We compared 40 patients harboring CSF3R mutations (12 ELANE-CN, 9 HAX1-CN, 1 JAGN1-CN, 3 CN-MDS/AML, 13 genetically unclassified CN and 2 CyN patients) with 54 patients without CSF3R mutations (10 ELANE-CN, 9 HAX1-CN, 2 G6PC3-CN, 1 JAGN1-CN, 1 CN-MDS/AML, 11 genetically unclassified CN, 7 CyN, 6 SDS, 1 idiopathic neutropenia patients as well as 6 patients with inherited syndromes associated with severe neutropenia (3 Cohen syndrome, 1 Barth syndrome, 1 WHIM, 1 GSDIb). Here, HAX1 is linked to Decreased total neutrophil count.