Hepatitis B Virus Genotypes and Pre-core and Core Genes Mutations in a Sample of Iraqi Patients with Chronic Hepatitis B Infection

Abstract

Background: Genomic studies of hepatitis B virus (HBV) diversity are becoming increasingly significant to understand how HBV mutations interact with a wide spectrum of clinical and pathological disorders. Objective: This study focused on identifying HBV genotypes and determining the status of pre-core (PC) and core promoter (CP) mutants. Methods: Nested polymerase chain reaction was used to identify the viral genotypes of 100 patients with chronic HBV infection. Only 30 samples out of 100 were selected to determine the prevalence of mutations in the PC and CP by Sanger sequencing. Results: Over 95% of the samples had only D genotype and mixed genotypes 5% (B+C+D) in chronic hepatitis B (CHB) patients. G1898A, G1901A, G1910A and G1915A mutations in PC gene were found in total 15 out of 30 (50%) samples, which were distributed in the following proportions: 12 out of 25 (48%) in patients with hepatitis B e antigen (HBeAg) -ve, 8 samples with mutants at G1898A, G1901A, G1910A and G1915A (four mutations), 4 samples with mutants at G1898A, G 1901A and G1910A (three mutations). In addition, 3 out of 5 (60%) in patients with HBeAg +ve, while no type of any mutation was detected in the core gene in patients with chronic hepatitis type B. Conclusion: The genotype D was predominantly prevalent among HBV in CHB patients with 95% and with 5% in mixed genotypes (B+C+D), while genotype B and C were relatively less prevalent among CHB patients than genotype D. The mutations were found in the PC gene at nucleotides G1898A, G1901A, G1910A and G1915A, while no type of mutation was detected in the core gene. Keywords: Genotypes, pre-core mutation, core mutation, HBV Citation: Hussain HT, Al-Shuwaikh AM, Ahmed AM. Hepatitis B virus genotypes and pre-core and core genes mutations in a sample of Iraqi patients with chronic hepatitis B Infection. Iraqi JMS. 2022; 20(2): 217-225. doi: 10.22578/IJMS.20.2.8

A Survey of HBV Core/Pre-Core Mutations in Iraqi Patients with Chronic Hepatitis

“…The results revealed 21 nucleic acid variants corresponding to five amino acid substitutions (103G>V, 109I>A, 109I>M, 109I>V, and 110S>A) in the core protein's amino acid sequence. Hussain et al (24), in a study in Iraq, identified Pre-Core/Core mutations in 50% of CHB patients, regardless of the HBeAg status, and most of their samples belonged to genotype D. In a study from Iran, Farshadpour et al (25) detected Pre-Core/Core mutations in 11 out of 19 diabetic patients carrying HBV DNA, most of which were also genotype D (subtypes D1 and D3). In terms of more frequent mutations (such as alterations in amino acid residues 109 and 143 in the Pre-Core/Core protein), our findings are similar to those of Farshadpour et al In addition to genotype D, Pre-Core/Core mutations are also found in other HBV genotypes as well (26).…”

“…However, the sequences of the C gene-based G genotype have been less frequently deposited in the NCBI database. It appears that genotype D is the main HBV genotype in Iraq (24,25,31). There are some reports suggesting a role for HBV genotype in HCC development.…”

Full-Length Genome Sequencing and Analysis of Hepatitis B Viruses Isolated from Iraqi Patients

“…Databases of HBV sequences such as NCBI virus and Hepatitis B virus (HBV) databases frequently consist of whole genome sequences of individual viral isolates obtained from Sanger sequencing. In Iraq, studies were conducted to determine the viral genotypes using molecular techniques of different genes or regions of HBV genomes [ 9 , 10 ]. Nonetheless, there are no reports on the whole genome sequence of HBV isolated from Iraqi patients.…”