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PubMed2001

Differential interactions between GSTM1 and NAT2 genotypes on aromatic DNA adduct level and HPRT mutant frequency in lung cancer patients and population controls.

We have studied the influence of GSTM1 and NAT2 genotypes on aromatic DNA adduct level (AL) and HPRT mutant frequency (MF) in smokers with newly diagnosed lung cancer and matched population controls. AL was analyzed in relation to genotypes in 170 cases and 144 controls (113 current/recent smokers and 201 former/never smokers), and MF in 157 cases and 152 controls (155 ever smokers and 154 never smokers). Both genotypes exhibited the a priori expected effects on AL and MF among controls only, especially among smoking controls [significantly lower pack-years (a pack-year is defined as 1 pack of cigarettes/day for 1 year) than among cases]. Among the 42 currently smoking controls, the NAT2 slow genotype [odds ratio (OR), 7.5; 95% confidence interval (CI), 1.5-38.4], in particular in combination with the GSTM1 null genotype (OR, 19.3, 95% CI, 1.1-338.6 for null/slow versus positive/rapid) was strongly associated with high AL. The null/slow combination was also significantly associated with high MF among ever smokers (cases and controls pooled) with lower pack-years (OR, 3.7; 95% CI, 1.3-10.7 versus all of the other genotypes; OR, 5.1; 95% CI, 1.2-22.4 versus positive/rapid). In contrast, an antagonistic gene-gene interaction was seen among smoking cases for both AL and MF. Only currently smoking cases with the combined GSTM1 null and NAT2 rapid genotype showed a positive correlation between InAL and InMF (r, 0.64; P = 0.1), and an increase of AL with both age and daily cigarette use. This genotype combination was also associated with high MF among ever-smoking cases (OR, 4.0; 95% CI, 0.9-17.7 versus positive/rapid). There was a significant interaction between NAT2 genotype and pack-years of smoking among cases, so that the rapid genotype was associated with high MF among ever-smoking cases diagnosed at higher pack-years, whereas the slow genotype was associated with high MF at lower pack-years. These findings suggest that the influence of NAT2 genotype on AL and MF and its interaction with GSTM1 genotype may be dose dependent. The NAT2 slow genotype, in particular when combined with the GSTM1 null genotype, may confer increased susceptibility to adduct formation, gene mutation, and lung cancer when the smoking dose is low.

Adult↗

PubMed2001

[Characterization and distribution of hepatitis B virus genotypes and subtypes in 4 provinces of China].

OBJECTIVE: To determine the distribution and genetic relationship of hepatitis B virus (HBV) genotypes and subtypes. METHODS: HBV genotypes and subtypes were determined by PCR and DNA sequencing among 280 chronic HBV carriers in 25 counties of 4 provinces (Hunan, Guangxi, Henan and Hebei) in China. RESULTS: Genotype B, C and D were detected in these regions. Genotypes C and B were the majority genotypes of HBV with 190 cut of 280 (67.9%) genotype C, 82 (29.3%) genotype B, and 8 (2.9%) genotype D. Adr, adw2, ayr, ayw1, ayw2 and ayw3 subtypes were determined among these carriers. Adr and adw2 subtypes were the leading subtypes of HBV, taking up 64.3% and 31.4%, respectively. Adr subtype was completely encoded by genotype C while majority of adw2 subtype was encoded by genotype B. An average rate nucleotide substitutions of 2.94 was seen among 280 Chinese HBV sequences. The average rate of nucleotide substitutions of genotype B (adw2 subtype) was 5.63 (5.48), but only 1.6 (1.51) for genotype C (adr subtype). CONCLUSION: The results suggested that there were significant differences in geographic distribution of HBV genotypes and subtypes; genotype B, in which mostly consistent with adw2 subtype, was a higher variable than genotype C (adr subtype).

Adolescent↗

PubMed2004

Relationship of genotype rather than race to hepatitis B virus pathogenicity: a study of Japanese and Solomon Islanders.

