RAB11A and mucopolysaccharidosis type 2: To assess this hypothesis, we analyzed three genes involved in the endolysosomal pathway well known to be dysregulated in MPS II [2,4,26] by RT-qPCR: Autophagy-related protein 8a (Atg8a), which encodes an ubiquitin-like protein and whose product has a role in autophagosome formation; Lysosomal-associated membrane protein 1 (Lamp1), a lysosomal marker well known to be overexpressed in MPS II; Rab11 (Ras-related protein Rab-11, Member RAS Oncogene Family), a small monomeric Ras-like GTPases involved in the regulation of the endomembrane trafficking and the endocytotic recycling.