Frequencies of an IFNL4 Variant in an Admixed Population from Amazonia and Its Influence on Hepatitis C Infection

The rs12979860 polymorphism, related to the <i>IFNL4</i> gene, is suggested as a factor that impacts fibrosis progression in hepatitis C virus (HCV) infection and exhibits a wide distribution pattern across global populations. In this retrospective cross-sectional study, we aimed to investigate the frequency of this variant in an Amazonian population from Brazil, as well as its association with liver fibrosis development and its staging in HCV carriers. Our results show a significant association of the TT genotype in the sample of patients with HCV (OR = 2.291; 95% CI = 1.088-4.826; <i>p</i> = 0.033) and the greater frequency of the T allele (62.1%), which is similar to the those of African populational groups. Populational genetics analysis showed significant differences in allele frequencies on global levels. The frequency of the C allele in the study population (37.8%) was like that of the African population (39.7%), and differed from all other populations, which ranged from 62.5% to 92.9%. These findings suggest that rs12979860 plays a role in susceptibility to hepatitis C. Additionally, they allow us to propose that the response to hepatitis C infection in this group may resemble that of the African population.