UBA1 and myelodysplastic syndrome: Bone marrow examination lead to a formal diagnosis of myelodysplastic syndrome (MDS) in all patients, falling into the MDS with low blasts (MDS-LB, n = 4) and MDS with increased blasts type 1 (MDS-IB1, n = 1).11 Of note, the bone marrow was hyper cellular in all of them, as also described in VEXAS patients.2 However, on the contrary to classical VEXAS, UBA1 AAD mutant patients had marked erythroid hyperplasia (from 50% to 80% of total bone marrow cells).