The aim of this study was to determine the predominant hepatitis B virus (HBV) genotype in the Solomon Islands and determine if there is any racial correlation between genotype and hepatitis B e antigen (HBeAg) production in Japanese and Melanesian individuals. A total of 403 serum samples from 206 Melanesian HBV carriers in the Solomon Islands and 197 Japanese carriers from Fukuoka (n = 106) and Okinawa (n = 91) living in Japan in 2001 were tested. The HBV genotypes of 206 Melanesian subjects were 114 with genotype C (55.3%) and 92 with genotype D (44.7%). The HBV genotypes of 197 Japanese subjects were 74 with genotype B (37.6%) and 123 with genotype C (62.4%). The total HBeAg prevalence of subjects in Fukuoka (36.8%) was significantly higher than that of subjects in Okinawa (14.3%) (P < 0.0001) and subjects in the Solomon Islands (35.0%; P = 0.0014, by the Mantel-Haenszel test). The genotype C prevalences were significantly different, ranging from 24.2% in Okinawa, to 54.4% in the Solomon Islands, to 95.3% in Fukuoka (all P < 0.0001, by chi-square test). The prevalence of HBeAg positivity was significantly higher in Melanesian genotype C subjects (42.0%) than Melanesian genotype D subjects (26.6%) (P = 0.0310). Similarly, the prevalence of HBeAg positivity was significantly higher in Japanese genotype C subjects (36.6%) than Japanese genotype B subjects (9.5%) (P < 0.0001). These findings indicate that that HBV was of genotypes C and D in the Solomon Islands, and that the pathogenesis of HBV-infected patients is related to HBV genotype rather than race.

Adolescent↗

PubMed2004

[Reappraisal of HBV genotypes and clinical significance in Koreans using MALDI-TOF mass spectrometry].

BACKGROUND/AIMS: Recent studies have shown that the genotype of hepatitis B virus (HBV) may correlate with the disease natural history and treatment outcome. However, several of these studies used low sensitivity assays in a small number of patients, and this has precluded an accurate evaluation of Korean HBV genotypes. We analyzed Korean HBV genotypes in a large population by employing a new technology, restriction fragment mass polymorphism (RFMP) using MALDI-TOF mass spectrometry, in a sensitive and specific manner. METHODS: Between February 1995 and December 2003, a total of 475 patients with chronic HBV infection were enrolled. The assay is based on the mass measurement of oligonucleotides having genotypic variations of the S gene. Clinical features including the virologic status and disease progression were also evaluated. RESULTS: The median age of the total patients was 35.5 years. Out of 475 patients, there were 162 (34.1%) inactive carriers, 172 (36.2%) had chronic hepatitis, 77 (16.2%) had liver cirrhosis and 64 (13.5%) had hepatocellular carcinoma (HCC). There were 454 patients (95.6%) with genotype C, 4 patients (0.8%) with genotype A, 16 patients (3.4%) with the mixed A and C genotype [7 patients (1.4%) with A A], and 1 patient (0.2%) with B genotype. Comparing genotype A and C, genotype A patients were all inactive carriers without HCC, whereas genotype C patients included those with chronic hepatitis, liver cirrhosis and HCC. CONCLUSIONS: HBV genotype C is highly prevalent in Korea. Although it is a small percentage, genotype A also exists and it seems to take a more benign clinical course than genotype C. Further studies are necessitated to assess the relationship between HBV genotypes and the various aspects of the diseases' clinical course.

Adolescent↗

PubMed2004

[Distribution of hepatitis B virus genotype among population of Dong, Miao minority and Han in Guizhou].

