title: Hepatitis C virus variants from Thailand classifiable into five novel genotypes in the sixth (6b), seventh (7c, 7d) and ninth (9b, 9c) major genetic groups.
abstract: Nine (10%) out of 90 hepatitis C virus (HCV) isolates from hepatitis patients and commercial blood donors in Thailand were not classifiable into any of genotypes I/1a, II/1b, III/2a, IV/2b, V/3a or VI/3b by RT-PCR with type-specific primers deduced from the HCV core gene. These isolates were sequenced over a 1.6 kb stretch of the 5'-terminal sequence and 1.1 kb of the 3'-terminal sequence covering 30% of the entire genome. Based on two-by-two comparison and phylogenetic analyses of the nine Thailand isolates among themselves and with known full or partial sequences of previously reported HCV isolates, the Thailand isolates were classified into five genotypes not reported previously, viz. 6b, 7c, 7d, 9b and 9c. Along with HCV isolates reported already, they make at least nine major genetic groups of HCV which further break down into at least 28 genotypes with sequence similarity in the E1 gene (576 bp) of < or = 80%. As many more HCV isolates of distinct genotypes are expected to be found throughout the world, it will become increasingly difficult to classify them by comparison of any partial sequences of the genome. Complete sequence data will be required for the full characterization and classification of HCV genotypes.
authors.affiliation: Immunology Division, Jichi Medical School, Tochigi-Ken, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tokita
authors.forename: H
authors.initials: H
authors.lastname: Okamoto
authors.forename: P
authors.initials: P
authors.lastname: Luengrojanakul
authors.forename: K
authors.initials: K
authors.lastname: Vareesangthip
authors.forename: T
authors.initials: T
authors.lastname: Chainuvati
authors.forename: H
authors.initials: H
authors.lastname: Iizuka
authors.forename: F
authors.initials: F
authors.lastname: Tsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Miyakawa
authors.forename: M
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics; D014644:Genetic Variation; D016679:Genome, Viral; D016174:Hepacivirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013785:Thailand; D014758:Viral Core Proteins / Q000235:genetics; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; C087035:E1 protein, Hepatitis C virus; D014758:Viral Core Proteins; D014759:Viral Envelope Proteins; C069130:nucleocapsid protein, Hepatitis C virus; C091015:glycoprotein E2, Hepatitis C virus