Monosomy 7, leukaemia and immunoglobulin heavy chain gene rearrangement

We describe the haematological findings and clinical course of a 15-year-old male who presented with a spontaneous acute lymphoblastic leukaemia. The lymphoid origin of the leukaemia was supported by cell surface antigen studies and immunoglobulin heavy chain gene analysis. Bone marrow karyotype was simple monosomy 7 and the lymphoblasts expressing the myeloid associated antigen CD 33. Both of these features have been previously shown to indicate a poor prognosis. The findings in this patient support a previous hypothesis that monosomy 7 can arise at the stem cell level.