Fifteen cases of t(1;19)(q23;p13.3) identified in an Australian series of 122 children and 80 adults with acute lymphoblastic leukemia

The t(1;19)(q23;p13) has been reported in up to 6% of cytogenetically abnor mal cases of acute lymphoblastic leukaemia (ALL), associated with a pre-B-A LL phenotype. In the 5-year period 1995-1999, we detected t(1;19) in 13 chi ldren and 2 adults with newly diagnosed ALL. This represented 10% of pediat ric and 2.5% of adult diagnostic ALL. samples successfully cultured in one center during this time. There were 9 males and 6 females. The mean age at diagnosis for the 13 children was 6.5 years (range 1.5 to 14 years) and the 2 adults were aged 42 and 45 years. The unbalanced t(1;19) occurred in 7 o f 13 children (54%), contrary to the reported excess of unbalanced transloc ations at 75%; both adults had the unbalanced translocation. At diagnosis, the t(1;19) was the sole abnormality in 4 patients (26%), and in the remain der (74%) was part of a complex karyotype, which included i(7q) (2 patients ), hyperdiploidy (2 patients) and del(6q) (2 patients). Correlation of kary otype with white cell, blast and platelet counts, cell surface markers, ini tial response to chemotherapy and short tem outcome showed no difference be tween the balanced and unbalanced forms of the translocation in children or whether t(1;19) was present as the sole abnormality or part of a complex k aryotype. (C) 2001 Elsevier Science Inc.