STUB1 and myeloid neoplasm: Although the presence of CHIP mutations usually does not affect red cell distribution width (RDW), clonal cytopenia of undetermined significance (CCUS) [104–106] is characterized by the presence of M-CHIP along with one or more persistent cytopenias that cannot be explained by other hematologic or non-hematologic conditions and do not fulfill the diagnostic criteria for specific myeloid neoplasms.