Influence of the type of family predisposition on the age of ulcer disease onset.

736 probands with endoscopically and/or roentgenologically proven ulcer disease of the stomach and duodenum were studied. Of these 429 were with hereditary predisposition to the disease (including in the study all their third-degree relatives). Our findings suggest that the age of disease onset is markedly dependent on the type of familial predisposition. It occurs the earliest and relatively the most frequently in probands with two affected parents (familial predisposition type III). The peak frequency of the disease for non-predisposed subjects is between 30 and 39 years of age while in subjects with familial predisposition of the first type (two healthy but genetically predisposed parents) the II-A type (a sick father) and the II-B type (a sick mother) it occurs a decade earlier. Type III familial predisposition causes the disease to affect the probands even earlier by another decade so half of all the probands of this type of familial predisposition are affected by the disease by the age of 19. The different types of familial predisposition to gastric ulcer (types II and III) and duodenal ulcer reflect the hereditary ulcerogenic load received by the offspring. All other conditions being equal, the greater it is the earlier the disease occurs.