Mucopolysaccharidosis (MPS)

MPS IH (Hurler syndrome; 607014*)

MPS IS (Scheie syndrome; 607016*)

MPS IH/S (Hurler-Scheie syndrome; 607015*)

Alpha-L-iduronidase

Onset: In IH, first year

In IS, > 5 years

In IH/S, 3–8 years

Urine metabolites:

Clinical features: Corneal clouding, stiff joints, contractures, dysostosis multiplex, coarse facies, coarse hair, macroglossia, organomegaly, intellectual disability with regression, valvular heart disease, hearing and vision impairment, inguinal and umbilical hernia, sleep apnea, hydrocephalus

Treatment:

MPS II (Hunter syndrome; 309900*)

Iduronate sulfate sulfatase

Onset: 2–4 years

Urine metabolites:

Clinical features: Similar to Hurler syndrome but milder and no corneal clouding

In mild form, normal intelligence

In severe form, progressive intellectual and physical disability, death before age 15

Treatment:

MPS III (Sanfilippo syndrome)

Onset: 2–6 years

Urine metabolites:

Clinical features: Similar to Hurler syndrome but with severe intellectual disability and mild somatic manifestations

Treatment: Supportive care

Type IIIA (252900*)

Heparan N-sulfatase

Type IIIB (252920*)

Alpha-N-acetylglucosaminidase

Type IIIC (252930*)

Acetyl CoA:alpha-glucosaminide acetyltransferase

Type IIID (252940*)

N-acetylglucosaminine-6-sulfatase

MPS IV (Morquio syndrome)

Onset: 1–4 years

Urine metabolites: Keratin sulfate; in IVB, also chondroitin 6-sulfate

Clinical features: Similar to Hurler syndrome but with severe bone changes including odontoid hypoplasia; possibly normal intelligence

Treatment: Supportive care

Type IVA (253000*)

Galactosamine-6-sulfate sulfatase

Type IVB (253010*)

Beta-galactosidase

MPS VI (Maroteaux-Lamy syndrome; 253200*)

N-Acetylgalactosamine-4sulfatase (arylsulfatase B)

Onset: Variable but can be similar to Hurler syndrome

Urine metabolites: Dermatan sulfate

Clinical features: Similar to Hurler syndrome but normal intelligence

Treatment:

MPS VII (Sly syndrome; 253220*)

Beta-glucuronidase

Onset: 1–4 years

Urine metabolites: Dermatan sulfate, heparan sulfate, chondroitin 4-sulfate, chondroitin 6-sulfate

Clinical features: Similar to Hurler syndrome but greater variation in severity

Treatment: Supportive care, stem cell or bone marrow transplantation

Onset: 6 months

Urine metabolites: None

Clinical features: Bilateral soft-tissue periarticular masses, dysmorphic features, short stature, normal intelligence

Treatment: Not established