Thirteen cases of leukemia in a family.

Thirteen cases of leukemia, 12 of them acute, occurred in 3 generations of a family comprising 293 members. Individual cases could not be linked to the possession of any of a range of genetic markers. Cytogenetic studies showed no constitutional chromosome abnormalities. Preliminary results of virologic studies suggested the presence of oncornaviruses in at least 1 leukemic individual in this family. This aggregation of leukemia cases likely resulted from a genetic, probably polygenic, predisposition, in association with the activity of leukemogenic factors whose nature remains to be clearly defined.