Maroteaux-Lamy syndrome is a rare childhood disease also known as mucopolysaccharidosis type VI, MPS VI, and polydystrophic dwarfism. It’s inherited, which means it’s passed down in families. If you have it, you’re born with a mutation in your ARSB gene. This can cause multiple health problems, some of them deadly. It can also cause skeletal deformities.
MPS VI is progressive, which means it gets worse over time. But the rate of that worsening varies from person to person.
There’s no cure for MPS VI. But treatment should begin as soon as it’s diagnosed, for better quality of life. One case of this disease is found in every 250,000 to 600,000 babies.
What Causes MPS VI?
Your ARSB gene usually tells your body to make proteins and produce an enzyme called arylsulfatase B, which removes large sugar molecules called glycosaminoglycans (GAGs). But in MPS VI, it stops that enzyme from working the way it should.
As your GAGs build up, your tissues and organs become inflamed, scarred, and enlarged. They eventually break down and waste away (atrophy). This can lead to serious physical issues and affect your appearance. It can also cause learning, memory, and behavior problems.
It’s important to note that eating sugar or sugary foods won’t cause or worsen MPS VI.
How Do You Inherit MPS VI?
You get it from a recessive gene from both of your parents.
According to research, it’s caused when both of your parents carry a mutated copy of the ARSB gene and pass it on to you. This is known as an autosomal recessive pattern. The chance of both carrier parents passing on this defective gene is 1 in 4 pregnancies.
If only one parent passes this mutated gene to you, you won’t have MPS VI but you’ll be a carrier. The chances of this are 2 in 4 pregnancies. Your chance of not inheriting the mutated ARSB gene at all when you have carrier parents is 1 in 4 pregnancies.
The risk of inheriting the defective ARSB gene is the same for males and females, research shows.
What Are Symptoms of MPS VI?
Unless it’s a severe case, your child won’t have any signs or symptoms at birth. But they’ll probably show up in early childhood.
MPS VI can have a wide range of symptoms. But when it starts, what symptoms it causes and how fast it progresses vary from child to child. Some common symptoms include:
- Breathing problems
- Walking problems by age 10
- Bone and joint malformation
- Corneal clouding
- Heart problems
- Rounded and heavy facial features
- Stiff joints
- Short stature
- Vision and hearing problems
- Delayed or absent puberty
How’s It Diagnosed?
MPS VI is usually diagnosed when a child begins to show physical symptoms during early childhood and through urine tests, blood tests, or enzyme tests.
To confirm the diagnosis, your doctor may order genetic tests to confirm an ARSB gene mutation.
If you have a family history of MPS VI, tell your doctor about it early on in your pregnancy. They can order prenatal genetic testing and screenings to check if your child is a carrier or has the mutated ARSB gene.
It’s also possible to screen newborns for MPS VI with a simple blood test. But policies on this differ from state to state. Check with your doctor to see if it’s available in your area.
How Do You Treat MPS VI?
There’s no known cure. But you can help manage some symptoms with medications. Start treatment as soon as possible after diagnosis. Your doctor will help you choose the best treatment, based on your symptoms and how severe your disease is.
Your treatment options may include:
- Enzyme replacement therapy. The FDA has approved marketing for galsulfase (Naglazyme) for MPS VI.
- A bone marrow transplant
- Surgeries to fix or relieve some physical symptoms
What’s the Outlook?
Life expectancy for MPS VI depends on how severe your disease is and the quality of your treatment. In severe cases, death may occur in early childhood or teen years.
Those with mild forms of MPS VI usually live into adulthood. But heart problems, breathing issues, and worsening tissue and organ damage might reduce your quality and length of life.