Acquired Pyruvate Kinase Deficiency In Clonal Myeloid Neoplasms

Inclusion Criteria: * Cohort 1 * Capable and willing to provide informed consent for participation in the study. * Diagnosis of clonal cytopenia of undetermined significance (CCUS), myelodysplastic syndrome (MDS) or myelodysplastic/myeloproliferative neoplasm (MDS/MPN syndrome) according to 2016 World Health Organization (WHO) classification system. * Anemia secondary to underlying clonal cytopenia of undetermined significance (CCUS), MDS or MDS/MPN syndrome, defined as a hemoglobin \<11.0 g/dL measured within 30 days of study enrollment. Anemia should not be related to nutritional deficiency (such as iron, cobalamin, folate, or copper deficiencies), peripheral immune or non-immune hemolysis, or renal disease, in the opinion of the investigator. * Age \>18 years. * Cohort 2 * Capable and willing to provide informed consent for participation in the study. * Diagnosis of a clonal myeloid neoplasm, such as MDS, MDS/MPN syndrome, myeloproliferative neoplasm (MPN), acute myeloid leukemia (AML), clonal cytopenia of undetermined significance (CCUS), or other clonal myeloid neoplasm according to 2016 World Health Organization (WHO) classification system. * A diagnosis of an otherwise unexplained Coombs-negative non-immune hemolytic anemia, according to the clinical judgement of the investigator. Some form of objective laboratory evidence must be present, including one or more of the following: negative direct antiglobulin (Coombs) test, reduced haptoglobin, elevated …