Table 1.

Symptoms frequently observed in MPS I and MPS III patients and information regarding the different phenotypes and enzymatic subtypes

Disease	OMIM	Enzyme deficiency	Storage material	Main clinical features	Treatment	Prevalence
Mucopolysaccharidosis type 1 (MPS I)
MPS I – Hurler (MPS I-H)	607,014	α-L-iduronidase (IDUA)	Dermatan sulfate (DS) and heparan sulfate (HS)	Progressive neurocognitive decline, hernias, facial dysmorphisms, corneal clouding, stiff joints, dysostosis multiplex, cardiac problems and hepatosplenomegaly. Death in childhood if untreated.	HSCT	1.07/1.19 per 100.000 newborns
MPS I – Hurler-Scheie (MPS I-H/S)	607,015			Phenotype intermediate between MPS I-H and MPS I-S. Can present with or without neuronopathic disease.	HSCT or ERT
MPS I – Scheie (MPS I-S)	607,016			Corneal clouding, stiff joints, mild dysostosis multiplex. Normal intelligence en life expectancy.	ERT
Mucopolysaccharidosis type 3 (MPS III)
MPS IIIA	252,900	Heparan N-sulfatase (SGSH)	Heparan sulfate (HS)	Progressive neurocognitive decline, behavioral problems, sleep disturbances, progressive loss of motor functions. Death in second or third decade of life. Broad spectrum of disease severity.	Not available	1.52/1.89 per 100.000 newborns
MPS IIIB	252,920	N-acetyl-α-glucosaminidase (NAGLU)
MPS IIIC	252,930	Acetyl CoA:α-glucosaminide N-acetyltransferase (HGSNAT)
MPS IIID	252,940	N-acetylglucosamine 6-sulfatase (GNS)