OBJECTIVE: To study the distribution of hepatitis B virus (HBV) genotype in population of Dong, Miao minority and Han in Guizhou. METHODS: S region nucleotides were compared in 127 strains whole sequence of HBV and three restriction enzymes which can be used for genotyping were found by DNA software analysis system. The partial gene fragment of HBV S region was amplified by nested polymerase chain reaction (nPCR). The products were digested with Mbo I, BstN I or BsmA I and subjected to electrophoresis on agarose gel, respectively. The patterns of restriction fragment length polymorphism (RFLP) were analysed. The genotypes were determined by nPCR-RFLP in 166 asymptomatic HBV carriers (ASC), including 48 Dong minority, 52 Miao minority and 66 Han subjects. Some of the ASC were also analysed by direct sequencing of PCR products. RESULTS: The nPCR-RFLP method was simple and accurate. Of the 166 ASC, 138 (83.13%) were genotype B, and 28 (16.87%) were genotype C. Of the 48 Dong minority subjects, 47 (97.2%) were genotype B and 1 (2.08%) was type C. Of the 52 Miao minority subjects, 49 (94.23%) were genotype B and 3 (5.77%) were genotype C. Of the 66 Han subjects, 42 (63.64%) were genotype B and 24 (36.36%) were genotype C. There was a statistical significance in the distribution of genotype C between Dong, Miao minority and Han (7.85% vs 36.36% P less than 0.005). CONCLUSION: Genotype B and C exist in Guizhou and genotype B is the major genotype. Genotype C is found more frequently in Han than in Dong and Miao minority.

Adolescent↗

PubMed2005

[Genotyping of hepatitis B virus and its clinical significance in patients with chronic hepatitis B].

OBJECTIVE: To investigate the distribution of hepatitis B virus (HBV) genotypes in Guangdong and explore its clinical significance. METHODS: Fifty-five patients with chronic active hepatitis (CAH) from Guangdong province were included in this study. HBV surface gene amplified by PCR was analyzed by restriction fragments length polymorphism (RFLP) for HBV genotyping, and the relationship of HBV genotype with clinical, serological and histological data of the patients was analyzed. RESULTS: Twenty-eight out of 55 patients were infected with HBV strains of genotype B (51.0%), 18 with genotype C (32.7%), 4 with genotype D (7.3%), 4 with HBV classified as genotype B+C (7.3%), and 1 (1.8%) with HBV that did not conform to any of the genotypes from A to G. No significant differences in clinical, histological, or serological data of HBV DNA loading were detected between genotypes B and C. But in patients older than 30 years, the genotype C was accompanied by significantly higher HBV DNA loading and serum HBeAg level than genotype B (Fisher's exact test, P=0.002). CONCLUSIONS: HBV genotype B and C are the major genotypes prevalent in Guangdong Province. Genotype C is associated with the longer duration of HBeAg and higher HBV DNA level in patients older than 30 years, suggesting the higher risk of HBV genotype C infection to progress into chronic liver disease.

Adult↗

PubMed2005

[Distribution of hepatitis B virus genotypes in Hubei province and its clinical significance].

OBJECTIVE: To investigate the distribution of hepatitis B virus genotype in Hubei province (China) and its clinical significance. METHODS: Serum samples from 190 HBV DNA positive patients with chronic HBV infection,including 52 asymptomatic HBV carriers (ASC), 56 chronic hepatitis (CH), 32 fulminant hepatic failure (FHF), 22 liver cirrhosis (LC), and 28 hepatocellular carcinoma (HCC) patients were collected and tested for HBV genotypes by type-specific primers. RESULTS: A simple and precise genotyping system based on PCR using type-specific primers was developed for the determination of genotypes of hepatitis B virus (HBV). Of the 190 patients, 140 (73.7%) were genotype B and 42 (22.1%) were genotype C. Genotype B was more prevalent in the FHF and HCC patients than in the ASC patients; the ALT value was significantly higher in genotype B than in genotype C patients. The rate of anti-HBe was significantly higher in genotype B than in genotype C except in the patients of the ASC group. CONCLUSION: The system we used seems to be a useful tool for the molecular diagnosis of HBV infection and for large-scale surveys. Genotype B, genotype C and BC combination exist in Hubei province, and genotype B is the major genotype in this area especially in FHF and HCC patients.

Adult↗

PubMed2004

Prevalence of chronic hepatitis C virus genotypes among patients between 21 to 65 years old in Puerto Rico.

