<unk> , or Mucopolysaccharidosis III (MPS-III) is a rare genetic disease.  This lysosomal storage disorders is due to deficiency in one of the enzymes needed to breakdown the glycosaminoglycan heparan sulfate (which is found in the extra-cellular matrix and on cell surface glycoproteins).  Although undegraded heparan sulfate is the primary stored substrate, glycolipids such as gangliosides are also stored despite no genetic defect in the enzymes associated with their breakdown.
MPS-III has an incidence of approximately 1.89 per 100 000 live births.  Higher rates are found in certain populations such as the Ashkenazi Jews.  It is a rare disease.
Sanfilippo syndrome
Treacher Collins syndrome
Van der Woude syndrome
Tome-Brune-Fardeau syndrome
Klippel-Feil syndrome
Waardenburg syndrome
Turcot syndrome
Danon disease