Knockout of histone deacetylases HDAC1 or HDAC2 affects hematopoiesis, while simultaneous knockout of HDAC1 and HDAC2 results in severe HSC defects, leading to anemia and reduced blood cell counts, indicating functional redundancy between HDAC1 and HDAC2 in hematopoiesis.131. The gene discussed is HDAC1; the disease is anemia (phenotype).