title: Prevalence of mutations within major hydrophilic region of hepatitis B virus and their correlation with genotypes among chronically infected patients in Egypt.
abstract: OBJECTIVE
  Mutations within the major hydrophilic region (MHR) of the hepatitis B surface antigen (HBsAg) have been reported in relation to viral persistence by evasion from vaccine and immunotherapy, severity of liver disease and lack of detection by commercial kits. The aim of this study was to elucidate the circulation of hepatitis B virus (HBV) genotypes, subgenotypes and serotypes in Egypt, with recognition of the pattern and prevalence of MHR mutations possibly occurring during the course of the disease.
  
  
  METHODS
  Eighty-eight samples from patients with chronic HBV infection were included in the study. The surface protein-encoding gene (S gene) in the HBV genome was subjected to amplification and partial sequencing.
  
  
  RESULTS
  Based on phylogenetic analysis, only genotype D was found circulating among patients. The majority of isolates belonged to subgenotype D3 (86.3%), followed by D7 (8%), then D5 (3.4%) and lastly D1 (2.3%). Two subtypes were identified: ayw2 (97%) and ayw3 (2%). The 'w' sub-determinant was not defined in one isolate (1%). A significant proportion of patients (13/88, 14.8%) exhibited mutations in the MHR, 10 of whom harboured mutations in the 'a' determinant region and three outside. The first loop comprised four patients with three mutations (P127S, P127T and Y134F). The second loop contained six patients, all with one mutation, S143L, which was most frequently encountered in this study (6.8%).
  
  
  CONCLUSIONS
  We conclude that genotype D, subgenotype D3 and HBsAg subtype ayw2 are the most common types circulating in Egypt, which account for 100%, 86.3% and 97% of the population, respectively, with a moderate degree of MHR mutations.
authors.affiliation: Central Laboratories of the Ministry of Health, Cairo, Egypt.
authors.forename: Walaa M
authors.initials: WM
authors.lastname: Abu Zeid
authors.affiliation: Department of Clinical and Chemical Pathology, Kasr Alainy School of Medicine, Cairo University, Cairo, Egypt. Electronic address: dramadan7371@yahoo.com.
authors.forename: Dalia I
authors.initials: DI
authors.lastname: Ramadan
authors.affiliation: Department of Biochemistry & Molecular Biology, Theodor Bilharz Research Institute, Giza, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Shemis
mesh_terms: D000328:Adult; D004534:Egypt; D005260:Female; D005838:Genotype; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D008875:Middle Aged; D009154:Mutation; D058974:Phylogeography; D055815:Young Adult
chemical_list: D006514:Hepatitis B Surface Antigens
keywords: HBV genotypes; HBsAg subtypes; MHR variants; Major hydrophilic region