CD34 and metachromatic leukodystrophy: The latest addition is the approval of Libmeldy®, an ex vivo gene therapy with lentivirus vector (LV)-transduced autologous CD34-positive hematopoetic stem and pluripotent cells (HSPCs) for treatment of metachromatic leukodystrophy, in Europe in 2020 (Bulaklak and Gersbach, 2020).