Hepatitis C Virus: Biological and Clinical Consequences of Genetic Heterogeneity.

Hepatitis C Virus infection accounts for the majority of post-transfusion and sporadic hepatitis. In Western Europe, anti-HCV is detected in 0.4–1.5% of healthy blood donors. There is a high frequency of progressive chronic hepatitis, ranging from 50 to 80%, which leads to cirrhosis in 20–50% of patients after 10–20 years. Viremic patients with minimal biochemical abnormalities may have chronic liver disease histologically. There is growing evidence that virological features of HCV are associated with different clinical manifestations and response to therapy. The RNA genome consists of a 5′ and 3′ Untranslated Region, a structural domain encoding the core and envelope proteins, and a non-structural domain. Different HCV isolates show a high sequence heterogeneity, which has led to the classification of currently six genotypes and several subtypes. There is a marked difference in the geographic distribution of HCV genotypes, with types 1, 2 and 3a being most frequently found in western countries. In The Ne...