[Severe congenital neutropenia: analysis of clinical features, diagnostic methods, treatment and long-term outcome]

Severe congenital neutropenia (SCN), a heterogeneous condition with onset at early ages, is characterised by primary myelopoiesis failure with an absolute neutrophil count (ANC) < 0.5 x10(9)/L, severe infections and risk of leukaemic transformation.

The aim of the study was to ascertain the long term outcome of patients with SCN.

The clinical features, diagnostic methods, treatment and outcome of 11 patients with SCN were analysed.

The median age at diagnosis was 4 months (range: 3 days-12 years). The primary clinical manifestation was severe infection. Median ANC at diagnosis: 0.2 x 10(9)/L (range: 0-0.37). Bone marrow aspirate showed maturation arrest at promyelocyte stage in all cases. Genetic studies revealed 3 mutations, two in ELA-2 gene and 1 in G6PC3 gene, showing a correlation between genotype and phenotype. Granulocyte Colony Stimulating Factor (G-CSF) was the first-line treatment in 9 patients; six of whom showed a good response at doses between 5 and 15 μg/kg/day for 3-7 days/week. The remaining 3 patients failed to respond to G-CSF and allogeneic stem cell transplantation (SCT) was indicated. Furthermore, SCT was the treatment of choice in two cases. Median follow-up of the cohort was 5 years (range: 1-10 years) with 100% survival and no cases of leukaemic transformation.

We conclude that genetic study is useful for establishing a correlation between genotype and phenotype. The treatment of choice for SCN is G-CSF to which 2/3 of patients should respond; while SCT is reserved for cases of poor response or those evolving to myelodysplastic syndrome (MDS) or leukaemia; thus close follow-up of this condition is essential.