A rare family was reported where acute leukemia developed in three members over a period of 7 years. Case 1, a 59-year-old man, was diagnosed to have acute myeloblastic leukemia in June, 1959. Case 2, a daughter of the patient in case 1, was hospitalized with complaints of fever, malaise and petechiae at the age of 29 years, and the diagnosis of acute lymphoblastic leukemia was made in January, 1976. A thorough taking of the family history disclosed another case of leukemia in a distant relative, a son of the niece of case 1, where acute myeloblastic leukemia occurred in December, 1970. There existed no evidence of consanguinity in this family. Cases 1 and 2 had lived in the same house until the occurrence of leukemia in case 1, while case 3 lived in a different location. Common environmental factors such as ionizing radiations and toxic chemicals could not be detected among the three cases. The occurrence and significance of familial leukemia in relation to pathogenesis of leukemia were discussed.
