Dyskeratosis congenita with isolated neutropenia and granulocyte colony-stimulating factor treatment

A 3-year-old Turkish boy with a history of chronic cough, recurrent bronchopneumonia, and a borderline sweat chloride test (40 mEq/L) was referred for further evaluation to our department. He was born at term (2100 g) to a marriage with no consanguinity. His mother and father were 40 and 46 years old, respectively. Physical examination (Fig. 1) revealed hypopigmented, atrophic, and hyperkeratotic skin lesions surrounded by reticulate hyperpigmentation on the entire body, predominantly on the face, neck, arms, shoulders, and legs, which had been noticed initially at the age of 18 months. Dystrophic toenails, sparse and thin hair, and phimosis were also observed. Laboratory tests disclosed an isolated neutropenia (white blood cell count, 1800/mm3). Bone marrow (BM) aspiration showed a decreased myelopoiesis without myelodysplastic changes, but normal erythropoiesis, megakaryopoiesis, and normal stroma. Lymphocyte subgroups containing CD4, CD5, CD6, CD8, CD19, CD23, and CD25, and immunoglobulin G (IgG), IgM, IgA, and IgE, were in the normal range; hemoglobin F (HbF), 2.8%. Spontaneous and clastogen-induced chromosome breaks were not increased. A skin biopsy showed increased pigmentation at the basal layer, dyskeratotic epidermal cells, and marked IgM deposition and cytoid bodies and mild IgA and IgG deposits at the dermo-epidermal junction. Lactate response to glucose challenge, amino acid chromatography, and urine organic acid analysis were normal. A diagnosis of dyskeratosis congenita (DC) was made with typical skin lesions, dystrophic toenails, thin and sparse hair, and neutropenia with decreased myelopoiesis in BM. Treatment with granulocyte colony-stimulating factor (G-CSF) was considered for the neutropenia. As the increase in neutrophil count at a dose of 5 microg/kg was not adequate, 10 microg/kg G-CSF was tried (Fig. 2). With 10 microg/kg once to three times a week, a 1.8-4.8-fold increase in the absolute neutrophil count (ANC) was achieved with no side-effects. Treatment was more frequent during infection (days 22-28).