HBV genotyping (A,B, C)

Based on phylogenetic test of the nucleotide sequences of the complete genome, hepatitis B virus (HBV) is subdivided into 10 genotypes, designated by the Latin letters A through J. Each genotype is characterized by a specific geographical and ethnic area of prevalence. The most common are 4 genotypes: A, B, C and D. Genotype A is prevalent in North America, Western Europe and Central Africa. Genotypes B and C are typical for China and Southeast Asian countries. Genotype D dominates in the countries of Eastern Europe, the Mediterranean and India. Other genotypes are less common: E, F, G, H, I and J. Genotype E is in West Africa, genotype F is in South America and Alaska, and genotype H is among Central Americans. Genotypes I and J are found in Southeast Asian countries. The prevalence of genotype G has not been sufficiently studied.

Diseases caused by different genotypes of the hepatitis B virus may differ in clinical course and outcomes. Hepatitis B caused by genotype C is more likely to take a chronic course and has a greater risk of transformation into cirrhosis of the liver or hepatocellular carcinoma compared with the disease caused by other genotypes. The genotype of the hepatitis B virus may affect the effectiveness of treatment of chronic hepatitis B (CHB) with interferon drugs. Patients infected with genotype A virus respond significantly better to treatment with interferon drugs compared to patients infected with a virus of other genotypes. Depending on the identified genotype, the tactics of therapy are determined.