Similar heterozygous C-terminal truncations are sufficient to induce myelodysplastic syndrome.25 Previously observed frameshift or nonsense mutations in ASXL1 across numerous tumor types catalogued in The Cancer Genome Atlas (TCGA) have been observed both upstream and downstream of amino-acid 657, with the highest concentration centered at position 657 (Figure 3). This evidence concerns the gene ASXL1 and myelodysplastic syndrome.