Sly syndrome (mucopolysaccharidosis Type VII [MPS VII]), is the rarest mucopolysaccharidoses lysosomal storage diseases (National Organization for Rare Disorders [NORD], 2000), but has the widest effects. Types I (neonatal) and II (early onset) have severe effects, whereas Type III (late onset) has milder ones. In all types, deficiency of the enzyme beta-glucuronidase leads to an accumulation of complex carbohydrates in the brain. Type I is one of the few mucopolysaccharidoses that is present at birth.