During embryonic development of the brain cortex in mouse, PML regulates the transition from radial glia cells to basal progenitors.18 In addition, PML is required for maintenance and asymmetric commitment of hematopoietic stem cells.19 A recent study demonstrated a neuroprotective effect of PML in a mouse model of spinocerebellar ataxia 1.11 It is not clear, however, if PML participate in differentiation and/or tissue morphogenesis after injury in neonatal or adult animals. Here, PML is linked to spinocerebellar ataxia type 1.