Congenital dyserythropoietic anemia type I. Report of a case.

A new case of congenital dyserythropoietic anemia type I is reported in a 12-year-old Spanish boy. In regard to the morphological study at an optical and ultrastructural level, the most outstanding feature was the internuclear bridging connecting two erythroblastic nuclei within a single cytoplasm or stretched between two erythroblasts perfectly individualized.