The first is the region of glycophorins genes (GYPE, GYPA, GYPB) on chr4, erythroid surface markers [59]: this reinforces the concept of a disturbance of multilineage myeloid hematopoiesis in DS AMKL and has been observed by flow cytometry in the non-neoplastic hematopoiesis itself in trisomy 21 [60]. The gene discussed is GYPB; the disease is trisomy 21.