Overview of hepatitis B virus mutations and their implications in the management of infection

Table 1 Cross-resistance data for the most frequent resistant hepatitis B virus variant

HBV variants	Level of susceptibility
	Lamivudine	Telbivudine	Entecavir	Adefovir	Tenofovir
Wild-tipe	S	S	S	S	S
M204V	R	S	I	I	S
M204I	R	R	I	I	S
L180M + M204V	R	R	I	I	S
A181A/T	I	S	S	R	S
N236T	S	S	S	R	I
L180M + M204V/I ± I196T ± V173L ± M250V	R	R	R	S	S
L180M + M204V/I ± T184G ± S202I/G	R	R	R	S	S

The amino-acid substitution profiles are shown in the left column and the level or susceptibility is given for each drugs: S (sensitive), I (intermediate/reduced susceptibility), R (resistant). EASL Clinical Practice Guidelines 2012.

Table 2 Impact of drug resistant mutations in the the hepatitis B virus Pol on the hepatitis B surface antigen

Antiviral drugs	Resistance mutations	HBsAg correspondingchanges
Lamivudine (LAM2) Tebivudine (LdT2)	rtL180M	No change
	rtM204V	sI195M
	rtM204I2	sW1961/S/L
Adefovir (AdV) Tenofovir (TDF) LAM2	rtA181T2	sW1721
	rtA181T2	sW172L
	rtA181V2	sL173F
	rtN236T	After end of HBs open reading frame
Entecavir (ETV)	rtI169T	sF161H/L
	rtT184A	No change
	rtT184C	sL175F + sL176V
	rtT184I	No change
	rtT184G	sL176V
	rtT184S	sL175F
	rtT184M	sL1761
	rt184L	sL175F
	rtS202C	No change/sS193F
	rtS202I	sV194F/S
	rtS202G	No change/sS193L
	rtM250I	After end of HBs open reading frame
	rtM250V	After end of HBs open reading frame

¹Stop codon;

²Cross-resistance. HBsAg: Hepatitis B surface antigen. Modified from Zoulim et al[38].