In a follow-up study, they used three phenotypically distinct SMA mouse models and again confirmed that SMN-dependent missplicing of Mdm2 and Mdm4, causing p53 nuclear accumulation, is a conserved pathological mechanism, while the inhibition of p53 prevents motor neuron death in severe and moderate SMA mouse models (Buettner et al., 2021). The gene discussed is MDM4; the disease is proximal spinal muscular atrophy.