SRP54 and cyclic hematopoiesis: Among them, 65 patients were diagnosed with SCN or cyclic neutropenia (CyN), distributed as follows: SCN1/CyN caused by defects in the ELANE gene, n = 44; SCN2 (GFI1 gene defects), n = 2; SCN4 (G6PC3 gene defects), n = 1; SCN6 (JAGN1 gene defects), n = 1; SCN8/Shwachman–Diamond-like syndrome (SRP54 gene defects), n = 7; and SCN9 (CLPB gene defects), n = 10.