Interferon alpha is an effective therapy for congenital dyserythropoietic anaemia type I.

The efficacy of interferon-alpha (IFN) was reported in three patients with congenital dyserythropoietic anaemia (CDA) type I. We describe two additional cases treated with IFN, which normalized the haemoglobin level in both patients with a dramatic decrease in the size of the spleen in one. Haemoglobin remained stable more than 6 months after discontinuation of treatment. IFN induced more than 50% decrease in the number of BFU-E in both patients' bone marrow cultures, suggesting an indirect effect of IFN on erythropoiesis in vivo. We conclude that a trial of IFN therapy should be considered in patients with CDA type I.