Lessons from congenital neutropenia: 50 years of progress in understanding myelopoiesis.

Severe congenital neutropenia (SCN) was first described just over 50 years ago. The progress in elucidating the clinical features and molecular pathophysiology of SCN closely parallels the progressive growth in our understanding of myelopoiesis. In this historical review, I have delineated this parallel progression in our understanding of the processes of granulocyte differentiation and the pathogenesis of congenital neutropenia. SCN is a heterogeneous disease that can serve as a model for the failure of myelopoiesis, and dissection of its pathogenesis has yielded important insights into the normal process of myeloid development.