Skip to main content
Go to homepage

Print Page

Morquio A Syndrome

What Is Morquio A Syndrome?

Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) is one of a group of disorders called mucopolysaccharidosis (MPS) . In MPS, there’s either not enough of the enzyme that breaks down a type of sugar called glycosaminoglycans (or mucopolysaccharides) or none at all. The sugar builds up and leads to vision, hearing, bone, brain, and heart problems. Kids who do have some of the enzyme will have milder symptoms.

Medical care and treatments can help with symptoms of Morquio (MORE-kee-oh) A syndrome. And researchers are learning more all the time about ways to help people who have it live better.

What Are the Signs & Symptoms of Morquio A Syndrome?

Signs of Morquio A syndrome usually begin around a child’s first birthday. Morquio A syndrome is a skeletal dysplasia, a condition that affects the growth of cartilage and bone. This leads to:

  • short stature (height less than other people the same age)
  • curved spine (scoliosis or kyphosis)
  • “hypermobile” joints (joints that are more flexible than normal)
  • knock-knees (knees curve in)
  • a chest that juts out (pectus carinatum)
  • misshapen arms and legs
  • problems with teeth
  • unstable vertebrae (bones of the spine)
  • cord compression (when the vertebrae press on the spine)

Other signs include:

  • an enlarged liver
  • hearing problems
  • vision problems
  • heart problems

Morquio A syndrome is progressive. This means that it gets worse over time. Morquio A syndrome does not affect thinking and learning abilities.

What Problems Can Happen?

People with Morquio A syndrome can have unstable vertebrae. The vertebrae (bones that make up the spine) can slip and put pressure on the spinal cord (cord compression). Cord compression can come on slowly, starting with tiredness and weakness. Over time, it may lead to problems with walking and breathing.

What Causes Morquio A Syndrome?

A gene mutation (change) causes Morquio A syndrome. The mutation causes problems with cartilage and bone growth and other medical problems. It's is an inherited condition, and children who have it got one changed gene from each parent.

A genetic counselor can help families understand how Morquio A syndrome can run in families.

How Is Morquio A Syndrome Diagnosed?

To diagnose Morquio A syndrome, doctors do:

  • an exam
  • blood tests and urine (pee) tests to look at enzyme levels
  • genetic testing
  • imaging studies like X-rays and MRIs
  • an echocardiogram to check the heart
  • hearing tests and vision tests

How Is Morquio A Syndrome Treated?

A team of medical specialists cares for people with Morquio A syndrome. They can include:

Medical researchers are looking for ways to help people with Morquio A syndrome. Some treatments that are developing include:

  • weekly enzyme replacement therapy
  • gene therapy: to replace genes that make the needed enzymes
  • bone marrow transplant: to replace cells with missing or lacking enzyme with normal cells

How Can Parents Help?

The severity of Morquio A syndrome varies from person to person. There is no way to predict how someone will be affected. To help your child:

  • Teach your child about Morquio A syndrome.
  • Take your child to all medical visits.
  • Keep a written record of your child’s symptoms, treatments, and doctor visits.
  • Take care of yourself so you can care for your child.
  • Treat your child according to their age, not their size, and encourage others to do the same.
  • Answer questions as simply as possible. If someone asks what is wrong, for example, say, “Zara has a bone disorder.” Then, mention something special about your child. For example, “Zara has lots of interests. You should see her book collection.” This shows your child that many things make them special.
  • Find ways to adapt. For example, get a light switch extender and a stepstool so your child can turn the lights on and off. Encourage school staff to make similar changes to help your child, such as lower chairs and/or feet support.
  • Teach your child that being teased or bullied is not OK. If they're teased or bullied at school, work with your child, teachers, and administrators to end it.
  • Encourage your child to find a hobby or activity to enjoy. Help them try different activities like music, art, computers, writing, and photography.

What Else Should I Know?

The care team will work with you to give your child the best possible chance for a healthy future. Your child will need lifelong care, and at times this might feel overwhelming. Talk to anyone on the care team or a hospital social worker about resources that can help you and your child.

Support groups also can be helpful for kids and their families. Ask the care team for recommendations. You also can find support and more information online at:

Reviewed by: Shunji Tomatsu, MD, PhD
Date Reviewed: May 1, 2023

Lea este articulo en Español

What next?

By using this site, you consent to our use of cookies. To learn more, read our privacy policy.