乙型肝炎病毒基因型与YMDD变异的关系

目的:了解乙型肝炎病毒(HBV)基因型与YMDD变异之间的关系.方法:多对型特异性引物PCR扩增法对238例经拉米夫定治疗的慢性乙型肝炎患者进行HBV基因分型,直接序列分析;采用基因芯片检测YMDD及前C/BCP区变异.结果:238例患者中,检测出B基因型190例(79.8%),C基因型41例(17.2%),BC混合型7例(3.0%);发生YMDD变异44例,变异率为18.5%,其中B基因型33例,变异率为17.4%,C基因型8例,变异率为19.5%,BC混合型3例,变异率为42.4%,C基因型YMDD变异的发生率与B基因型相比,差异无显著性意义(P＞0.05).44例YMDD变异者中,30例同时存在L528M变异,7例联合前C区(nt 1 896)变异,13例联合BCP区(nt 1 762/1 764)双重突变.结论:本地区慢性乙型肝炎患者中,优势基因型为B型和C型,经拉米夫定治疗后YMDD变异的发生率在B型和C型差异无显著性意义,同时伴有L528M及前C/BCP区多重变异.     

HBV基因型与干扰素抗病毒疗效的关系

目的:探讨HBV不同基因型对α-干扰素抗病毒疗效的影响.方法:选取应用α-干扰素进行抗病毒治疗的慢性乙型肝炎患者作为研究对象,观察其抗病毒疗效.患者的HBV基因型采用PCR微板核酸杂交-ELISA方法检测;血清HBV DNA复制水平采用荧光定量PCR检测;HBV前C区和BCP(基础核心启动子)区基因位点变异采用HBV基因多态性芯片进行检测.结果:94例慢性乙型肝炎患者的HBV基因型以C型、B型为主,未发现A、E、F基因型.HBV DNA高复制水平明显与C基因型及混合基因型有关.B基因型对α-干扰素抗病毒治疗的应答明显优于C、D型,而混合基因型对α-干扰素的应答最不敏感.仅B基因型对α-干扰素治疗产生完全应答.部分应答及无应答时HBeAg的转阴与HBV前C区nt 1 896位点变异、以及BCP区nt 1 762、nt 1 764双位点变异有关.C基因型HBV前C区及BCP区基因变异发生率明显高于B型.结论:HBV基因型与HBV DNA复制水平、HBV基因变异以及α-干扰素抗病毒疗效均有一定的相关性,提示HBV基因分型有重要的临床意义.     

乙型肝炎病毒基因型、BCP及PC区变异与拉米夫定治疗后HBV DNA反弹的关系

目的:探讨HBV基因型、C区基本核心启动子(BcP)及前C(PC)区变异与拉米夫定抗病毒治疗后HBV DNA反弹的关系.方法:应用多引物对巢式PCR法,PCR-序列分析法,检测拉米夫定治疗27例乙型肝炎患者(治疗组),以及19例从未用过抗病毒治疗患者(对照组)的HBV基因型PC区,BCP的突变位点.结果:27例HBV DNA反弹的患者9例检出G1896A变异率高于对照组(33.33% vs 5.26%,P<0.05),4例检出C1856T变异(14.81%).治疗组4份治疗前标本未检出G1896A、C1856T和BCP变异.与对照组比较,治疗组PC(G1896A)及BCP(A1762T G1764A)双变异的患者中B基因型的构成比增高,分别为75%和50%,C基因型的构成比下降,分别为25%和50%.其中在BCP(A1762T G1764A)变异患者中B、C基因型构成比与对照组比较有显著性差异(P<0.05).4例HBV DNA反弹患者治疗前未检出有基因变异,治疗后有2例检出变异,BCP变异1例,BCP PC变异1例.27例HBV DNA反弹患者BCP变异4例,PC变异2例,BCP PC变异8例.结论:BCP(T1762/A1764)变异、PC区(G1896A)变异可能与拉米夫定治疗后HBV DNA反弹有关.病毒变异导致的HBV DNA反弹可以是单基因变异引起,也可以是多个基因联合变异引起,拉米夫定治疗后B基因型患者更易发生A1762T G1764A变异.     