OBJECTIVES: This is the first study done in Puerto Rico to estimate the prevalence of hepatitis C virus (HCV) genotype distribution in patients with chronic infection and to determine the statistical association between the genotype and variables such as age, sex, HCV risk factors, and viral load. METHODS: Chronic HCV infected patients diagnosed with ELISA, RIBA or PCR from 1990 to 2002 who were under follow up with members of the Puerto Rico Gastroenterological Association were asked to participate. Eligible patients were those without evidence of HIV or other viral hepatic infection; had no previous antiviral treatment or if previously treated, therapy ended at least six months prior to their participation in the study; had no history of organ transplant and were willing to participate. All study subjects completed a study questionnaire and had blood samples taken to determine HCV genotype and viral load. RESULTS: 500 patients were recruited. Most of the study subjects were males (68%); 70% were 45 to 65 years old. The principal reported risk factors were: surgeries (75.5%), drug use (46.8%), sexual relationships with intravenous/intranasal drug users (30.3%), blood transfusions (30.2%), multiple sex partners (28.9%), tattoos (22.0%), needle accidents (12.7%), and sexual relationships with an HCV infected partner (9.0%). Most patients had multiple risks factors for infection, only 3.4% (17/500) reported a single risk factor whereas 2.0% (10/500) reported none. 33% of the patients were previously treated (non-responders or relapsers) while 67% were naive. In general, 82% of the HCV patients had genotype 1, while 18% had non-1 genotypes. Among genotype 1 subtypes, genotype la (39.8 %) was more common than 1b (27%). The most common non-1 genotype was genotype 2 of which 2b represented 9.8% of the study population. Similar distribution was observed within the categories of the HCV risk factors, with the exception of those who reported sex with an infected partner (p=0.018), sex with multiple sexual partners (p=0.049) and IVDU (p=0.006). For patients in which the viral load was 2 million IU/ml or less, the genotype la (41%) predominates, followed by 1b (29%) and 1a/1b (9%); patients with viral load was greater than 2 million IU/ml, the genotypes distribution was 1a (38%), 1b (24%), and 2b (12%). After adjusting by type of patients (naive and treated), age and gender, no significant association (p<0.05) were found between two-categories of genotype (1 vs. non-1) and HCV risk factors. CONCLUSION: This cross-sectional epidemiological study demonstrated that the most frequent genotype found in Puerto Rican HCV infected patients is genotype 1. The principal risk factors associated in our population were: surgeries, drug use, blood transfusions, sexual relationships with IVDU, and multiple sex partners. The statistical evidence showed that the genotype distribution is not affected by the HCV risk factor, after adjusting by type of patients (naive and treated), age, gender or geographical area.

Adult↗

PubMed1998

[Genotypes of hepatitis C virus: their relationship with risk factors, the severity of liver disease, and the serologic response].

BACKGROUND: The objective of our study was to ascertain the prevalence of different HCV genotypes between the hepatitis C patients in the health area of Monforte de Lemos, Spain, as well as the possible influence of risk factors on their distribution and their relation with hepatic disease and with the serologic response. PATIENTS AND METHODS: We have studied 128 patients with hepatitis C. Of these, 41 were intravenous drug users (IVDU), 19 had received transfusions, 7 were hemodialyzed and in 61 the risk factors were unknown. Antibodies against HCV were detected by second-generation enzyme immunoassay (EIA) and confirmed by immunoblot. RNA-HCV presence was studied by reverse transcription-PCR (RT-PCR), and a reverse hybridization test of the amplifications was used for the genotyping. RESULTS: Hepatitis C genotypes 1b (46.1 [8.6%]), 1a (23.4 [7.3%]) and 3a (13.3 [5.9%]) were the most frequently encountered genotype. Genotype 1a (48.8 [15.3%]) was the most prevalent genotypes in IVDU patients, while 1b was the most frequent in patients of unknown risk factors (62.3 [12.1%]). Alanine-aminotransferase (ALT) was elevated in 66.6 (17.7%) of patients with genotype 1a, in 87.5 (8.6%) of patients with genotype 1b (p = 0.0367) and in 94.1 (11.2%) of patients with genotype 3a (p = 0.0347). Subtype 1b was present in 6 of 7 cases of cirrhosis (85.7%) and in 7 of 12 cases of active chronic hepatitis (58.3%). No significant statistical differences were observed between the genotypes and the specific IgM response against core antigen of HCV, neither we observed differences in the serologic response against C1, C2, NS3 and NS4 peptides. CONCLUSIONS: Hepatitis C genotypes 1a and 3a were the most prevalent genotypes between IVDU patients while genotype 1b was the most frequent between non-IVDU patients. Genotype 1b was associated to severe liver disease. Percentage of positivity or the reactivity against HCV peptides was independent of the genotype encountered in the patient.

