Morquio syndrome

Morquio syndrome, or mucopolysaccharidosis type IV, is an inherited lysosomal storage disorder in which impaired keratan sulfate breakdown disrupts bone and connective-tissue development.

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Mucopolysaccharidosis type IVA: A form of Morquio syndrome caused by deficient N-acetylgalactosamine-6-sulfatase activity. This subtype accounts for most cases and links the disease to one specific enzyme deficiency.
Enzyme replacement therapy: Treatment that supplies a manufactured enzyme to compensate for deficient enzyme activity. Elosulfase alfa uses this approach for Morquio syndrome type IVA.
Mucopolysaccharidosis type I: A lysosomal storage disorder caused by deficient alpha-L-iduronidase and accumulation of dermatan and heparan sulfates. Unlike Morquio syndrome, it typically involves different stored molecules and often more prominent systemic disease.
Luis Morquio: A Uruguayan pediatrician who described a distinctive form of skeletal dysplasia in 1929. His report gave the syndrome its eponymous name.
Mucopolysaccharidosis type IVB: A form of Morquio syndrome caused by deficient beta-galactosidase activity. This subtype shows that the same storage disorder can result from a different enzyme defect.
Elosulfase alfa: A recombinant N-acetylgalactosamine-6-sulfatase used to treat mucopolysaccharidosis type IVA. It targets the enzyme deficiency underlying type IVA, though it does not reverse established skeletal changes.
Mucopolysaccharidosis type VI: A lysosomal storage disorder caused by deficient arylsulfatase B and accumulation of dermatan sulfate. Its skeletal manifestations can resemble Morquio syndrome, but the enzyme defect and stored substrate differ.
James Frederick Brailsford: A British radiologist who described a similar skeletal condition in 1929. His independent account is why the disorder is also called Morquio–Brailsford syndrome.
Keratan sulfate: A sulfated glycosaminoglycan found in cartilage, bone, and the cornea. Its impaired degradation leads to lysosomal accumulation in Morquio syndrome.
Urinary glycosaminoglycans: Glycosaminoglycans excreted in urine and measured as part of metabolic disease evaluation. Testing can support investigation of suspected Morquio syndrome, alongside specific biochemical and genetic tests.