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Hunter syndrome is an inherited disease caused by a faulty gene.
Children with Hunter syndrome lack an enzyme called iduronate 2-sulfatase that the body needs to digest sugar. As a result, undigested sugar molecules build up in the body.
This causes progressive organ damage, especially to the brain and heart, and breathing problems.
The medical name for Hunter syndrome is mucopolysaccharidosis type II, or MPS II.
Doctors at the Center for Rare Disease Therapy at UPMC Children's Hospital of Pittsburgh will work with you and your child to:
Make an appointment for your child for MPS II care at 412-692-7273 or rarecare@chp.edu.
About 1 in 100,000 to 170,000 babies are born with MPS II.
It nearly always occurs in males. Females can carry the gene that causes MPS II.
Changes in the IDS gene cause MPS II.
This gene tells the body how to make the enzyme you need to break down sugar. If you can't break sugar down, the molecules build up and affect the body's organs.
The gene that causes Hunter syndrome is on the X chromosome.
Because males only have one X chromosome, one altered gene can cause the condition.
Females have two X chromosomes, meaning they need two copies of the faulty gene to get MPS II. This is why Hunter syndrome is very rare in females.
MPS II mostly affects boys, and symptoms often appear around age two.
Hunter syndrome symptoms include:
There are two types of Hunter syndrome: severe and mild.
For children with severe MPS II, the disease will progress more quickly.
By around age eight, they:
The disease progresses more slowly for children with the mild type of MPS II.
They typically don't have cognitive issues. But they will have heart and breathing issues that continue into adulthood.
A doctor who suspects Hunter syndrome will test a child's urine to see if there's a build-up of sugar molecules. They will also order a blood test to measure enzyme levels.
Testing a child's genes can confirm the MPS II diagnosis.
There is no cure for Hunter syndrome.
Enzyme replacement drugs may help some children. This type of medicine does the job of the missing enzyme.
A stem cell transplant can also help some children with MPS II. Transplant isn't an option for all children with MPS II, but your child's doctor may discuss it with you.
Some supportive techniques that may help kids with MPS II include:
Doctors may also suggest surgery to address certain symptoms. For instance, surgery to replace a damaged heart valve can extend a child's life.
If a doctor diagnosed your child with Hunter syndrome, we want you to know you're not alone. The Center for Rare Disease Therapy is here to help.
The Program for the Study of NDRD can often schedule a visit within one week.
To make an appointment for your child or refer a patient for MPS II care, contact us by:
Here's what you can expect when you come to us for your child's first consult.
You can expect your first visit to take from four hours to a few days. Your child will have a thorough exam from Dr. Rajan, the NDRD program director.
She will make or confirm a precise diagnosis and find out how much the disease has progressed.
Because we work as a team at the center, other doctors and staff might see your child during your visit.
These may include experts in:
During your visit, we'll talk with you about:
We'll discuss the details of stem cell transplant if we think it might be a good option for your child. We want to make sure you know what the transplant entails and how you may need to prepare.
By the end of your visit, you'll have a care plan tailored to your child's MPS II needs. We'll also schedule a follow-up visit in three months.
You'll meet our nurse practitioner, who can answer questions by phone or video call between visits.
Before you leave, feel free to ask us about your child's diagnosis, treatment, or anything else.
Dr. Escolar will meet with you during your visit to go over test results and explain the next steps for treatment.
You can also find your child's test results on MyCHP — Children's patient portal. MyCHP portal lets you manage your child's health online.
It's free to kids getting treatment at UPMC Children's Hospital and their parents or guardians.
A rare disease like MPS II affects the whole family.
At the Center for Rare Disease Therapy, every child we see receives a tailored treatment plan and family-centered care.
We treat each family member as our partner. The best care approach happens when we merge our MPS II knowledge with your insight into what's best for your child.
For an appointment, consult, or referral for a child diagnosed with Hunter syndrome, please contact us at:
Learn how families are finding hope through the Center for Rare Disease Therapy.
View our Rare Disease Center patient stories>>
Clinical Studies
A Global, Multi-Center, Long-Term, Observational Registry of Patients with Hunter Syndrome (Mucopolysaccharidosis Type II, MPS II)
Study of Potential Treatment-Responsive Biomarkers in Hunter Syndrome
Study to Determine the Safety, Pharmacokinetics, and Pharmacodynamics of DNL310 in Pediatric Subjects with Hunter Syndrome
Study to Evaluate the Safety, Tolerability, and Pharmacodynamics of RGX-121 in Pediatric Subjects with MPS II (Hunter Syndrome)
A Long-term Follow-up Study to Evaluate the Safety and Efficacy of RGX-121
Study of Reduced-Intensity Conditioning In Patients With Non-Malignant Disorders Undergoing Umbilical Cord, Bone Marrow, or Peripheral Blood Stem Cell Transplantation
*Original research initiated by investigators at UPMC Children’s Hospital of Pittsburgh.
Children's Hospital's main campus is located in the Lawrenceville neighborhood. Our main hospital address is:
UPMC Children’s Hospital of Pittsburgh One Children’s Hospital Way 4401 Penn Ave. Pittsburgh, PA 15224
In addition to the main hospital, Children's has many convenient locations in other neighborhoods throughout the greater Pittsburgh region.
With MyCHP, you can request appointments, review test results, and more.
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