Genotype↗

PubMed2026

Pedigree-assisted genotype imputation enables cost-effective genomic prediction in Penaeus vannamei.

Genomic selection in Penaeus vannamei has long been constrained by the high cost of dense genotyping. To address this limitation, we evaluated genotype imputation from a low-density 1 K panel to a medium-density 55 K panel of the "Yellow Sea Array No. 1" and examined its impact on genomic prediction for harvest body weight in P. vannamei. A four-generation pedigree including 30 great-grandparents, 39 grandparents, 100 parents, and 608 offspring was genotyped using the 55 K panel. A two-step experimental design was implemented to (i) assess the performance of different imputation algorithms under reference population scenarios with varying proportions of siblings, and (ii) compare six alternative reference population structures incorporating parents, ancestors, and siblings. Genotype imputation using the pedigree-based method FImpute v3.0 consistently achieved higher accuracy than the population-based method Beagle v5.5. Using this pedigree-assisted approach, imputation accuracy increased from 0.73 when only parental genotypes were used to 0.84 with the inclusion of 10% siblings, and subsequently plateaued at 0.87-0.90 when sibling representation reached 20%. Across the six reference population structures, imputation accuracy was primarily driven by the availability of parental genotypes, ranging from 0.50 to 0.56 in the absence of parents to 0.88-0.89 when both parents and ancestral generations were included. Accuracy remained high when both parents were available (0.84-0.87 with siblings; 0.73 without siblings) but declined substantially when only one parent was genotyped (0.65-0.68). Imputation accuracy was positively associated with both minor allele frequency (MAF) and linkage disequilibrium (max r2LD), with LD exerting the stronger influence. Heritability estimates derived from imputed 55 K genotypes were highly consistent with those obtained from the original 55 K data (0.39 ± 0.14 vs. 0.41 ± 0.14), indicating that genotype imputation did not compromise variance component estimation. In predictive ability analyses, pedigree-based BLUP (PBLUP) achieved higher predictive ability than genomic BLUP (GBLUP) based on the 1 K panel, with predictive abilities of 0.42-0.44 for PBLUP compared with 0.34-0.35 for GBLUP. Using imputed genotypes for genomic prediction further improved predictive ability relative to the true 1 K panel, yielding values ranging from 0.35 to 0.47. Notably, when parental genotypes were included in the reference population, GBLUP based on imputed genotypes surpassed the predictive ability of PBLUP and approached that achieved with the original 55 K genotypes (0.45-0.47). Collectively, these results provide the first empirical evidence that low- to medium-density genotype imputation, combined with pedigree information, can effectively support genomic prediction in P. vannamei. This study establishes a cost-efficient and scalable framework for implementing genomic selection in P. vannamei and provides a practical reference for the application of genomic selection in other aquaculture species with constrained breeding budgets.

Animals↗

PubMed2006

Phylogenetic analysis of the precore/core gene of hepatitis B virus genotypes E and A in West Africa: new subtypes, mixed infections and recombinations.