仙居地区HBV基因型分布与若干相关问题的研究

目的:调查浙江仙居地区HBV基因型的分布,研究基因型与前C区变异的关系及基因型的临床稳定性.方法:全部病例样本均取自仙居地区出生的汉族人,HBV基因型及前C区变异均采用型特异性PCR法;部分病例分别于3、6、12、18月,重复采血复查基因型.结果:仙居地区HBV基因型分布:C型283例,B型51例,CB混合型19例;查nt(核苷酸)1 896变异51例,变异阳性者C型9/37例、B型7/10例、混合型3/4例;3、6、12、18月复查基因型,小部分病例发生改变.结论:仙居地区HBV基因型的分布,以C型为主占80.2%,其次为B型与CB混合型,分别占14.4%与5.4%;B型与CB混合型容易发生HBVnt 1896变异;基因型临床稳定性值得进一步研究.     

HBV基因型及A1762T/G1764A双位点变异在肝癌患者中的临床意义

目的:研究肝细胞癌(HCC)患者乙型肝炎病毒(HBV)基因型与基本核心启动子(BCP)基因区A1762T/G1764A双位点变异(BCP区双突变)之间的关系,探讨HCC的发病机制。方法:选择40例HCC患者作为研究组,40例慢性乙型肝炎(CHB)患者作为对照组,采用多对型特异性引物PCR扩增法进行基因分型及HBV基因多态性芯片检测BCP区A1762T/G1764A双位点变异。结果:40例HCC患者中有30例HBV DNA定量阳性,平均对数值为(6·53±1·31)copy/ml,将30例HBV DNA定量阳性的HCC及40例CHB患者的血清进行HBV基因分型及基因变异检测,结果显示30例HCC中HBV B基因型5例(16·7%),C基因型25例(83·3%);BCP区双突变共有20例(67·7%),其中B基因型1例,C基因型19例,BCP双突变率在B基因型和C基因型中分别为20%(1/5)和76%(19/25);40例CHB患者中B基因型32例(80%),C基因型8例(20%);BCP区双突变共有13例,其中B基因型8例,C基因型5例,BCP双突率在B基因型和C基因型中分别是25%(8/32)和62·5%(5/8)。结论:肝细胞癌的发生与BCP区A1762T/G1764A双位点变异有关,多发生在HBV C基因型的患者。     

乙型肝炎病毒前核心区及基本核心启动子变异的检测及其对患者疾病谱的影响

目的探讨乙型肝炎病毒(HBV)前核心区(前C区,nt1896)及基本核心启动子(BCP,nt1762/1764)变异在慢性HBV感染者疾病谱的分布及对患者疾病谱的影响。方法416例血清HBsAg阳性、HBVDNA定量大于1.0×104拷贝/毫升的患者,采用微流基因芯片检测HBV前C区及BCP变异。结果416例HBV感染者中302例为HBeAg(-)患者,其中248例(82.12%)有前C区或BCP变异,41.06%为前C区变异,31.12%BCP变异,2种同时变异为9.94%。HBeAg(-)的慢性乙型肝炎和肝硬化患者前C区变异分别为64.72%和83.33%(x2=0.89,P>0.05),均大于HBeAg(-)无症状携带者的28.47%(x2=54.20,P<0.01;x2=5.29,P<0.05);而HBeAg(-)无症状携带者BCP变异达77.19%,大于HBeAg(-)慢性乙型肝炎和肝硬化患者(x2=69.73,P<0.01;x2=10.58,P<0.01)。而在114例HBeAg(+)患者中28.95%有前C区或BCP变异。结论前C区或BCP变异在慢性HBV感染者疾病谱的分布不同,在HBeAg(-)/HBVDNA(+)与HBeAg(+)/HBVDNA(+)患者变异率差异显著。HBV前C区可能是该病变反复及加重的一个重要原因,但BCP变异临床意义不明确。     

