Genetic variability in the precore and core promoter regions of hepatitis B virus strains in Karachi

Abstract

BackgroundHepatitis B virus (HBV) genotypes have distinct geographic distribution. Moreover, much genetic variability has been described in the precore (PC) and basal core promoter (BCP) regions of the HBV genome. The local prevalence of HBV genotypes and mutations has not been well studied. The aim of the present study is to determine the prevalence of HBV genotypes and mutations in the PC and BCP region in HBV strains in Karachi.MethodsA total of 109 chronic hepatitis B patients with detectable HBV DNA by a PCR assay were enrolled in the study. Sera were tested for HBeAg, anti-HBe antibody and liver profile. HBV genotypes and mutations in the PC and BCP regions were detected by INNO-LiPA line-probe assays.ResultsOf the 109 patients investigated, 38 (35%) were HBeAg positive while 71 (65%) were HBeAg negative. Genotype D was present in 100% of the patients. Two patients had co-infection with genotype A. There was no significant difference in the baseline characteristics, mean ALT levels, and presence of clinical cirrhosis in patients with HBeAg positive or negative strains with or without PC and BCP mutations. Of the 38 HBeAg positive patients, 9 (24%) had PC and BCP mutations. In the HBeAg negative patient group, mutations were detected in 44 (62%) of the strains investigated. More than one mutation was common, seen in 26 (37%) patients with HBeAg negative disease and 6 (16%) patients with HBeAg positive disease. Twelve (17%) HBeAg negative patients had dual T1762 and A1764 mutations. None of the HBeAg positive patients had T1762 mutation. Mutations were undetectable in 27 (38%) of patients with HBeAg negative disease.ConclusionOur study shows that type D is the main HBV genotype in Karachi, Pakistan. Significant numbers of patients infected with this genotype have PC and BCP variants. Mutations at more than one site are common. Patients harboring these mutants do not differ significantly in their clinical presentation from patients having wild type infection.

Co-treatment with pegylated interferon alfa-2a and entecavir for hepatitis D: A randomized trial

“…Interferon based therapy is known to induce HBsAg seroconversion and it is usually associated with low pretreatment HBsAg levels [16] . We did not check for genotypes of HBV and HDV for this study as it is already known that the genotype of hepatitis D is 1 [17] and of hepatitis B is D in our region [18] . We followed our patients for six months post treatment.…”

Hepatitis B virus genotypes, subgenotypes, precore, and basal core promoter mutations in the two largest provinces of Pakistan

“…reported that genotype C is the most predominant, while genotype A was predominant in Sind Province, genotype C in North West Frontier Province 11 and genotypes B and C in Punjab. In another study by Abbas et al ., it was reported that D is the predominant genotype in Karachi, the largest city in Pakistan and also the capital of Sind Province 12 . None of the abovementioned studies have performed whole genome or partial genome sequencing of HBV.…”

Characterization of Basal Core Promoter/Precore Gene Mutations in Chronically Infected Patients with Hepatitis B Virus Genotype D in Mersin Province, Turkey

“…Ancak bizim çalışmamızda HBeAg pozitif hastaların %20'sinde prekor mutasyonu tespit edilmesine rağmen HBeAg kaybolmamış-tır. Benzer sonuçlar başka araştırmacılar tarafından da bildirilmiştir 17,19,23,28 . PC G1896A mutasyonu ile HBeAg pozitifl iği arasındaki bu uyumsuzluk, HBeAg serokonversiyon sü-recinde vahşi tip HBeAg salgılayan virus popülasyonları ile karışık enfeksiyon oluşumu ile açıklanabilmekle birlikte, enfeksiyonun seyri sırasında HBeAg'nin temizlenmesi beklenmektedir.…”