t(1;21)(p36;q22)

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A chromosomal translocation involving breakpoints within the p36 band on the short arm of chromosome 1 and the q22 band on the long arm of chromosome 21. This translocation may be associated with RUNX1-PRDM16 fusion gene expression and myelodysplastic syndrome or acute myeloid leukemia.