Article Highlight | 24-Sep-2026

Molecular basis and clinical significance of the high-risk phenotype of hepatitis B virus genotype C

Xia & He Publishing Inc.

Molecular Basis and Clinical Significance of the High-risk Phenotype of Hepatitis B Virus Genotype C

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HBV genotype C represents a clinically relevant high-risk form of chronic HBV infection. It is generally associated with delayed HBeAg seroconversion, persistent viral replication, more active hepatic inflammation, faster fibrosis progression, and a higher risk of HCC. Importantly, this risk may persist even after effective antiviral suppression, especially in patients with advanced fibrosis or cirrhosis. The high-risk phenotype of genotype C appears to be related to its viral sequence background, enrichment of BCP/preC/HBx-related variants, altered HBeAg expression, immune dysregulation, HBx-related oncogenic signaling, and HBV integration-associated genomic instability. Although these mechanisms are not exclusive to genotype C, they may be more clinically relevant in genotype C infection because of the prolonged replication phase, enrichment of high-risk viral variants, and greater cumulative inflammatory and oncogenic injury. In clinical practice, genotype C should be viewed as a risk-enhancing virological factor rather than a stand-alone determinant of treatment or surveillance decisions. Combining genotype information with viral mutations, fibrosis stage, cirrhosis status, treatment response, and emerging biomarkers may help refine long-term risk assessment and surveillance planning for patients with chronic hepatitis B.

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Credit: Lei Sang, Tao Shen

HBV genotype C is common in East Asia and linked to cirrhosis and HCC. It features persistent replication, delayed HBeAg seroconversion, active inflammation, and high HCC risk. Key drivers include BCP A1762T/G1764A, preC G1896A, abnormal HBx, and viral integration. This review summarises the molecular features, pathogenic mechanisms, and clinical implications, and discusses genotype‑informed risk stratification.

Introduction

CHB progression varies widely. Viral factors, especially genotype and mutations, are key determinants. Genotype C is associated with poorer outcomes. BCP/preC mutations produce high replication with low HBeAg expression; HBx dysfunction and viral integration contribute to inflammation and hepatocarcinogenesis.

Virological Features

Distribution: Predominant in Asia/Oceania. Subgenotypes: C1 (Southeast Asia), C2 (China, Korea, Japan), C3/C4 (Oceania). Mixed infection may increase replication and inflammation.

Genome: ~3.2 kb circular DNA with four overlapping ORFs. In genotype C, sequence background influences emergence of regulatory mutations. PreC and BCP are critical for HBeAg expression and replication. A1762T/G1764A is more frequent in genotype C. Nucleotide 1858 (C in genotype C, T in B) affects G1896A stability.

Key mutations:

  • BCP A1762T/G1764A: Reduces HBeAg, enhances pgRNA and replication; causes HBx K130M/V131I. Associated with increased HCC risk, stronger in genotype C.

  • preC G1896A: Stop codon, abolishes HBeAg. Constrained by ε stem‑loop; less frequent and later in genotype C. Marker of HBeAg‑negative CHB.

  • Synergy: Co‑occurrence of BCP and preC mutations increases cirrhosis/HCC risk.

  • Quasispecies: Viral diversity under immune pressure promotes accumulation of high‑risk variants.

Molecular Mechanisms

  • HBeAg loss and immune dysregulation: Reduced HBeAg disrupts immune tolerance, causing persistent ineffective inflammation, repeated hepatocyte injury, and fibrosis.

  • HBx/BCP variants: Activate Wnt/β‑catenin (via APC/GSK3β, SFRP1/5 repression) and JAK/STAT3 (via ROS, mitochondrial dysfunction). K130M/V131I and truncated HBx enhance oncogenic signalling.

  • Host disturbances: Epigenetic changes, DNA damage response defects, p53 dysfunction, autophagy abnormalities cooperate.

  • Viral integration: Detectable in ~85–90% of HBV‑related HCC. Integration is a byproduct of DNA repair; X‑gene fragments produce truncated HBx. Recurrent genes include TERT, KMT2B/MLL4, PLEKHG4B. Integration alone is insufficient to define a driver.

Clinical Consequences

  • Natural history: Longer immune‑active phase, delayed HBeAg seroconversion, faster fibrosis/cirrhosis than genotype B.

  • HCC risk: Independent risk factor vs. genotype B (HR ≈ 2.35; meta‑analysis OR ≈ 2.05).

  • Antiviral therapy: Nucleos(t)ide analogues suppress replication but do not eliminate residual HCC risk, especially with cirrhosis. Integrated HBV DNA and clonal expansion persist. Biomarkers (qHBsAg, HBcrAg, HBV RNA) may help but are not standardised.

  • Risk stratification: Genotype C is a risk modifier, not a stand‑alone marker. Combine with age, sex, family history, HBV DNA, ALT, fibrosis, cirrhosis, metabolic factors, and treatment response.

  • Management: Six‑monthly ultrasound remains standard. Genotype C justifies strict surveillance adherence and active risk reassessment, not automatic interval shortening. It is not a single treatment indication but may support earlier reassessment in borderline cases.

Perspectives

Most evidence treats genotype C as one category; subgenotype C2 data are limited. Future priorities: validate genotype‑informed risk models; clarify residual risk mechanisms; test Wnt/STAT3 targeting; define role of immunotherapy; assess feasibility of routine genotyping.

Conclusions

Genotype C is a high‑risk form of CHB, associated with delayed HBeAg seroconversion, persistent replication, active inflammation, faster fibrosis, and higher HCC risk—persisting after viral suppression. Its phenotype relates to BCP/preC/HBx variants, immune dysregulation, oncogenic signalling, and integration‑associated genomic instability. Genotype C should be viewed as a risk‑enhancing factor, not a stand‑alone determinant. Combining genotype with viral mutations, fibrosis, cirrhosis, treatment response, and emerging biomarkers may refine long‑term risk assessment and surveillance.

 

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https://www.xiahepublishing.com/2310-8819/JCTH-2026-00247

 

The study was recently published in the Journal of Clinical and Translational Hepatology.

The Journal of Clinical and Translational Hepatology (JCTH) is owned by the Second Affiliated Hospital of Chongqing Medical University and published by XIA & HE Publishing Inc. JCTH publishes high quality, peer reviewed studies in the translational and clinical human health sciences of liver diseases. JCTH has established high standards for publication of original research, which are characterized by a study’s novelty, quality, and ethical conduct in the scientific process as well as in the communication of the research findings. Each issue includes articles by leading authorities on topics in hepatology that are germane to the most current challenges in the field. Special features include reports on the latest advances in drug development and technology that are relevant to liver diseases. Regular features of JCTH also include editorials, correspondences and invited commentaries on rapidly progressing areas in hepatology. All articles published by JCTH, both solicited and unsolicited, must pass our rigorous peer review process.

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