IT HAS BEEN documented that individuals with the Down syndrome have trisomy 21 and an increased level of polymorphonuclear leukocyte alkaline phosphatase.1-3 On the other hand, a small acrocentric chromosome (Philadelphia chromosome) and low levels of leukocyte alkaline phosphatase have been found in association with chronic myelogenous leukemia.4,5 An increased incidence of acute leukemia in patients with the Down syndrome has been observed and approximates 15 times that expected in the general population.6 These findings have suggested that changes in chromosome 21 play some role in the pathogenesis of acute and chronic myelogenous leukemia (CML) and the Down syndrome. It is the purpose of this communication to describe an adult patient with many features of the Down syndrome, CML, low leukocyte alkaline phosphatase, and the Philadelphia (Ph1) chromosome.
Report of a Case
A 42-year-old white woman was first seen in May of 1962. She had been well until one