Genotype E: The neglected genotype of hepatitis B virus

Table 1 Recombination events of genotype E with breakpoints across the genome

Parental genotype	Region	Genome position (from the EcoRI site)	Country
D/E	preS1		Niger, Ghana, Gabon, and Sudan[53-58]
D/E	preC/C		Ireland[59] and South Africa[60]
D/E	Pol	978, 1230	Sudan[56]
	X	1643
	C/Pol overlapping region	2384
	Pol	2756
	preS1/Pol overlapping region	3000
D/E	X/preC overlapping region	1649, 1932	Niger[58]
	C/Pol overlapping region	2392, 2385
	Pol	2831, 2836
	Pol/preS1 overlapping region	3075, 3083
D/E	X	1651	Ghana[57]
	C/Pol overlapping region	2406
	Pol	2823
	Pol/preS1 overlapping region	3081
E/D	preS	85-505	Niger[58]
	S-Pol overlapping region	796-1306
A/E	C		Ghana[57]
A/E	Pol	874-1062	Cameroon[37]
	X
E/A	Pol	908-1026
	X-C
A/E	preC/C		Guinea[57] and France[61]
E/A	X

The precore/core (preC/C) encodes the e antigen (HBeAg) and core protein (HBcAg); Pol for polymerase (reverse transcriptase), preS1 encodes the large surface protein and X is a transcriptional transactivator protein.

Table 2 Comparison of the virological and clinical characteristics of genotype E with other genotypes

	Genotypes
	E	A	B	C	D	F	G	H
HBV DNA level	Increased	Decreased	Decreased	Increased	Not studied	Not studied	Not studied	Not studied
Frequency of precore G1896A mutation	Increased1	Decreased	Increased	Decreased	Increased	Not studied	Not studied	Not studied
Frequency of basic core promoter T1762A/A1764G mutation	Not studied	Increased	Decreased	Increased	Decreased	Not studied	Not studied	Not studied
Frequency of preS deletion mutation	Not studied	Increased	Decreased	Increased	Not studied	Not studied	Not studied	Not studied
Tendency of chronicity
High		+		+
Low			+		+
Not studied	+					+	+	+
HBeAg positivity
High	+			+
Low		+	+		+
Not studied						+	+	+
HBeAg seroconversion
Early		+	+
Late				+	+
Not studied	+					+	+	+
HBsAg seroconversion
More		+	+
Less				+	+
Not studied	+					+	+	+

¹Relative to D3.

+: Classification of category; preS: Surface protein; HBeAg: Hepatitis B e antigen; HBsAg: Hepatitis B surface antigen. Adapted from Yousif et al[53,54], Shimakawa et al[72] and Schaefer et al[82].