慢性乙型肝炎、乙型肝炎肝硬化及原发性肝癌患者HBV-X基因突变分析

目的研究慢性HBV感染者,如慢性乙型肝炎(CHB)、乙型肝炎肝硬化(LC)、原发性肝癌(PLC)患者血清中HBV-X基因序列的突变与肝癌发生的关系。方法收集2011-2013年间于重庆医科大学附属第二医院就诊的慢性HBV感染者血清共89例,从血清中提取HBV DNA,扩增全长HBV-X基因序列,经测序后与已知HBV-X基因相应序列比较该患者体内HBV-X基因变异位点以及变异形式,并用卡方检验、单因素方差分析处理数据,NCBI的genotype工具测定基因型。结果所有患者均属于B/C基因型,HBeAg阳性患者中B基因型占46.2%,C基因型占53.8%;HBeAg阴性患性中B基因型占81.2%,C基因型占18.8%(P=0.001)。在PLC组中,启动子(BCP)区的突变显著高于CHB、LC(69.2%vs34.4%和61.3%,P0.05),且nt1821位点存在明显的T碱基的缺失(88.5%vs 53.1%和71%,P=0.014)。在CHB、LC中,C基因型BCP的双突变率显著高于B基因型(61.5%vs 15.8%,P=0.007;83.3%vs 47.4%,P=0.045),HBV DNA低病毒载量(≤106拷贝/ml)中BCP的突变率较高病毒载量(106拷贝/ml)更显著(81.3%vs 47.9%,P=0.015)。结论 BCP区的双突变及nt1821位点的缺失可能与PLC的发生密切相关。     

39例成人急性乙型肝炎患者血清HBV基因变异检测及其临床意义探讨

目的了解成人急性乙型肝炎患者流行的病毒基因型及基因变异情况。方法在2010年12月~2014年1月北京佑安医院收治39例急性乙型肝炎患者,采用直接基因测序法和平行等位基因特异性检测技术检测HBV基因型、P区、S区、前C区(Pre C)和基本核心启动子(BCP)区序列。结果在39例患者中,成功测序35例。35例急性乙型肝炎患者感染HBV B基因型12例(36.4%),C基因型21例(57.6%,D基因型2例(6.0%);通过直接测序法和PASS法均检测到同1例患者存在A181S耐药变异,变异病毒占准种池比例达100%;直接测序法检测到1例患者存在S区S132F和W172C变异;1例患者存在Pre C/BCP区G1896A和T1758C变异。结论急性乙型肝炎患者感染病毒基因型与文献报道的慢性乙型肝炎患者感染病毒基因型分布一致,以C型和B型为主,存在P区、S区和Pre C/BCP区变异可能,未见不同病毒株感染引起转归的不同。     

乙型肝炎病毒基因型检测及其临床应用

目的:探讨HBV基因型的检测及其在临床上的应用.方法:用微板核酸分子杂交-ELISA方法检测468例HBV DNA阳性的慢性乙型肝炎患者血清HBV基因型.分析HBV基因型与病毒复制、基本C基因启动子(BCP)变异、肝病病情轻重、干扰素疗效的关系.结果:深圳地区HBV基因型以B和C基因型为主,分别占25.0%和64.9%;C基因型的HBeAg阳性率(68.8%)高于B基因型的HBeAg阳性率(35.0%)(P＜0.01);C基因型的血清HBV DNA水平也明显高于B基因型(1g 6.74 copies/ml vs. 1g 5.44 copies/ml, P＜0.01);轻中度慢性肝炎以B基因型为主,而重度慢性肝炎以C基因型为主;B基因型对干扰素的有效应答率为47.2%,C基因型的有效应答率为28.9%,两组比较差异有显著性意义(P＜0.05).结论:HBV基因分型有助于临床判断病情、估计预后及抗病毒治疗疗效预测.     

秦皇岛市136例慢性乙型肝炎患者拉米夫定的疗效及其与HBV基因型的关系

目的:探讨秦皇岛市慢性乙型肝炎(CHB)患者拉米夫定治疗疗效与基因型的关系。方法:136例CHB患者口服拉米夫定,100mg/次,1次/d,疗程48周,用药前采用PCR方法测定乙型肝炎病毒(HBV)A～D基因型。结果:秦皇岛市CHB患者基因型以C型为主,占75.74%,其次为B基因型占16.91%,B/C混合型占7.35%,B基因型在拉米夫定抗病毒治疗48周时显示HBV DNA阴转率、HBeAg血清转换率、ALT复常率、治疗有效率4方面均高于C型及B/C基因型(P0.05),B基因型HBV感染者有较低的YMDD变异发生率。结论:拉米夫定抗病毒疗效与基因型有关,HBV基因型测定可作为预测拉米夫定抗病毒疗效的指标。     

Effects of hepatitis B virus precore and basal core promoter mutations on the expression of viral antigens: genotype B vs C

