In severe congenital neutropenia (SCN), long-term therapy with granulocyte 
colony-stimulating factor (G-CSF) has reduced mortality from sepsis, revealing 
an underlying predisposition to myelodysplastic syndrome and acute myeloid 
leukaemia (MDS/AML). We have reported the early pattern of evolution to MDS/AML, 
but the long-term risk remains uncertain. We updated a prospective study of 374 
SCN patients on long-term G-CSF enrolled in the Severe Chronic Neutropenia 
International Registry. Long-term, the annual risk of MDS/AML attained a plateau 
(2.3%/year after 10 years). This risk now appears similar to, rather than higher 
than, the risk of AML in Fanconi anaemia and dyskeratosis congenita.