A novel 203 kD aberrant BCR-ABL product in a girl with Philadelphia chromosome positive acute lymphoblastic leukaemia.

We report a girl with Ph1-positive ALL with the aberrant BCR-ABL product. In this case, bcr exon 3 jointed not to ordinal abl exon 2 but to exon 3 resulting in the production of a 203 kD BCR-ABL fusion protein with marked tyrosine kinase activity. To our knowledge, this is the first report of an aberrant BCR-ABL product in childhood. This case was characterized with younger age and low leucocyte count at the onset, but relapsed early like the typical Ph1-positive ALL, suggesting the diversity in the clinicopathogenesis of Ph1-positive ALL.