Hepatitis B virus (HBV) genotypes/mutants are known to affect natural outcomes. The virologic differences among HBV genotype, precore and basal core promoter (BCP) mutations were investigated. HBV strains were isolated from 18 hepatitis B e antigen (HBeAg)-positive patients (nine genotype B and nine genotype C). All had precore and BCP wild-type sequences. After cloning of full-length HBV genome, the effects of viral genotype, precore and BCP mutations singly or additively on the expression of viral DNA and antigens were investigated by mutagenesis and transfection assays in Huh7 cells. Significant findings included the following: (i) expression of intracellular core protein increased when precore or BCP mutation was introduced in genotype C strains; (ii) expression of intracellular surface protein was lower in genotype C precore wild-type strain compared with genotype B; (iii) precore mutation was associated with a lower extracellular expression level of HBV DNA; (iv) secretion of hepatitis B surface antigen in genotype C was lower than that in genotype B; and (v) secretion of HBeAg in genotype B was lower than that in genotype C. No additive effect was observed by combining precore and BCP mutations. Hence, HBV genotype and precore/BCP mutations correlate with intrahepatic expression of viral antigens in vitro.     

Hepatitis B virus genotypes, precore mutations, and basal core promoter mutations in HBV-infected Chinese patients with persistently normal alanine aminotransferase and low serum HBV-DNA levels

Hepatitis B virus (HBV) genotype and precore and basal core promoter (BCP) mutants in the patients with persistently normal alanine aminotransferase (ALT) and low serum HBV-DNA levels are unclear. The aim of this study was to determine HBV genotypes, precore and BCP mutations, and their association with chronic hepatitis and liver fibrosis in HBV-infected patients with persistently normal ALT, and low serum HBV-DNA levels in northeast China. Patients (n = 89) with normal ALT and serum HBV-DNA levels below 20000 IU/mL but detectable with real-time PCR were included in this study. HBV genotypes were determined by real-time PCR. The precore and BCP mutations were detected by sequencing. All the patients had biopsy results. Of the 89 patients, 11 (12.4%) were genotype B and 78 (87.6%) were genotype C. The most common mutations were G1896A (23.6%), G1764A (9.0%), and A1762T (6.7%). The prevalence of precore mutation was significantly higher in genotype B patients than in genotype C patients (54.5% vs. 19.2%, p < 0.01). There was no significant difference in the prevalence of BCP mutations between genotype B and genotype C (18.2% vs. 10.2%). Multivariate analysis showed that old age (> 40 years) and BCP mutations were independent predictors of liver necroinflammation and fibrosis. Thus, BCP mutations may be associated with liver necroinflammation and fibrosis in patients with persistently normal ALT and low serum HBV-DNA levels in northeast China.     

乙型肝炎病毒前C区和BCP区突变及基因型对HBeAg表达的影响

研究乙型肝炎病毒前C区和BCP区突变及基因型对HBeAg表达的影响。分别用基因芯片和基因测序的方法检验HBV DNA阳性的乙型肝炎病毒前C区和BCP区突变及基因型,应用时间分辨免疫荧光法检测HBeAg含量,按照有无HBV前C区1896、BCP区1762、1764双突变、基因型等指标进行分组分析。无前C区1896和BCP区1762/1764双突变组、单纯1762、1764双突变和1896突变组以及1896、1762、1764联合突变组之间相互比较,HBeAg含量相差显著,F=6.47,P〈0.01;B、C基因型间HBeAg含量相比,相差无显著性,t=0.1394,P〉0.05。乙型肝炎病毒前C区和BCP区突变能显著影响HBeAg量的表达,从而导致乙型肝炎病毒致病能力的变化。     

Association of core promoter/precore mutations and viral load in e antigen-negative chronic hepatitis B patients

Apart from core promoter A1762T/G1764A and precore G1896A mutations, other hepatitis B virus (HBV) mutants are detected in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). The aim of this study was to determine the effects of those mutants on clinical manifestation and viral loads of genotypes B and C HBV. Seventy-nine HBeAg-negative CHB patients with hepatitis flare were enrolled in this study and their HBV precore/core region were sequenced. Serial biochemical profiles and viral loads were assessed and compared. Fifty-three patients (67%) were infected by genotype B HBV and 26 (33%) were infected by genotype C HBV. The clinical manifestation and HBV viral loads were comparable between the two groups. However, genotype B was significantly associated with precore G1896A mutation (92.5%), and more mutations within nucleotide 1809-1817 were detected in patients infected by genotype B as compared with those infected by genotype C (18.9%vs 3.8%). Most of the cases had mutations at the -2, -3 or -5 position from the precore AUG initiation codon. Triple core promoter mutations T1753C/A1762T/G1764A [corrected] appeared to be linked to genotype C rather than genotype B HBV (19.2%vs 1.9%; P = 0.013). In multivariate analysis, the presence of either triple core promoter 1753/1762/1764 mutation or nucleotide 1809-1817 mutation was the only factor associated with lower HBV viral load (<70 Meq/mL) (odds ratio = 9.01; 95% CI 1.11-71.43; P = 0.04). In conclusion, minor HBV variants with mutations in the core promoter and precore region were detectable in genotypes B and C. Such HBV variants are genotype specific and related to viraemia levels.     

