Association of Nonsynonymous Substitutions in the Intermediate Region of the <i>vacA</i> Gene of <i>Helicobacter pylori</i> with Gastric Diseases in Taiwan

Abstract

The amino acid sequences corresponding to the vacA intermediate region from 39 isolates of Helicobacter pylori were investigated. The substitution of a G for the third S in the i1-type cluster B sequence (QASEGITSSK) conferred a greater risk of gastric diseases (P < 0.03; Fisher's exact test). The conserved substitutions of an F for the Y in the cluster A sequence and of an M for the second N in the i1-type cluster C sequence could be a marker of VacA in the Taiwanese strains.