Table 1. Classification of mucopolysaccharidosis (MPS).

Items	Subtypes	Deficient enzyme	Mutation of Gene	Locus	GAGs	Clinical features
MPS I	Hurler Syndrome	α-L-iduronidase	IDUA	4p16,3	HS, DS	Severe. Skeletal deformation, coarse facial features, hepatosplenomegaly, cardiac diseases, respiratory diseases, cognitive retardation, ocular disorders
	Hurler/Scheie Syndrome	α-L-iduronidase	IDUA	4p16,3	HS, DS	Intermediate.
	Scheie Syndrome	α-L-iduronidase	IDUA	4p16,3	HS, DS	Mild.
MPS II		iduronate-2-sulfatase	IDS	Xq28	HS, DS	Skeletal deformation, coarse facial features, hepatosplenomegaly, cardiac diseases, respiratory diseases, cognitive retardation, ocular disorders
MPS III	A	heparan-N-sulfatase	SGSH	17q25,3	HS	Cognitive retardation,
	B	α-N-acetyglucosaminidase	NAGLU	17q21.2	HS	behavioral problems
	C	α-glucosaminidase acetyltransferase	HGSNAT	8p11.21-p11.1	HS
	D	N-acetylglucosamin-6-sulfatase	GNS	12q14,3	HS
MPS IV	A	N-acetylgalactosamine-6-sulfate sulfatase	GALNS	16q24,3	KS, C6S	Skeletal deformation, corneal
	B	β-galactosidase	GLB1	3p22,3	KS	clouding,
MPS VI		N-acetylgalactosamine-4-sulfatse	ARSB	5q13-14	DS, C4S	Skeletal deformation, coarse facial features, may have normal intelligence
MPS VII		β-glucuronidase	GUSB	7q11,21	DS, HS, C4S, C6S	Hydrops fetalis
MPS IX		Hyaluronidase 1	HYAL1	3p21,3	HA	Periarticular masses, mild short stature

GAGs: glycosaminoglycans, HS: heparan sulfate, DS: dermatan sulfate, KS: keratan sulfate, C4S: chondroitin-4-sulfate, C6S: chondroitin-6-sulfate, HA: hyaluronic acid