Genomic change in hepatitis B virus associated with development of hepatocellular carcinoma

AIM: To determine the genomic changes in hepatitis B virus (HBV) and evaluate their role in the development of hepatocellular carcinoma (HCC) in patients chronically infected with genotype C HBV.METHODS: Two hundred and forty chronic hepatitis B (CHB) patients were subjected and followed for a median of 105 mo. HCC was diagnosed in accordance with AASLD guidelines. The whole X, S, basal core promoter (BCP), and precore regions of HBV were sequenced using the direct sequencing method.RESULTS: All of the subjects were infected with genotype C HBV. Out of 240 CHB patients, 25 (10%) had C1653T and 33 (14%) had T1753V mutation in X region; 157 (65%) had A1762T/G1764A mutations in BCP region, 50 (21%) had G1896A mutation in precore region and 67 (28%) had pre-S deletions. HCC occurred in 6 patients (3%). The prevalence of T1753V mutation was significantly higher in patients who developed HCC than in those without HCC. The cumulative occurrence rates of HCC were 5% and 19% at 10 and 15 years, respectively, in patients with T1753V mutant, which were significantly higher than 1% and 1% in those with wild type HBV (P < 0.001).CONCLUSION: The presence of T1753V mutation in HBV X-gene significantly increases the risk of HCC development in patients chronically infected with genotype C HBV.     

Epidemiological study of hepatitis B virus genotypes, core promoter and precore mutations of chronic hepatitis B infection in Hong Kong

BACKGROUND/AIMS: We conducted a population study to document the prevalence of hepatitis B virus (HBV) genotypes in Hong Kong. METHODS: HBV genotypes, core promoter (CP) and precore mutations were determined in 776 asymptomatic patients. RESULTS: 92.6% patients had single genotype [B (32.5%), C (62.5%)]. 99.1% of genotype B was subtype Ba. Patients with age <50 years had a lower prevalence of genotype B than patients with age >51 years (32.5% vs. 41%, respectively, P=0.028). Compared to patients with genotype C, patients with genotype B had a higher cumulative rate (P=0.018) and younger age (40.1 vs. 34.2 years, respectively, P=0.018) of HBeAg seroconversion. There were no differences in the HBV DNA levels between patients with genotypes B and C, and with wild-type and mutants of CP and precore regions. By multivariate analysis, patients with genotype C and with CP mutations had higher alanine aminotransferase (ALT) levels. CONCLUSIONS: B and C were the two most common HBV genotypes in Hong Kong. The former had a higher chance of earlier HBeAg seroconversion and lower ALT levels. The prevalence of genotype B was lower in patients with age <50, probably related to influx of immigrants from China since 1949.     

