Congenital neutropenia.

Congenital neutropenia comprises a variety of genetically heterogeneous phenotypic traits. Molecular elucidation of the underlying genetic defects has yielded important insights into the physiology of neutrophil differentiation and function. Non-syndromic variants of congenital neutropenia are caused by mutations in ELA2, HAX1, GFI1, or WAS. Syndromic variants of congenital neutropenia may be due to mutations in genes controlling glucose metabolism (SLC37A4, G6PC3) or lysosomal function (LYST, RAB27A, ROBLD3/p14, AP3B1, VPS13B). Furthermore, defects in genes encoding ribosomal proteins (SBDS, RMRP) and mitochondrial proteins (AK2, TAZ) are associated with congenital neutropenia syndromes. Despite remarkable progress in the field, many patients with congenital neutropenia cannot yet definitively be classified by genetic terms. This review addresses diagnostic and therapeutic aspects of congenital neutropenia and covers recent molecular and pathophysiological insights of selected congenital neutropenia syndromes.