HAX1 and neutropenia: Depending on the type of the inherited gene mutation, SCN patients exhibit either isolated neutropenia (ELANE mutations) or additional syndromes such as lymphopenia (GFI1 gene mutations); monocytopenia (WAS-mutations); mental retardation/seizures (HAX1 mutations); prominent superficial venous network, atrial defects, and uropathy (G6PC3-associated disorders); and albinism and hyper-gammaglobulinemia (p14-mutated patients).