病毒学因素对ALT持续正常的e抗原阴性慢性乙型肝炎病毒感染者肝脏组织学改变的影响

目的 探讨ALT持续正常的HBeAg阴忡慢性HBV感染者病毒学因素与肝脏组织学改变的关系.方法 枪测52例研究对象的HBV DNA水平、基因型、基本核心启动了(BCP)与前C区变异,分析各病毒学因素对肝脏组织学改变的影响.止态分布数据两组间均数比较采用t检验,多组均数比较采用单因素方差分析;非正态分布数据比较采用Mann-Whitney I检验;两样本率的比较用χ2检验及Fisher精确概率法;HBV DNA与肝脏组织学的关系等非参数双变量相关分析采用Spearman相关系数方法;采用受试者T作特征曲线下而积评价HBV DNA水平对肝脏病理改变的诊断价值. 结果 BCP与前C区联合突变组的病毒载量高于非联合突变组[(4.9±1.4)10g10拷贝/ml比(4.1±1.1)log10拷贝/ml,t=2.308,P<0.05];联合突变组32.1%的患者HAI≥4分、14.3%的患者F≥3分.前C区或BCP野毒株的感染者中,HBV DNA与肝脏炎症呈正相关(r值分别为0.626和0.592,P值均<0.01)、与纤维化改变也呈正相关(r值分别为0.730和0.641,P值均<0.01).在尢联合突变的研究对象中,HBV DNA用于预测其F≥3分的肝脏病理改变有显著意义(受试者工作特征曲线下面积为0.905,95%可信区间为0.771～1.039,P<0.05),临界值为4.5 log10拷贝/ml(敏感度1.000,特异度0.778,阿I性预测值为42.9%,阴性预测值为100.0%).基因B型的HBV DNA高于C型[(5.1±1.5)log10拷贝/ml比(4.3±1.0)lOg10拷贝/ml],差异有统计学意义(t= 2.059,P<0.05);但两者在显著肝脏病理改变方面的差异尢统计学意义. 结论 HBV联合突变株的复制能力最强,行且部分联合突变株感染者出现显著肝组织学改变,此类患者有必要接受抗病毒治疗.在前C区或BCP变异野毒株感染者中,HBVDNA与肝脏的炎症、纤维化改变呈正相关,病毒载量用于预测这部分感染者F≥3分的肝脏病理改变有显著意义.     

Molecular analysis of hepatitis B virus isolates in Mexico: Predominant circulation of hepatitis B virus genotype H

AIM:To determine the genotypes in Mexican hepatitis B virus (HBV) isolates and characterize their precore and core promoter mutations.METHODS: Forty-nine HBV isolates of Mexico obtained from sera of 15 hepatitis patients, 6 hemodialysis patients, 20 men seeking HIV testing, and 8 AIDS patients were analyzed. HBV isolates were amplified by PCR,and genotyped by line probe assay (INNO-LiPA HBV Genotyping; INNOGENETICS N V, Ghent, Belgium).HBV genotype confirmation was performed by DNA sequencing part of the sAg region. Precore and core promoter mutation characterization was performed by line probe assay (INNO-LiPA HBV PreCore; INNOGENETICS N.V.; Ghent, Belgium).RESULTS: Overall, HBV genotype H was found in 37(75.5%) out of the 49 isolates studied. HBV genotypes G, A, and D were found in 5 (10.2%), 4 (8.2%), and 3(6.1%) isolates, respectively. HBV genotype H was predominant in isolates from hemodialysis patients (100%),hepatitis patients (80%), and men seeking HIV testing (75%), and accounted for half of infections in AIDS patients (50%). Six (12.2%) out of the 49 HBV isolates showed both wild type and mutant populations at precore codon 28. These mixed wild type and precore murant populations were observed in one HBV genotype A isolate and in all HBV genotype G isolates. A dual variant core promoter mutation was observed in 1 (2%) of the isolates, which was genotype H.CONCLUSION: HBV genotype H is highly predominant in HBV isolates of Mexico followed by genotypes G, A and D. A low frequency of precore and core promoter mutations is observed in HBV Mexican isolates.     

The clinical implications of hepatitis B virus genotype: Recent advances

Outcomes of chronic hepatitis B virus (HBV) infection are heterogeneous. Estimates of annual incidence of cirrhosis and hepatocellular carcinoma (HCC) are 2-10% and 1-3%, respectively. Several viral factors, including HBV genotype, viral load and specific viral mutations, have been associated with disease progression. Among these, HBV genotype is not only predictive of clinical outcomes but has also been associated with response to interferon treatment. Currently, at least 10 HBV genotypes and several subtypes have been identified; they have distinct geographic distribution. Acute infection with genotypes A and D results in higher rates of chronicity than genotypes B and C. Compared to genotype A and B cases, patients with genotypes C and D have lower rates of spontaneous hepatitis B e antigen (HBeAg) seroconversion; when this occurs, it tends to be delayed. HBV genotype C has a higher frequency of basal core promoter (BCP) A1762T/G1764A mutation, pre-S deletion and is associated with higher viral load than genotype B. Similarly, genotype D has a higher prevalence of BCP A1762T/G1764A mutation than genotype A. These observations suggest important pathogenic differences between HBV genotypes. These may contribute to more severe liver disease, including cirrhosis and HCC with genotypes C and D HBV infection. In addition, genotype A and B patients have better responses to interferon-based therapy than genotypes C and D, but there are few consistent differences for direct HBV antivirals. In conclusion, genotyping of chronic HBV infections can help practicing physicians identify those at risk of disease progression and determine optimal anti-viral therapy.