A hepatitis C patient's RNA is detectable by RT-PCR (HCV RNA 1.2×10^5 IU/mL). Genotype testing is performed by sequencing the NS5B and Core-E1 region. Why is genotyping clinically important in HCV management?
- A Genotype predicts severity of liver fibrosis
- B Genotype is required before starting ribavirin monotherapy
- C Genotype determines choice and duration of direct-acting antiviral (DAA) therapy ✓
- D Genotype determines which organ is at risk of extra-hepatic manifestations
Explanation
HCV has 7 genotypes (1–7) with multiple subtypes. Historically, genotype guided selection of interferon-based regimens (e.g., genotype 1 required longer treatment). With pan-genotypic DAA regimens (sofosbuvir/velpatasvir; glecaprevir/pibrentasvir), genotyping is less critical for treatment selection but remains important for: (1) identifying pangenotypic vs. genotype-specific regimens, (2) assessing resistance-associated substitutions in NS5A region for genotype 1a/3 (where pre-treatment resistance testing impacts DAA choice), and (3) epidemiological surveillance. Treatment with DAAs achieves >95% SVR12 (sustained virological response at 12 weeks = cure).
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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