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Mutational Pattern (mutational + pattern)

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Medical Sciences	54%

Selected Abstracts

Molecular evolutionary analysis and mutational pattern of full-length genomes of hepatitis B virus isolated from Belgian patients with different clinical manifestations

JOURNAL OF MEDICAL VIROLOGY, Issue 3 2010
Mahmoud Reza Pourkarim
Abstract Molecular evolutionary patterns of 62 HBV full-length genomes obtained from Belgian patients were characterized. Phylogenetic analysis revealed diverse HBV subgenotypes including A2 and A6 (46.8%), D1,D4 (38.8%), E (9.7%), C1 (1.6%), and B2 (1.6%). The study population consisted of patients with different ethnic origin (Caucasian, Turkish, Asian, Arab, and African). One HBV D/C recombinant isolate was identified, which encoded subtype adw2. An HBV subgenotype D4 with an aberrant subtype ayw4 was detected. Although none of the genotypes was associated with a specific disease outcome, several nucleotide substitutions, deletions and insertions were observed within the HBV preS1/S and X genes, particularly among patients with active chronic hepatitis B infection and patients with cirrhosis. Within the immunological domain of the HBsAg gene, the most frequent substitutions were sT125M and sT118A. High rates of precore and basal core promoter mutations were detected in patients infected with genotype D of HBV. Almost half of the patients who received lamivudine therapy for at least 1 year had HBV variants associated with lamivudine drug resistance. In conclusion, the most common HBV genotypes in West Europe (A and D) also prevail in Belgium. The highest degree of genetic diversity was detected in HBV genotype D. In addition, this study reveals the circulation of exotic HBV genotypes B, C, and E in Belgium. J. Med. Virol. 82:379,389, 2010. © 2010 Wiley-Liss, Inc. [source]

Effect of HIV co-infection on mutation patterns of HBV in patients with lamivudine-resistant chronic hepatitis B,,§

JOURNAL OF MEDICAL VIROLOGY, Issue 7 2009
Fabio Iacomi
Abstract A retrospective review was performed comparing lamivudine-resistance mutation patterns between patients infected with hepatitis B virus (HBV) with or without human immunodeficiency virus (HIV) co-infection. Medical records that included a genotypic test of patients infected with HBV and treated with lamivudine as the only anti-HBV drug were reviewed. Pol gene mutations were assessed by direct sequencing of the reverse transcriptase fragment 125,213 aa. Eighty-nine patients infected with HBV (29 co-infected with HIV) with rtM204V or rtM204I mutations were included. Multiple mutations associated with the YMDD motif were observed in 33 (55%) of 60 patients infected with HBV only and in 28 (96.6%) of patients co-infected with HIV/HBV. In this latter group, the prevalence of the rtV173L,+,rtL180M,+,rtM204V triple mutation was 31% versus a prevalence of 3.4% observed among patients infected with HBV only. All patients with the triple mutational pattern showed sE164D,+,sI195M changes in the envelope gene. Multivariate analysis demonstrated that HIV co-infection (adjusted OR 11.2, 95% CI 2.0,61.0) and HBV genotype A (adjusted OR 7.2, 95% CI 1.5,34.8) were the only independent variables associated with the chance of harboring rtM204V. Patients with HBV genotype A or HIV co-infection were more likely to harbor the rtM204V mutation. Patients co-infected with HIV showed multiple mutations more frequently, including the triple mutation that may elicit a vaccine escape phenotype. Among patients co-infected with HIV/HBV, strict HBV DNA monitoring is essential to detect treatment failure and adapt therapy to avoid limitations of future therapeutic options or the emergence of a public health threat. J. Med. Virol. 81:1151,1156, 2009. © 2009 Wiley-Liss, Inc. [source]

Prevalence of the mutational pattern E44D/A and/or V118I in the reverse transcriptase (RT) gene of HIV-1 in relation to treatment with nucleoside analogue RT inhibitors

JOURNAL OF MEDICAL VIROLOGY, Issue 3 2002
Brigitte Montes
Abstract It has been reported that a new pattern of mutations, E44D/A and/or V118I, in the reverse transcriptase (RT) gene of HIV-1 confers a moderate level of resistance to lamivudine in the absence of the M184V mutation. The prevalence of this mutational pattern was studied in HIV-1 isolates obtained from 280 patients. These mutations were not identified in the RT sequences from 23 antiretroviral-naive patients but were detected in 82 (31.9%) of the 257 RT sequences obtained from nucleoside reverse transcriptase inhibitors (NRTI)-experienced patients. Mutation at codon 44 was identified in 41 patients (7 mutations E44A and 34 mutations E44D), mutation V118I was identified in 73 patients and a combination of mutations at codons 44 and 118 was found in 32 patients. Multivariate analysis showed an association between the E44D/A and/or V118I mutational pattern and the RT mutations D67N, T69D, L210W, and T215Y/F. No relationship was observed between this mutational pattern and the lamivudine-specific resistance mutation M184V. The prevalence of these mutations increased significantly with the number of drug regimens experienced and a prevalence of 42.4% was observed in patients who had received ,,4 antiretroviral regimens. A relationship was found between the E44D/A and/or V118I mutational pattern and experience with didanosine or stavudine but not with lamivudine. The results suggest that the development of the E44D/A and/or V118I mutational pattern is frequent in patients treated with NRTIs. Thymidine analogues and didanosine, but not lamivudine, could promote the development of these mutations. J. Med. Virol. 66:299-303, 2002. © 2002 Wiley-Liss, Inc. [source]

