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Nomenclature recommendations

Consensus nomenclature of HCV genotypes and subtypes:

This page contains nomenclature recommendations from the Nomenclature Meeting hold on Tuesday, October 5th 2004 (Simmonds P, et al., Hepatology, 2005).

You will find the recommendation for classification of new genotypes and new subtypes as well as the known genotypes/subtypes (table 1 and table 3) and changes made in some genotype/subtype names (table 2).

Classification proposals for new genotypes:
  • Less frequent occurrence that finding of new subtypes
  • Provisional classification:
    • Complete genome sequence for one example
    • Rigorous testing of branching order at the base of the tree, and for inter-genotype recombination
    • Assignment of next genotype number
  • Confirmed designation
    • Two or more complete genome sequence
    • Investigation of subtype diversity and geographical origin
Classification proposals for HCV subtypes:
  • Provisional classification of new subtypes:
    • Three or more examples of epidemiologically unliked infections
    • Sequence datat from core/E1 and NS5B regions ( > 90% complete sequence from 869-1292 and 8276-8615 in AF009606)
    • 5'UTR sequence useful but not essential
    • Assignment of next available subtype letter
  • Confirmed designation
    • Complete genome sequence from one or more new subtype variants
    • Confirmation of absence of recombination
List of assigned HCV subtypes:
Genotype (total=7) Subtype (total=84)
1 a,b,c,d,e,f,g,h,i,j,k,l,m (13)
2 a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r (18)
3 a,b,c,d,e,f,g,h,i,k (10)
4 a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u (21)
5 a (1)
6 a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t (20)
7 a (1)
In red confirmed subtypes (table 1) in Simmonds P, et al. (Hepatology, 2005).
In black provisionally assigned subtypes (table 3) in Simmonds P, et al. (Hepatology, 2005).
In blue provisionally assigned subtypes since Simmonds P, et al. (Hepatology, 2005).
In green confirmed subtypes since Simmonds P, et al. (Hepatology, 2005).
NOTE: tables 1, 2, and 3 were compiled by a working group of Donald Murphy, Erwin Sablon, and Phillipe Halfon.

Numbering system:

A comprehensive system for consistent numbering of HCV sequences, proteins and epitopes has been defined (Kuiken C, et al., Hepatology, 2006). The Number tool implements this numbering system.

PCR primers:

A list of PCR primers suitable for subtype identification is available at the LANL HCV database.