PPW Lee, TL Lee, MHK Ho, PCY Chong, CC So, YL Lau

Abstract

Severe congenital neutropenia (SCN) is a rare, heterogeneous group of inherited disorders of neutrophil precursors presenting with pyogenic infections and severe neutropenia in infancy. We hereby describe an infant with persistent omphalitis and severe neutropenia. The diagnosis of SCN was confirmed by typical bone marrow findings. However, the response to usual dose of granulocyte colony-stimulating factor (G-CSF) was suboptimal. The requirement of high dose G-CSF suggests a higher risk of malignant transformation into myelodysplastic syndrome or acute myeloid leukaemia, and close monitoring for clonal changes and progression to frank leukaemia is needed. In this article we discussed the clinical approach to omphalitis, a condition commonly encountered by paediatricians, as well as differential diagnosis of neutropenia in neonates and infants. We also summarise the molecular etiologies and pathogenesis underlying SCN, which has only been unraveled in the past few years. While majority of patients with SCN respond to G-CSF which significantly reduces the risk of infections and mortality, dosage of G-CSF should be carefully titrated. Patients requiring high-dose G-CSF should be closely monitored for developing malignant transformation, which is uniformly associated with poor prognosis despite chemotherapy and hematopoietic stem cell transplantation.