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Mucopolysaccharidosis type IVA (MPS IVA), also known as Morquio A syndrome, is a rare inherited disease that affects major organ systems in the body. People born with Morquio A can’t break down glycosaminoglycans (GAGs) molecules because their bodies don’t make enough of an enzyme, or protein, called N-acetylgalactosamine-6 sulfatase (GALNS). This enzyme breaks down or recycles materials the body can’t use. When the body doesn’t produce enough of the enzyme, GAGs build up in tissues, bones, and major organs. GAGs cause serious problems, including heart disease, skeletal abnormalities, vision and hearing loss, difficulty breathing, and early death.

Signs and Symptoms

When GAGs build up in the bodies of people with Morquio A, the results can potentially be severe. People with Morquio A have physical problems and organ complications that can lead to difficulties performing daily activities, and reduced endurance may cause them to need walking aids or wheelchairs. The signs and symptoms of Morquio A are not usually easy to see at birth, however, by the time the child is 2 or 3 years old, enough GAGs have built up in the child’s body to start causing noticeable problems. The signs and symptoms of Morquio A can affect many different parts of the body and frequently include heart, lung, visual, hearing, and dental complications, in addition to the skeletal problems that are typically present in people with Morquio A syndrome.

Skeletal symptoms

  • Skeletal deformities
  • Short trunk
  • Weakness in the neck
  • Spinal cord compression
  • Knock knees
  • Overly flexible joints
  • Abnormal walk
  • Scoliosis
  • Chest deformities

Nonskeletal symptoms

  • Breathing problems
  • Heart valve problems
  • Muscle weakness
  • Eye problems
  • Hearing loss
  • Dental problems
  • Enlarged liver
  • Enlarged spleen
  • Limited endurance

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