A high prevalence of cardiac comorbidity was observed in patients with myelodysplastic syndromes with loss of chromosome Y (22 [41%] of 54 patients), and no significant effect of mutations in genes related to clonal haematopoiesis (ASXL1, DNMT3A, and TET2) was noted on the prevalence of cardiac disease (p=0·48). Here, ASXL1 is linked to myelodysplastic syndrome.