What Is Hunter Syndrome (MPS II)?
Hunter syndrome, also called mucopolysaccharidosis II or MPS II, is a rare disease that's passed on in families. It usually affects only boys. Their bodies can't break down a kind of sugar that builds bones, skin, tendons, and other tissue. Those sugars build up in their cells and damage many parts of the body, including the brain. Exactly what happens is different for every person.
When your son has Hunter syndrome, there are things you can do to help him play, have friends, and do some of the things that other kids do, even though he may look different from his pals.
Although there is no cure for Hunter syndrome, there are ways to help manage it and live with the symptoms.
Boys with the disease can't make a certain protein because there's a problem with a small piece of their DNA, called a gene, that comes from their mother.
A dad with Hunter syndrome will pass the problem gene to his daughter, but she won't get the disease unless she gets the gene from her mom, too.
It's possible -- but very, very unlikely -- that someone could develop Hunter syndrome even though no one in their family going back has had it.
When Hunter syndrome affects the brain, which is about 75% of the time, symptoms usually show up between 18 months and 4 years of age. They start about 2 years later when the disease is milder.
Hunter syndrome usually affects how the boy looks:
- Large, round cheeks
- Broad nose
- Thick lips and a large tongue
- Bushy eyebrows
- Large head
- Slowed growth
- Thick, tough skin
- Short, broad hands with stiff, curled fingers
He'll probably have these symptoms:
- Joint problems that make it hard to move
- Numbness, weakness, and tingling in his hands
- A lot of coughs, colds, and sinus and throat infections
- Breathing problems, including pauses in breathing at night, or sleep apnea
- Hearing loss and ear infections
- Trouble walking and weak muscles
- Bowel problems, such as diarrhea
- Heart problems, including damaged heart valves
- Enlarged liver and spleen
- Bone thickening
When a boy's brain is affected, it's likely he'll have:
- Trouble thinking and learning by the time he is 2 to 4 years old
- Trouble talking
- Behavior problems such as a hard time sitting still or aggression
Kids who have Hunter syndrome are usually cheerful and affectionate, despite the problems it can cause.
Getting a Diagnosis
Doctors often have to rule out other medical conditions first. Your doctor may ask:
- What symptoms have you noticed?
- When did you first see them?
- Do they come and go?
- Does anything make them better? Or worse?
- Has anyone in your family had Hunter syndrome or another genetic disease?
If the doctors can't find another explanation for your son's symptoms, they'll test for Hunter syndrome by checking for:
- High levels of that certain sugar in his urine
- How active the "missing" protein is in his blood or skin cells
- The abnormal gene
After doctors are sure it's Hunter syndrome, it's a good idea to let extended family members know about the gene problem, too.
If you're a pregnant woman and you know you carry the gene or you already have a child with Hunter syndrome, you can find out whether the baby you're carrying is affected. Talk to your doctor about testing early in your pregnancy.
Questions for Your Doctor
- Will his symptoms change over time? If so, how?
- What treatments are best for him now? Is there a clinical trial that could help?
- Do these treatments have side effects? What can I do about them?
- How do we check his progress? Are there new symptoms I should watch for?
- How often do we need to see you?
- Are there other specialists we should see?
- If I have more children, are they likely to have this disease?
Early treatment may prevent some long-term damage.
Enzyme replacement therapy (ERT) can help slow the disease for boys with milder Hunter syndrome. It replaces the protein their body doesn't make. ERT can help improve:
- Walking, climbing stairs, and the ability to keep up in general
- Movement and stiff joints
- Hair and facial features
ERT is the first treatment for kids whose brains aren't affected. It doesn't slow the disease in the brain.
Bone marrow and umbilical cord blood transplants. These transplants bring cells into your child's body that can hopefully make the protein he's missing. The new cells come from either a bone marrow donor whose cells match your child's or the stem cells of umbilical cord blood from newborn babies.
Both of these treatments are high-risk. They're usually used only if other treatments aren't possible. They also haven't been shown to help when the brain is affected.
Research is under way to find effective treatments for boys with severe Hunter syndrome.
Treating the symptoms. Because so many different parts of your child's body can be affected, you'll probably need to see several doctors to help you manage the condition, including:
- Cardiologist: a heart specialist
- Ear, nose, and throat specialist
- Eye doctor
- Lung specialist
- Mental health professional
- Neurologist: works with the brain and nerves
- Speech therapist
Medication or surgery can ease some of the complications. Physical therapy can help with joint and movement issues. And occupational therapy can help you make changes at home and school to make it easier to get around and do things. Medications like melatonin may help with sleep.
Taking Care of Your Son
Focus on keeping your son healthy and giving him the chance to live a meaningful, rewarding life. Include him in family activities whenever it's safe.
Set the tone for others. Be positive. Keep an open mind about other people; they may not know what to say so they don't pry or offend or embarrass you. When someone asks about him, be matter-of-fact about his condition. Talk about him as a person -- his interests, his curiosity, and his sunny personality, too. Let them know what his needs as well as his abilities are, and how they can help, if that's appropriate.
Activity. Start stretching and range-of-motion exercises early to keep his joints flexible. Ask your physical therapist about ways to make exercises part of play. Choose large toys that are easy to grab and hold on to, that won't be damaged by chewing.
Encourage friendships. Talk to other kids (or their parents) about how to interact with your son. Walk up to him from the front, with hands out. Give him about an arm's length of space. It's OK to remind him to touch nice and not hit. But kids will be kids, so prepare him for stares and teasing with role-play and humor.
Extra help for learning. Help him learn as much as he can while his brain is working well. If he goes to school, work with the staff to come up with an individualized education program (IEP) for him. He may be eligible for one-on-one attention in the classroom or help for other issues, like hearing problems.
Take care of yourself, too. You'll do a better job caring for your child when you have people you can turn to to help out with caregiving tasks. Step back, and take a break to rest and recharge. Spend time nurturing your relationship with yourself and others you love. Remember, the whole family is affected by this disease. A counselor can help sort out feelings.
What to Expect
Some boys with less severe Hunter syndrome grow up and live long lives. They'll go through puberty like other teens and can have children. But heart disease and trouble breathing can still cause problems for them.
Kids with severe Hunter syndrome are less likely to reach adulthood. Their brains will slowly stop working, and eventually they'll need special care to make them comfortable.
Parents of other Hunter syndrome boys are a great resource for understanding what's going on, sharing your feelings, and getting ideas for how to live with the condition. You can find ways to enjoy the time that you have with your child.
The National MPS Society has more information about this disease. They can also help you connect with other families who are facing the same challenges.