Furthermore, high HDAC4 expression levels were detected in a mouse model of spinal muscular atrophy in ALS patients and in an ALS mouse model, suggesting that in the presence of neuromuscular defects, inactivation of HDAC4 may result in a suppression of muscle atrophy in a denervation model [113,114]. Here, HDAC4 is linked to proximal spinal muscular atrophy.