TPP1 and proximal spinal muscular atrophy: Indeed, within both the SMA and the lysosomal storage disorder fields (of which CLN2 is amongst a family of over 13 heritable diseases), the relevance of even well-established animal or in vitro modelling strategies remains contentious, rendering it difficult to define disease-specific pathophysiology at even a gross neuroanatomical level, much less on a cellular or molecular basis [9,10,11,12].