The propositus, age 58 male, complained of bloody mucoid discharge and was admitted to Nagoya University Hospital, August 1973. In July 1977, the son, age 29, was admitted with the same complaint. Barium enema (Figure 1, 4), undertaken on both patients, showed findings of ulcerative colitis invading the total colon. Sigmoidscopic examination and biopsy specimens (Figure 2, 5) confirmed these findings. Several months of drug treatment led to total remission in the father's disease and temporary in the son's. (Figure 3, 6) Recently, the son experienced a relapse. (Figure 7 colour) Twenty one cases of ulcerative colitis were found among 10 Japanese families, (Table 1) (In western countries, the frequency of occurrence is much higher.) Of these 10 families, parent-child occurrence was found in 5 ; 3 were mother-daughter, 1 was mother-son, and 1 was father-son. In the other 5 families, occurrence was among siblings ; 3 between brothers, 1 between sisters, and 1 among three siblings. In the three families of which afflicted persons lived together, the involvement of genetic, environmental, and psychological factors is suggested. In the other three families of which afflicted persons did not live together, a genetic etiology of the disease is suggested.
