Role of FDFT1 polymorphism for fibrosis progression in patients with chronic hepatitis C.

ABSTRACT

BACKGROUND: In chronic hepatitis C (CHC), steatosis is associated with fibrosis and impaired response to antiviral therapy. Recently, a polymorphism of single nucleotide polymorphism SNP rs2645424 of farnesyl diphosphate farnesyl transferase 1 (FDFT1) was identified in NAFLD/NASH as a possible causal link to steatosis and fibrosis progression. SNP rs738409 in the adiponutrin gene (PNPLA3) is a well described factor for steatosis. This study evaluated the relation of these SNPs on steatosis, fibrosis and treatment response in CHC. METHODS: The SNPs rs738409478 and rs2645424 were determined by real-time PCR in 478 patients with CHC (m/f 314/164; mean age 44.9 ± 10.7; GT1 387, GT4 91) who completed treatment with peg-IFN-α-2a/ribavirin. All had a pretreatment liver biopsy. Steatosis and fibrosis were graded by board-certified pathologists according to Brunt and METAVIR respectively. RESULTS: The distribution of FDFT1 rs2645424 was GG 186 (38.9%), AG 222 (46.4%) and AA 70 (14.6%) and of the rs738409 PNPLA3 allele CC 269 (56.3%), CG 177 (37.0%) and GG 32 (6.7%). Overall, FDTF1 polymorphism was not linked to the extent of steatosis or fibrosis. However, in patients without steatosis the AA genotype was associated with advanced fibrosis [AA 8/20 (40.0%), AG 6/70 (8.5%), GG 9/57 (16.1%), P = 0.003]. In contrast, the minor PNPLA3 allele was associated with both steatosis and advanced fibrosis (P < 0.001). Both SNPs did not influence treatment response. CONCLUSION: The minor allele in FDFT1 was associated with advanced fibrosis in the non-steatotic but not in the steatotic subgroup. This may reflect different metabolic pathways in fibrosis progression for steatotic and non-steatotic patients with CHC.