RARRES2 and mucopolysaccharidosis: Notable down-regulated genes in MPS compared to controls included RARRES2 (coding for Retinoic Acid Receptor Responder 2) (MPS IIIA and IIIB) and CXCL8 (coding for C-X-C Motif Chemokine Ligand 8) (MPS I and IIIA), while up-regulated genes compared to controls included MFGE8 (coding for Protein Containing Milk Fat Globule EGF and Factor V/VIII Domain) (MPS I and IIIA) and RPLP2 (coding for Ribosomal Protein Lateral Stalk Subunit P2) (MPS I and IIIB).