Hurler syndrome

Hurler syndrome is a disease you’re born with that affects metabolism. Metabolism is the process of breaking down food into energy. In Hurler syndrome, the body lacks an essential enzyme needed to break down a specific sugar-based substance. Without this enzyme, the substance builds up in the body and causes damage to the brain, heart, and other organs.

Signs of Hurler syndrome may appear at birth, but in some cases, symptoms develop between the ages of 2 and 8. Children with Hurler syndrome often experience:

• Slower growth compared to peers
• Hearing problems
• Learning difficulties
• Movement challenges

Early diagnosis and treatment are critical to managing the disease and preventing further damage.

A blood or marrow transplant (BMT), also known as a bone marrow or blood stem cell transplant, is a treatment that can stop Hurler syndrome from causing additional damage. It works by replacing unhealthy blood-forming cells with healthy ones that contain the missing enzyme. With these healthy cells, the body can break down the sugar-based substance and prevent further organ damage. However, a transplant cannot reverse damage that has already occurred.

An allogeneic transplant is the most common type of transplant for Hurler syndrome, which uses healthy blood-forming cells donated by another person. These healthy cells can come from a:

• Family member
• Unrelated donor
• Umbilical cord blood

The transplant process for Hurler syndrome involves three main stages: preparation, transplant and recovery. Each step is essential for replacing unhealthy blood-forming cells with healthy ones to stop further damage caused by the disease.

1. Preparation: The process starts with chemotherapy (and sometimes radiation) to destroy the unhealthy cells in the bone marrow.
2. Transplant: Healthy blood-forming cells from a donor are infused into the child’s bloodstream through an intravenous (IV) catheter. These cells travel to the bones, where they begin producing healthy blood cells.
3. Recovery: After the transplant, recovery can take several months, both in the hospital and at home. The transplant team will closely monitor for complications and provide support to ensure the child’s safety.

Most children have a better chance of a cure if they have a transplant soon after diagnosis. Your child should see a transplant doctor as soon as your child is diagnosed. Early intervention can prevent further damage and improve your child’s long-term prognosis.

At the first appointment, the transplant doctor will:

• Review your child’s medical history
• Discuss treatment options specific to your child’s condition
• Explain the risks and benefits of a transplant
• Recommend the best time to begin the transplant process
• Begin a donor search to access healthy cells

Ask questions so you understand your treatment options and can make decisions that are best for your child. Questions you may want to ask include:

• What are the chances transplant will stop the Hurler syndrome from causing more damage?
• What are the possible side effects of transplant? How can they be reduced?
• How might my child’s quality of life change over time, with or without transplant?