One hundred and twenty-two new hepatitis B virus (HBV) preC/C sequences and three complete genomes from three major countries in West Africa were analysed. The majority of sequences were of genotype E and the only other genotype found was genotype A. Although for genotype E sequences, the genetic diversity of the preC/C gene was about two to three times higher than that of the preS/S gene, it was still considerably lower than that for genotype A sequences. The HBV/E preC/C gene was related most closely to subgenotype D1 and D2 sequences. Evidence of recombination was found in two strains that were of genotype A in the preS/S gene and of genotype E in the preC/C gene. The genotype A strains from Cameroon, Mali and Nigeria could be divided phylogenetically into three subtypes, A3 and two new subtypes, tentatively designated A4 and A5. Each subtype presented a genetic diversity of 2.19-3.85 % and intersubtype distances of 4.47-5.97 %. Interestingly, one sample from Nigeria showed evidence of a triple recombination of genotypes E/D and A, separated by a genotype G-specific insert of 36 bp. Of 110 patients, 19 (17.3 %) showed a coinfection of genotypes A and E, mostly in human immunodeficiency virus-positive children from Cameroon. Thus, in Cameroon, where both genotypes coexist, 37 % of all individuals tested had mixed infections. The low genetic variability in the preC/C gene of genotype E supports our previous speculation about a relatively short evolutionary history of this genotype, in contrast to the subtype-rich African genotype A strains.

Adult↗

PubMed2004

Hepatitis B virus genotype A and D and clinical outcomes of liver transplantation for HBV-related disease.

Hepatitis B virus (HBV) genotypes have been associated with specific patterns of disease and response to antiviral therapy. We investigated the effect of HBV genotype on HBV recurrence and mortality after liver transplantation (LT). Pretransplant sera of 45 hepatitis B surface antigen (HBsAg) positive adults were submitted for HBV genotyping by a reverse-phase hybridization line probe assay with genotype-specific probes. Data were correlated with clinical outcomes after transplantation. Genotype A (n =15), D (n = 13) and A/D (n = 12) accounted for 89% of all genotypes. Coinfection with two HBV genotypes was encountered in 14 (31.1%) patients. Eighteen patients (40 %) developed HBV recurrence at a median of 10 months posttransplant (range, 1-53) and 10 patients (22 %) died at a median of 24 months (range, 3-63). Genotype D patients were more likely to develop HBV recurrence or die compared with genotype A patients, although this did not reach statistical significance. Dual infection with genotype A/D resulted in mortality similar to that of genotype A but recurrence similar to that of genotype D. Active viral replication at time of transplantation was the only independent factor (P = 0.03) that predicted HBV recurrence. In conclusion, HBV genotype A and D did not have a significant impact on clinical outcomes of LT for HBV-related liver disease in patients of European origin. These data do not support routine HBV genotyping in liver transplantation.

Adolescent↗

PubMedDate not supplied

HCV genotypes in Swedish blood donors as correlated to epidemiology, liver disease and hepatitis C virus antibody profile.

Sixty-two anti-HCV and HCV-RNA positive Swedish blood donors (44 men, 18 women; median age 34 years) were studied. HCV genotypes were correlated to parenteral risk factors, liver morphology, serum alanine aminotransferase (ALAT) levels and HCV antibody profile. Forty percent of the donors were infected with HCV genotype 1a, 10% with 1b, 21% with 2b, and 29% with 3a. Intravenous drug use (IVDU) was more common in donors with genotype 3a than in those with genotype 1a (p = 0.024), and prior blood transfusion more common in genotype 2b than in 3a (p = 0.012). Chronic active hepatitis with and without cirrhosis was found in 38% of donors infected with genotype 2b as compared to 8% of donors infected with 1a (p = 0.034). Forty percent of donors with genotype 1a had normal ALAT at the time of liver biopsy versus 11% with genotype 3a (p = 0.046). Antibodies to C33c and C22-3 were present in nearly all donors whereas reactivity to C100-3 and 5-1-1 was detected more often in donors with genotypes 1a and 1b as compared to donors with genotypes 2b and 3a. In conclusion, genotype 3a was correlated to IVDU or tattooing as parenteral risk factors for the acquisition of HCV infection, and genotype 2b to prior blood transfusion. Donors with genotypes 1a seemed to have less severe liver disease than those infected with genotypes 2b and 3a.

Adult↗

PubMed2004

HCV genotype 4--an emerging threat as a cause of chronic liver disease in Indian (south) patients.

