Severe congenital neutropenia (Kostmann Syndrome)
Severe congenital neutropenia (SCN), Kostmann syndrome is a heterogenous disorder of myelopoiesis characterized by severe chronic neutropenia, absolute neutrophil count (ANC) persistently below 0.50 x 109/L, with maturation arrest of neutrophil precursors in the bone marrow; and associated with serious recurrent bacterial infections from early infancy. Sepsis mortality is reduced by an advent of granulocyte colony stimulating factor (G-CSF) therapy. More than 90% of patients respond to G-CSF therapy. However, hematopoietic stem cell transplantation has shown promise in the treatment of non-responders. About 60-80% of SCN cases are associated with constitutive mutations in one copy of the gene encoding neutrophil elastase ELA2. Myelodysplastic syndrome and acute myeloid leukemia (MDS/AML) have been reported. The hazard of MDS/AML increases significantly overtime. Approximately 10% of patients with severe congenital neutropenia develop AML. This is not thought to be the direct result of G-CSF therapy but related to the underlying disease itself.
Key Words: Myeloid leukemia, congenital neutropenia, kostmann’s syndrome, myelodysplastic syndrome.