Overview
- Mucopolysaccharidoses (MPS) are lysosomal storage disorders due to enzyme deficiencies impairing degradation of glycosaminoglycans (GAGs), also known as mucopolysaccharides.
- GAGs are complex sugar molecules found in connective tissues, skin, cartilage, cornea, liver, spleen, and vascular tissues.
- Examples: Dermatan sulfate, heparan sulfate, keratan sulfate, chondroitin sulfate, hyaluronic acid.
- Most MPS disorders are autosomal recessive, except MPS II (Hunter syndrome), which is X-linked.
Classification and Enzyme Deficiencies
| MPS Type | Gene | Enzyme Deficiency |
|---|---|---|
| MPS I | IDUA | Alpha-L-iduronidase |
| MPS II | IDS | Iduronate-2-sulfatase |
| MPS IIIA-D | SGSH, NAGLU, HGSNAT, GNS | Various (Heparan sulfate breakdown) |
| MPS IVA | GALNS | N-acetylgalactosamine-6-sulfatase |
| MPS IVB | GLB1 | β-galactosidase |
| MPS VI | ARSB | Arylsulfatase B |
| MPS VII | GUSB | β-glucuronidase |
| MPS IX | HYAL1 | Hyaluronidase |