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Single Nucleotide Polymorphisms of Helicobacter pylori dup A that Lead to Premature Stop Codons
Author(s) -
Moura Sílvia B.,
Costa Rafaella F. A.,
Anacleto Charles,
Rocha Gifone A.,
Rocha Andreia M. C.,
Queiroz Dulciene M. M.
Publication year - 2012
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/j.1523-5378.2011.00933.x
Subject(s) - helicobacter pylori , gene , population , stop codon , gastritis , helicobacter , medicine , biology , genetics , environmental health
Background: The detection of the putative disease‐specific Helicobacter pylori marker duodenal ulcer promoting gene A ( dup A) is currently based on PCR detection of jhp0917 and jhp0918 that form the gene. However, mutations that lead to premature stop codons that split off the dup A leading to truncated products cannot be evaluated by PCR. Methods: We directly sequence the complete dup A of 75 dup A‐positive strains of H. pylori isolated from patients with gastritis (n = 26), duodenal ulcer (n = 29), and gastric carcinoma (n = 20), to search for frame‐shifting mutations that lead to stop codon. Results: Thirty‐four strains had single nucleotide mutations in dup A that lead to premature stop codon creating smaller products than the predicted 1839 bp product and, for this reason, were considered as dup A‐negative. Intact dup A was more frequently observed in strains isolated from duodenal ulcer patients (65.5%) than in patients with gastritis only (46.2%) or with gastric carcinoma (50%). In logistic analysis, the presence of the intact dup A independently associated with duodenal ulcer (OR = 5.06; 95% CI = 1.22–20.96, p = .02). Conclusion: We propose the primer walking methodology as a simple technique to sequence the gene. When we considered as dup A‐positive only those strains that carry dup A gene without premature stop codons, the gene was associated with duodenal ulcer and, therefore, can be used as a marker for this disease in our population.