CSF3R and chronic neutrophilic leukemia: In addition, we found recurrent mutations in CSF3R and DHX15. Acquisition of extracellular point mutations and mutations that truncate the cytoplasmic domain of CSF3R is a common phenomenon in severe congenital neutropenia (SCN) and chronic neutrophilic leukemia patients and leads to ligand-independent activation of the receptor and thus, to JAK-STAT, MAPK-ERK, and PI3K-AKT signaling pathway activation [28, 29].