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

Introduction: 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.

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

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

Results: 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.

Conclusions: 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.