Cytogenetics of juvenile type chronic granulocytic leukemia.

Cytogenetic examination of bone marrow cells from three patients with juvenile chronic granulocytic leukemia (CGL) showed 46,XX,3p-,11p+ ,t(11p:3p) in one case, 45XY,-E in another, and 45X(X),-C/47,XX,+G in the third. The case with the translocated chromosome originally presented like an acute lymphocytic leukemia (ALL). TAn overt clinical picture of juvenile CGL emerged two and a half years later. Serial study of this case revealed no cytogenetic abnormalities until two years after the diagnosis of ALL, when the translocated chromosome was first observed. Unlike the Ph1 chromosome in adult type CGL, chromosomal abnormalities in juvenile CGL lack specificity, resembling ALL in this respect.