For example, in mice with MPS IIIA, reduced levels of SNAP25 and VAMP2 proteins parallel decreases in synaptic vesicles, abnormal vacuoles, and enlarged mitochondria in axonal termini (Sambri et al., 2017), but surprisingly, without defects in the expression of SNAP25 and VAMP2 mRNAs. This evidence concerns the gene VAMP2 and mucopolysaccharidosis type 3A.