BACKGROUND: Hepatitis C virus (HCV) genotyping is relevant for the delivery of effective antiviral therapy. HCV genotypes are geographically restricted with genotype 4, which is resistant to therapy, traditionally considered to be confined to the Middle East and Africa. We report here on the occurrence of HCV genotype 4 in Indian (South) patients. OBJECTIVES: 1) To highlight the occurrence of HCV genotype 4 in the patient population attending a tertiary care hospital in south India. 2) To ascertain the difference in HCV viral loads and alanine aminotransferase (ALT) values between patients infected with HCV genotype 4 and those infected with the other two most commonly detected genotypes in this patient population viz., HCV genotypes 1 and 3. 3) To assess the genetic relatedness of the Indian strains to Genbank sequences, which we report for the first time. STUDY DESIGN: The study group consisted of 125 HCV infected, untreated patients who had been genotyped using type specific primers. Eight of the nine samples classified as HCV genotype 4 by this technique were subjected to nucleotide sequencing. Viral load estimations were carried out. Information on possible risk factors and ALT values were obtained from hospital records. Statistical analyses were carried out to compare viral loads and ALT values across genotypes. A phylogenetic tree was constructed and the genetic relatedness of the strains was assessed through sequence analysis. RESULTS: HCV genotype 4 was detected in nine of 125 (7.2%) patients. Eight of the nine were subjected to nucleotide sequencing and all strains were confirmed as HCV genotype 4. Six of the eight strains were closely related, with two strains being phylogenetically diverse. CONCLUSIONS: HCV genotype 4 is detected in a significant minority of HCV infected patients in India. This finding should be considered in designing strategies prior to initiation of therapy in Indian patients infected with HCV.

Adult↗

PubMed2003

Hepatitis B virus genotypes and virologic response in 694 patients in phase III studies of adefovir dipivoxil1.

BACKGROUND & AIMS: Hepatitis B virus (HBV) genotype may influence disease progression and antiviral response. We therefore analyzed the frequency and distribution of genotypes in patients from 2 multinational phase III studies of adefovir dipivoxil. Antiviral efficacy of adefovir dipivoxil 10-mg therapy was examined with respect to HBV genotype, hepatitis B e antigen (HBeAg) serostatus, and race. METHODS: HBV genotypes were assigned by phylogenetic analyses of DNA sequences amplified from baseline serum samples (n = 694). RESULTS: Patients from Asia/Oceania were infected predominantly with genotypes B and C, whereas patients from Western European countries were infected predominantly with genotypes A and D. In Mediterranean countries, genotype D was dominant. The most common genotype in North America was C, followed by A, B, and D. Regardless of location, Asian patients were infected predominantly with genotypes B or C, whereas Caucasian patients were infected predominantly with A or D. There were significant differences in the baseline serum HBV-DNA levels of patients infected with different HBV genotypes regardless of HBeAg serostatus. Forty-eight weeks of adefovir dipivoxil 10-mg therapy resulted in potent reductions in serum HBV DNA with no significant differences based on genotype, HBeAg status, or race; similarly, there was no statistical difference in HBeAg seroconversion rates between genotypes in these patients. CONCLUSIONS: HBV genotypes were distributed asymmetrically with respect to race, geography, and HBeAg status. Forty-eight weeks of adefovir dipivoxil therapy resulted in significant decreases in serum HBV-DNA levels in patients regardless of HBV genotype, HBeAg status, or race.

Adenine↗

PubMed1999

Serological detection of hepatitis B virus genotypes by ELISA with monoclonal antibodies to type-specific epitopes in the preS2-region product.

An ELISA was developed for serological determination of the six genotypes of hepatitis B virus (HBV) designated A, B, C, D, E, and F. Monoclonal antibodies were raised against genotype-specific epitopes in the preS2-region product, and labeled with horseradish peroxidase. Hepatitis B surface antigen (HBsAg) in sera was captured by immobilized antibodies against the common determinant, and evaluated for reactivity with genotype-specific monoclonal antibodies labeled with the enzyme. Serological genotyping was in complete accord with genotypes determined by S-gene sequences in a panel of 68 sera containing HBV/HBsAg of different genotypes. Of 514 sera with HBsAg from Japan, 507 (98.6%) were genotyped serologically: genotype A was identified in 24 (4.7%); B in 196 (38.1%); C in 282 (54.9%); D in 2 (0.4%); and F in 3 (0.6%). There were no sera containing HBV of genotype E. Likewise, 425 of 446 (95.3%) sera with HBsAg from Brazil, China, India, Indonesia, Kenya, Korea, Nepal, Papua New Guinea, the Philippines, and Thailand were classified into A (25.6%), B (24.2%), C (33.9%), and D (11.7%) genotypes; there were no sera with HBsAg of genotype E or F among them. Some sera unclassifiable by ELISA revealed mixed infection with HBV of distinct genotypes, or contained HBsAg deprived of genotype-specific epitopes by point mutations. The ELISA would be useful for large-scale surveys, because it allows serological detection of HBV genotypes without sequencing nucleotides.

