Hunter Syndrome (MPS II)

Medically Reviewed by Nayana Ambardekar, MD on August 14, 2022
Written by Camille Peri
6 min read

Hunter syndrome, also called mucopolysaccharidosis II or MPS II, is a rare disease that's passed on in families. It mainly affects 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 them play, have friends, and do some of the things that other kids do, even though they may look different from their 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 their daughter, but the daughter won't get the disease unless they get the gene from their 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

They'll probably have these symptoms:

When a boy's brain is affected, it's likely they'll have:

  • Trouble thinking and learning by the time they are 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.

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 their urine
  • How active the "missing" protein is in their 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.

  • Will their symptoms change over time? If so, how?
  • What treatments are best for them 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 their 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
  • Breathing
  • Growth
  • 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 they're 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.

Focus on keeping your son healthy and giving them the chance to live a meaningful, rewarding life. Include them 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 them, be matter-of-fact about their condition. Talk about them as a person -- their interests, their curiosity, and their sunny personality, too. Let them know what their needs as well as their abilities are, and how they can help, if that's appropriate.

Activity. Start stretching and range-of-motion exercises early to keep their 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 them from the front, with hands out. Give them about an arm's length of space. It's OK to remind them to touch nice and not hit. But kids will be kids, so prepare them for stares and teasing with role-play and humor.

Extra help for learning. Help them learn as much as they can while their brain is working well. If they go to school, work with the staff to come up with an individualized education program (IEP) for them. They 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.

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.

If you are interested in more advanced reading on this topic, we’ve made content from our health professional site, Medscape, available to you on WebMD.

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