The copy number status of TET2 (on 4q24), IRF1 (5q31.1), NPM1 (5q35.1), LAMB4 (7q31.1), EZH2 (7q36.1), ETV6 (12p13.2), TP53 (17p13.1), NF1 (17q11.2), ASXL1 (20q11.21), RUNX1 (21q22.12), and STAG2 (Xq25) have been investigated in a large cohort of MDS patients18. The gene discussed is STAG2; the disease is myelodysplastic syndrome.