Amino Acid Sequence↗

PubMed1997

Distribution of hepatitis C virus genotypes in German patients with chronic hepatitis C: correlation with clinical and virological parameters.

BACKGROUND/AIMS: The hepatitis C virus genotypes have been shown to be differently distributed between distinct geographical areas and to be associated with different clinical presentations. In the present study we investigated the distribution of HCV genotypes in 379 German patients with chronic hepatitis C in relation to age, sex, route of infection, liver histology and viremia. METHODS: Typing of HCV was done using restriction fragment length polymorphism analysis as well as a DNA enzyme immunoassay. HCV RNA concentrations were determined by quantitative polymerase chain reaction. Liver biopsies were performed in 187 patients and the histological activity was graded by the Knodell score. RESULTS: Seventy percent were infected with genotype 1 (20% subtype 1a, 80% subtype 1b), 4% with genotype 2 and 26% with genotype 3 (all subtype 3a). Genotype 3a and 1a infection was significantly associated with intravenous drug abuse. In contrast, genotype 1 predominated in patients with post-transfusion hepatitis and infection of unknown origin. A changing relative prevalence of HCV genotypes in relation to age was also observed. Patients with genotype 3 infection showed significantly lower HCV RNA levels and a lower mean histological activity score as compared to patients with genotype 1 and genotype 2. However, using multivariate analysis, only age and mode of transmission but not histological activitiy score were shown to be independent variables. CONCLUSIONS: Our study confirms previous reports from other countries that HCV variants can be classified into a relatively small number of discrete genotypes, and that the subtype 1b clearly predominates. However, we found evidence that there is a changing relative prevalence of HCV genotypes in relation to age, and that the mode of transmission is reflected in the predominance of certain genotypes.

Adolescent↗

PubMed2004

Hepatitis B genotypes correlate with tumor recurrence after curative resection of hepatocellular carcinoma.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC), compared with genotype B. This study aims to investigate whether HBV genotypes influence the clinicopathologic features and long-term prognosis of patients after curative resection of HCC. METHODS: Stored serum samples from 62 patients with HBV-related HCC were tested for HBV genotype using a molecular method. RESULTS: Sixty of 62 patients (96.8%) undergoing curative resection of HCC were infected with genotype B or C. Concomitant cirrhosis was encountered more frequently in patients with genotype C. During a mean follow-up period of 26.3 +/- 9.8 months, patients with genotype B had a lower overall tumor recurrence rate than those with genotype C (22% vs. 46%; P = 0.04). Stepwise multiple Cox proportional hazards regression analysis showed that multiplicity of tumor (hazard ratio, 6.84; 95% confidence interval [CI], 1.45-32.2; P = 0.02) was associated with tumor recurrence, whereas genotype C and age were associated with borderline significance (P = 0.06). Stratified analysis showed that genotype C was still associated with tumor recurrence in cirrhotic patients with borderline significance by univariate analysis (hazard ratio, 3.8; 95% CI, 0.84-17.6; P = 0.07). However, cumulative 2-year survival rates were similar between patients with genotype B and C (92% vs. 85%; P = 0.23). CONCLUSIONS: Our data suggest that patients with HCC with genotype C have a greater tumor recurrence rate after curative resection of HCC compared with those with genotype B. Prolonged follow-up is needed to clarify the impact of HBV genotype on postoperative outcome.

Adult↗