Direct DNA amplification and restriction pattern analysis of Helicobacter pylori in patients with duodenal ulcer and their families.

Sera from 14 patients with duodenal ulcer and their families were tested for IgG antibodies to Helicobacter pylori. Fourteen serologically negative patients and their families served as controls. Index patients and their family members who were serologically positive were advised to undergo endoscopic biopsy. Gastric biopsy tissues were subjected to HaeIII restriction analysis of nested polymerase chain reaction products of the urease gene. By serology, 28 (49.0%) of 57 in index families and 11 (27.5%) of 40 in control families tested positive. A higher prevalence rate was found in children of index patients (11/31, 35.5%) than in those of control patients (1/18, 5.6%; P < .05). On DNA analysis, 11 patterns were found in 13 patients, and 6 families underwent endoscopy. Children in 5 families exhibited identical patterns to those of their siblings and, in 3 of the 5 families, identical to the pattern of 1 of the parents. These results suggest that parent-to-child transmission and common infection source are probable causes of intrafamilial clustering of H. pylori.