Virological analysis, genotypes and mutational patterns of the HBV precore/core gene in HBV/HCV-related hepatocellular carcinoma

JOURNAL OF VIRAL HEPATITIS, Issue 9 2006
M. S. De Mitri
Summary., We investigated the replicative profile of hepatitis B (HBV) and hepatitis C (HCV) viruses and the mutational pattern of the HBV precore/core (pre-C/C) domain in hepatocellular carcinoma (HCC). Thirty-eight consecutive patients with HCC were included in the study , 18 of them with HBV/HCV co-infection and 20 with HBV single infection. Twenty-three additional patients with co-infection, without HCC were recruited as the control group. Replication activity was evaluated by detecting and quantitating both HBV and HCV genomes. The HBV pre-C/C region, encompassing the pregenome encapsidation signal involved in viral replication, was analysed by direct sequencing. HBV viraemia levels were significantly lower (P = 0.04) in patients with co-infection in comparison with single-infected HCC, whereas two different HBV viraemia profiles were detected in co-infection with or without circulating HCV. HBV genotype D was prevalent in the three groups and HCV genotype 1b was found to be the infecting strain in all patients. Lower variability in the pre-C/C region was found in co-infection in comparison with HBV single infection (P = 0.0004). A synonymous T1936C mutation was found in all co-infected HCC cases not related to the presence or absence of circulating HCV, and a hypermutated pre-C strain, characterized by the same mutational pattern, was identified in three HCC cases. The mutational pattern of the pre-C/C region was closely related to HBV replication efficiency, and specific HBV mutations selectively associated with HCV co-infection could be linked with accelerated HBV/HCV-related disease progression. [source]

Major differences in bleeding symptoms between factor VII deficiency and hemophilia B

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2009
F. BERNARDI
Summary.,Background:,The autosomally-inherited factor VII (FVII) deficiency and X-linked hemophilia B offer an attractive model to investigate whether reduced levels of FVII and FIX, acting in the initiation and amplification of coagulation respectively, influence hemostasis to a different extent in relation to age and bleeding site. Methods:,Hemophilia B patients (n = 296) and FVII-deficient males (n = 109) were compared for FVII/FIX clotting activity, F7/F9 genotypes and clinical phenotypes in a retrospective, multi-centre, cohort study. Results:,Major clinical differences between diseases were observed. Bleeding occurred earlier in hemophilia B (median age 2.0 years, IR 0.9,5.0) than in FVII deficiency (5.2 years, IR 1.9,15.5) and the bleeding-free survival in FVII deficiency was similar to that observed in ,mild' hemophilia B (P = 0.96). The most frequent disease-presenting symptoms in hemophilia B (hematomas and oral bleeding) differed from those in FVII deficiency (epistaxis and central nervous system bleeding). Differences were confirmed by analysis of FVII-deficient women. Conclusions:,Our data support the notion that low FVII levels sustain hemostasis better than similarly reduced FIX levels. On the other hand, minute amounts of FVII, differently to FIX, are needed to prevent fatal bleeding, as indicated by the rarity of null mutations and the associated life-threatening symptoms in FVII deficiency, which contributes towards shaping clinical differences between diseases in the lowest factor level range. Differences between diseases are only partially explained by mutational patterns and could pertain to the specific roles of FVII and FIX in coagulation phases and to vascular bed-specific components. [source]

Differences of YMDD mutational patterns, precore/core promoter mutations, serum HBV DNA levels in lamivudine-resistant hepatitis B genotypes B and C

JOURNAL OF VIRAL HEPATITIS, Issue 11 2007
X. P. Pan
Summary., The aims of this study were to investigate the viral differences among lamivudine-resistant hepatitis B virus (HBV) genotypes B and C in vivo. Fifty-three patients carrying lamivudine-resistant HBV were enrolled in this study. HBV genotypes, Levels of alanine aminotransferase (ALT), HBV DNA levels were monitored during therapy. The polymerase and precore/core promoter genes were amplified by polymerase chain reaction and their products were sequenced directly. Among 53 patients resistant HBV genotypes B and C accounted for 41.50% and 58.50%, respectively. The occurrence of reverse transcriptase rt204I mutants was lower in genotype B (36.36%) than that in genotype C (87.10%), whereas rt204V mutants was higher in genotype B (63.64%) than that in genotype C (12.90%). The occurrence of precore mutation (nt1896A) was higher in genotype B (77.27%) than that in genotype C (32.26%). Serum HBV DNA levels after emergence of lamivudine resistance were higher in genotype C (7.71 ± 0.80 Log copies/mL) compared with genotype B (6.97 ± 0.77 Log copies/mL). Multivariate analysis identified pretreatment HBV DNA levels, HBeAg status and HBV genotype as independent factors associated with a shorter time to lamivudine resistance(P = 0.035, P = 0.006 and P = 0.001, respectively). Multivariate analysis showed that HBV genotype (P = 0.004) and pretreatment ALT levels (P = 0.01) was independently associated with YMDD mutational patterns. The results showed that the YMDD mutational patterns, precore mutation and serum HBV DNA levels differ between lamivudine-resistant HBV genotypes B and C in vivo. It is valuable for treatment of lamivudine-resistant HBV in clinic. [source]