1. The deletion of the entire chromosome 7 or the entire long arm 7q is a recurrent abnormality of MDS. It happens in approximately 5-10% AML(M4 and M6) ,in approximately 15% adult MDS, 40% child MDS and 50% treatment-related AML/MDS. Most of the deletion region are q11-22 and Q31-36 within 7q.
2. It has poor prognosis and often prone to infection and leukocyte transformation.