Leukemia in Identical Twins

Abstract
ACUTE leukemia of childhood has thus far defied etiologic definition. Environmental or infectious factors have been suggested as being causes,1 and the occurrence of familial cases has been cited as possibly indicating genetic influences.2 The study of the pattern of diseases as they occur in twins is a recognized method for investigating etiology.3 If genetic influences are strongly operative in a disease both members of a pair of identical twins will usually be affected (concordancy); if both are not usually affected (discordancy), environmental factors are indicated as being etiologically important.Case ReportsTwin A. A 3I/2-year-old boy was first admitted . . .