The increased expression or/and truncation of HMGA2 has been observed in patients with both MDS and PNH, in which the common feature is marrow failure [70,73,143]; the failure is in part due to the immunological injury of HSC orchestrated by the self-reactive cytotoxic T lymphocytes (CTL) that secrete the Tumor Necrosis Factor-α (TNF-α) and Interferon-γ (INF-γ) [144,145,146]. The gene discussed is HMGA2; the disease is myelodysplastic syndrome.