USP9X and myelodysplastic syndrome: For this purpose, we preselected FAM (a member of the SINE clade of non-LTR retrotransposons, one of the most highly expressed TEs, reduced in LR-MDS), HERV-Fc1 (a member of the ERV1 clade of LTR retrotransposons, the most significantly dysregulated TE, increased in MDS samples compared with controls), and piR_018780 (one of the most highly expressed piRNAs, increased in HR-MDS).