What are the signs and symptoms of Hunter syndrome?

Hunter syndrome has a variety of signs and symptoms. Hunter syndrome can affect any part of the body. The symptoms of Hunter syndrome, and their progress and severity, are different in each person.

It is important to remember that many of these signs and symptoms are common in childhood, and it is the combination of them that may indicate Hunter syndrome. Not all patients will have all of the signs and symptoms, and they progress differently, so there is no typical patient experience.

There are two types of Hunter syndrome; these are known as neuronopathic (with cognitive impairment) and non-neuronopathic (without cognitive impairment). Both types experience signs and symptoms that affect the body, but the neuronopathic type also has symptoms that affect the brain and nervous system, meaning that behaviour and development are also affected. Nearly 7 out of 10 people with Hunter syndrome have the neuronopathic type of the disease.

Symptoms usually show between the ages of 2 and 4 years in the neuronopathic type, whereas the non-neuronopathic type generally presents symptoms later in childhood.




  • Hyperactivity
  • Obstinacy
  • Aggression


  • Cognitive decline
  • Seizures (may be ‘absence’ seizures, i.e. staring)


  • Particular facial features, such as a prominent brow, broad nose and thick lips
  • Large head
  • Sight problems
  • Large tongue
  • Irregularly shaped teeth


  • Joint stiffness, which may lead to restricted movement
  • Curled-in fingers
  • Carpal tunnel syndrome


  • Enlarged belly
  • Hernias (umbilical or inguinal)
  • Frequent or long-term diarrhoea


  • ‘Pebble skin’: white bumps that may form ridges
  • Short in height (from around 5 years of age)
  • History of frequent surgeries (e.g. carpal tunnel release, hernia repair, tympanostomy)


Delays in childhood development e.g.

  • delayed walking
  • delayed speech


Motor function problems


  • Frequent ear infections
  • Hearing loss
  • Long-term runny nose


Heart murmur or heart valvular disease


  • Frequent coughs and colds
  • Breathing problems, including noisy breathing and snoring

Hunter syndrome is a progressive disease

Children with Hunter syndrome often appear healthy at birth. The signs and symptoms of the condition become apparent as the glycosaminoglycans (GAGs) start to build up in the cells and organ systems of the body.

As the GAGs accumulate over time, the signs and symptoms of Hunter syndrome will progress. In neuronopathic Hunter syndrome, as well as the symptoms affecting the body progressing, symptoms affecting the brain and nervous system will also advance, meaning that there will be a decline in speech, learning and cognitive abilities.

Unfortunately, many symptoms of Hunter syndrome cannot be reversed once they have progressed to a certain point. However, it is important to remember that every child with Hunter syndrome is different, and there is no single disease course.

The symptoms affect life expectancy. The life expectancy for those with non-neuronopathic Hunter syndrome is early adulthood, however, some people can live into their fifth or sixth decade. The life expectancy for those who have neuronopathic Hunter syndrome tends to be within the second decade of life.

The progressive nature of the disease means that early diagnosis is essential, so that disease management can begin as soon as possible.

Aiden and AJ

Aiden was born a beautiful, healthy baby boy but he had frequent ear infections that we were told were typical. He had two sets of tubes put in his ears and then adenoids removed, when he was a year and a half old. He got colds a lot.

When he was about 2 years old, I noticed Aiden had speech delay. So, I got him into early intervention and his paediatrician suggested that it’s just something that kids go through, he’ll catch up. – Toni Ann, mother of Aiden and AJ

Hunter and Kingston

I have three sons. Hunter is my oldest, he’s 7 years old. He’s a livewire. From the very beginning he was sick all the time. We were in the hospital or the doctor’s office every month with high fevers because of ear infections. He had an umbilical hernia that never went away. I got pregnant with Kingston, when he was 6 months old. By that time, Hunter was just always sick. – Brittany, mother of Hunter and Kingston


My husband and I felt we were the luckiest people on earth when we actually held our little boy Silas in our arms. When Silas was around 6 months old, we noticed that the back of his head was becoming flatter and that he couldn’t hold his head up properly.

Silas always cried when he was laid down to play on his stomach. We saw an osteopath who gave us exercises that Silas didn’t like at all. The osteopath said she thought that Silas was maybe a bit ‘lazy’ as he didn’t invest much effort in trying to reach toys or in crawling. – View Silas' story

Learn more about how these families are living with Hunter syndrome