNPLA3 influences liver fat accumulation and hepatocellular injury in various liver diseases. However, the role of PNPLA3 intronic polymorphisms in hepatic damage among hepatitis C virus (HCV) patients remains unclear. This study aims to investigate the association of three intronic PNPLA3 polymorphisms (rs4823173, rs2896019, and rs2281135) with liver injury in HCV-infected patients with spontaneous HCV clearance (SC) and chronic hepatitis C (CHC). A total of 218 HCV-positive individuals were classified into SC (n = 64) or CHC (n = 154) groups. PNPLA3 genotypes were determined by qPCR using TaqMan probes and liver damage through serum markers, noninvasive index, and liver stiffness. Among SC patients, the genotypes AA-rs4823173, GG-rs2896019, and AA-rs2281135 were associated with higher AST, ALT, and APRI, as well as decreased platelet counts, compared with patients homozygous for the non-risk genotypes (p < 0.05). No associations were found in CHC patients. The three polymorphisms were in perfect linkage disequilibrium (r2 = 1). The risk haplotype AGA was associated with higher AST and ALT, as well as lower platelet counts (p < 0.05) in SC patients. PNPLA3 intronic polymorphisms and their association with serum liver injury markers could help identify hepatic injury in HCV-negative patients.