RUNX1 and myelodysplastic syndrome: aCN-LOH as a sole genomic abnormality is a recurrent finding in MDS with normal karyotypes and these regions often harbour point mutations in genes associated with poor outcome in MDS such as ASXL1, EZH2, TP53 and RUNX1. Mutation screening with NGS panels is therefore strongly recommended in cases with aCN-LOH and a good IPSS-R score.