CLPB variants in genetically unresolved SCN. Heterozygous missense ATP-binding pocket variants in CLPB act in a dominant-negative manner and disrupt wild-type (WT) CLPB function. Expression of CLPB variant is associated with mitochondrial dysfunction, increased apoptosis, and impaired granulocytic differentiation in HSPCs. ADP, adenosine 5′-diphosphate; ATPase, adenosine triphosphatase; Mut, mutant.