For cases that lack excess blasts or Auer rods and do not qualify for any of the three genetically-defined groups [SF3B1, bi-allelic TP53, or del(5q)], the ICC subdivides cases by the presence of dysplasia involving one (single lineage dysplasia, SLD) or more (multilineage dysplasia, MLD) hematopoietic lineages, while the WHO-HAEM5 introduced a new entity of hypoplastic MDS (MDS-h), defined by age-adjusted hypocellularity (cellularity < 20% for patients ≥70 years and < 30% for patients < 70 years). This evidence concerns the gene TP53 and myelodysplastic syndrome.