The value of investigations of the incidence of peptic ulcer in the families of patients with duodenal ulcer.

Many exogenous and endogenous factors are involved in the development of peptic ulcers. These factors are of individual importance for each subject and probably vary with time (Vesely, Kubickova', and Dvoraikova, 1968). At present, great importance is ascribed to hereditary factors, though it is difficult to produce the necessary evidence (Bauer and Aschner, 1922; Fuirst, 1936; Dubarry, Pisot, and Duhamel, 1960; Levrat, Lambert, and Bourrat, 1960; Levrat, Lambert, and Tissot, 1962; Jira'sek, Gregor, and Cerny, 1964 and 1965; Jirasek, 1967). Direct heredity is not assumed but rather a familial disposition conditioned by some genetically determined characteristics, either morphological, biochemical, or functional (Guiss and Stewart, 1948; Meyers, 1948; Tongen, 1950; Cox, 1952; Illingworth, 1956; Card and Marks, 1960; Shay and Sun, 1963; Landor, Portefield, and Wolff, 1966; Fodor et al, 1968). Among the genetically determined characteristics investigated were blood groups of the ABO system (Clarke et al, 1959; Doll, Drane, and Newell, 1961; Kubickova' and Vesely, 1966; Vesely et al, 1968), the secretor status of ABH blood group substances (Roberts, 1957; Levrat et al, 1960; Newman et al, 1961; Buckwalter, 1962; Kubickova, 1964; Caldwell and Pigman, 1965; Langman and Doll, 1965; McConnell, 1966), and recently also the phenylthiocarbamide (PTC) test, ie, the ability to taste various concentrations of PTC (Kaplan et al, 1964; Kubickovia, Dvorakovai, and Vesely, 1968; Vesely et al, 1968). The relationship of the ABO blood groups to peptic ulceration has been investigated in the greatest detail. Based on many well-documented publications from various countries a proven relationship is considered to exist between duodenal ulcer and blood group 0 (Melrose and Wallace, 1965; Vesely et al, 1968; Lambert and Martin, 1969).