Doublede novomutations ofELANE(ELA2) in a patient with severe congenital neutropenia requiring high-dose G-CSF therapy

Case Report: Characterization of known (c.607G>C) and novel (c.416C>G) ELANE mutations in two Mexican families with congenital neutropenia

The most common causes of congenital neutropenia are mutations in the ELANE (Elastase, Neutrophil Expressed) gene (19p13.3), mostly in exon 5 and the distal portion of exon 4, which result in different clinical phenotypes of neutropenia. Here, we report two pathogenic mutations in ELANE, namely, c.607G>C (p.Gly203Arg) and a novel variant c.416C>G (p.Pro139Arg), found in two Mexican families ascertained via patients with congenital neutropenia who responded positively to the granulocyte colony-stimulating factor (G-CSF) treatment. These findings highlight the usefulness of identifying variants in patients with inborn errors of immunity for early clinical management and the need to rule out mosaicism in noncarrier parents with more than one case in the family.

Incidence of severe congenital neutropenia in Sweden and risk of evolution to myelodysplastic syndrome/leukaemia

Severe congenital neutropenia (SCN) is characterized by low blood neutrophil counts, early bacterial infections, and risk of leukaemia development. As yet, no population-based incidence estimates of SCN have been reported. Children less than 16 years of age with SCN were sought in Sweden during the 20-year period 1987-2006 by a questionnaire to all Swedish Departments of Paediatrics and by reviewing the Swedish Health and Welfare Statistical Databases. Thirty-two patients were diagnosed with congenital neutropenia during this period. All received treatment with recombinant granulocyte-colony stimulating factor (G-CSF). Twenty-one patients were diagnosed as SCN or probable SCN, corresponding to 1·0 per 100,000 live births. Nine (43%) had ELANE mutations, four (19%) HAX1 mutations and eight (38%) were children with disease of unknown genetic aetiology. Four out of 21 patients (19%) developed myelodysplastic syndrome/leukaemia and three (14%) died, all with leukaemia. The cumulative incidence of myelodysplastic syndrome/leukaemia was 31%. The observed incidence of SCN in this population-based study was higher than previously estimated, possibly because genetic testing now can identify SCN cases previously thought to be idiopathic or benign neutropenia. The risk of developing myelodysplastic syndrome/leukaemia is considerable. ELANE mutations are the most commonly identified genetic defects.