Table 1 Summary of traditional MPS types, characteristics, and available treatments
Name | Enzyme deficient | Gene | Accumulated substrate | Disease onset | Major symptoms | Currently available treatments |
|---|---|---|---|---|---|---|
MPS I (Hurler/Scheie syndrome) | α-l-iduronidase | IDUA | Heparan sulfate Dermatan sulfate | Ages 1–15 | Growth retardation, coarse face, hepatosplenomegaly, kyphosis, corneal clouding, heart valve abnormalities, hydrocephalus, hearing loss | ERT (IV) Eisengart et al., 2018; Shapiro et al., 2015; Wraith et al., 2007 [127–129] HSCT Aldenhoven et al., 2015; Shapiro et al., 2015; Eisengart et al., 2018 [127, 128, 130] |
Hurler syndrome | Ages 1–2 | Severe | ||||
Hurler/Scheie syndrome | Ages 1–5 | Intermediate | ||||
Scheie syndrome | Ages 3–15 | Mild | ||||
MPS II (Hunter syndrome) | Iduronidase-2-sulfate | IDS | Heparan sulfate Dermatan sulfate | Ages 1–5 | Mental/growth retardation, coarse face, hepatomegaly, kyphosis, hernias, skin abnormalities, heart valve abnormalities, spinal stenosis | ERT (IV) Kim et al., 2017 [131] |
MPS III (Sanfilippo syndrome) | Heparan sulfate | Ages 1–4 | Mental retardation, CNS degeneration, development delay, coarse face, hepatosplenomegaly, seizures, hyperactivity, aggression | No approved treatment Kong et al., 2020 [132] | ||
IIIA | Heparan-N-sulfatase | SGSH | ||||
IIIB | α-N-acetylglucosamine 6-sulfatase | NAGLU | ||||
IIIC | α-glucosaminidase acetyltransferase | HGSNAT | ||||
IIID | N-acetylglucosamine 6-sulfatase | GNS | ||||
MPS IV (Morquio syndrome) | Keratan sulfate | Ages 2–4 | Coarse face, skeletal abnormalities, hearing loss, corneal clouding | ─ | ||
IVA | N-Acetylgalactoasmine-6-sulfate sulfatase | GALNS | Severe | ERT (IV) & HSCT Sawamoto et al., 2020 [133] | ||
IVB | β-galactosidase | GLB1 | Mild | ─ | ||
MPS VI (Maroteaux-Lamy syndrome) | N-acetylgalactosamine 4-sulfatase | ARSB | Dermatan sulfate | Ages 2–5 | Coarse face, umbilical hernia, hepatosplenomegaly, corneal clouding, skeletal abnormalities | ERT (IV) D'Avanzo et al., 2021 [134] HSCT Turbeville et al., 2011 [135] |
MPS VII (Sly syndrome) | β-glucuronidase | GUSB | Heparan sulfate Dermatan sulfate | Birth-year 1 | Hydrops fetalis, Hernias, short stature, heart disease, coarse face, hydrocephalus, corneal clouding, hepatosplenomegaly, cognitive impairment | ERT (IV) Parini and Deodato, 2020 [40] HSCT Taylor et al., 2019 [136] |
MPS IX (Natowicz syndrome) | Hyaluronidase | HYAL1 | Hyaluronan | Birth-year 1 | Cleft palate, development of soft tissue masses, short stature, hyperplasia | ─ |
MPS X | Glucuronate-2-sulfatase (Arylsulfatase K) | ARSK | Heparan sulfate Chondroitin sulfate Dermatan sulfate | ─ | Coarse facial features; Skeletal, vision, and cardiac abnormalities | ─ |