A point mutation in the cytoplasmic domain of the granulocyte colony-stimulating receptor (G-CSFR) in a patient with myelokathexis

We describe a case of familial congenital neutropenia with abnormal morphology of neutrophils, typical of myelokathexis with impaired granulocyte function expressed as low chemotaxis, impaired bactericidal activity and subnormal superoxide production. A mono allelic point mutation at nucleotide 2429 of the cytoplasmic domain of the G-CSF receptor was demonstrated in one of the patients but not in other family members. It is suggested that the occurrence of such somatic G-CSFR activating mutations may confer growth advantage via increased proliferation rate or decreased apoptosis, similar to the situation in the subset of severe congenital neutropenic patients where such activating mutations were described.