HURLER SYNDROME
A child with Hurler Syndrome is missing an important protein to break down a sugary substance in the body. When the sugary substance isn’t broken down, it builds up and causes problems. It can damage the brain, heart, and other organs.
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Hurler Syndrome
Hurler syndrome, also known as mucopolysaccharidosis type IH (MPS I-H), is a rare, inherited disorder found in kids. It is a lysosomal storage condition where the cells fail to break down those sugar molecules due to insufficient enzymes. Therefore, an abnormal level of complex sugars accumulates in lysosomes in affected children. And since lysosomes are parts of your cells that are responsible for controlling the waste management of molecules, when excess molecules build up in lysosomes, the cells die quickly or can’t function properly.
Additionally, Hurler syndrome, a severe form of MPS 1, targets different organs and bones of children. It can be life-threatening while causing an interruption in their cognitive growth. Moreover, this autosomal recessive condition affects cognitive development causing joint and skeletal abnormalities, enlarged spleen and liver, and even respiratory issues.
Different Types of Mucopolysaccharidosis – Type I
The three types of Mucopolysaccharidosis type I (MPS I) include:
- Hurler syndrome
- Hurler-Scheie syndrome
- Scheie syndrome
Hurler Syndrome Causes
Hurler syndrome is a result of a mutation in the IDUA gene of a child, which creates lysosomal enzymes. It breaks down the molecular waste in cells and accumulates this toxic waste because of lacking enough enzymes. Therefore, the cells can’t carry out their functions properly. Since there is no way to eliminate that waste from the cells, the symptoms of this syndrome start appearing in children.
QUESTIONS AND ANSWERS
What is Hurler syndrome, and what are its hallmark symptoms?
- Hurler Syndrome: Hurler syndrome is a rare inherited metabolic disorder caused by a deficiency of the enzyme alpha-L-iduronidase. This deficiency leads to the accumulation of complex carbohydrates called glycosaminoglycans (GAGs) in various tissues and organs.
- Hallmark Symptoms: Children with Hurler syndrome typically exhibit a range of symptoms, including coarse facial features, enlarged liver and spleen, skeletal deformities, joint stiffness, heart and respiratory problems, hearing loss, vision issues, and developmental delays. Neurological symptoms can also occur, affecting cognitive and motor function.
How is Hurler syndrome diagnosed, and what is the treatment approach?
- Diagnosis: Hurler syndrome is diagnosed through a combination of clinical evaluation, genetic testing, and laboratory tests measuring GAG levels in the blood or urine. Prenatal testing may be available if there is a family history of the disorder.
- Treatment: The primary treatment for Hurler syndrome is hematopoietic stem cell transplantation (HSCT or bone marrow transplant). This procedure aims to replace the missing enzyme-producing cells with healthy ones to slow or halt the progression of the disease. Enzyme replacement therapy (ERT) with laronidase (Aldurazyme) can also help manage some of the symptoms by reducing GAG buildup. Supportive care, including physical therapy, occupational therapy, and speech therapy, is often necessary to address developmental and mobility issues.
What is the long-term outlook and life expectancy for children with Hurler syndrome?
- Long-Term Outlook: The long-term outlook for children with Hurler syndrome depends on several factors, including the age at which treatment begins, the severity of symptoms, and the success of transplantation or enzyme replacement therapy. Early diagnosis and intervention are crucial for the best possible outcomes.
- Life Expectancy: Without treatment, Hurler syndrome can lead to severe disabilities and a significantly shortened lifespan, often not extending beyond childhood. However, with early treatment and appropriate medical management, some children with Hurler syndrome have survived into adulthood and experienced improved quality of life. It’s important to note that while treatment can slow the progression of the disease, it may not completely eliminate all symptoms.
Hurler syndrome is a complex condition that requires specialized medical care, and families of children with this disorder should work closely with healthcare professionals experienced in the management of rare genetic disorders. Treatment and care plans should be individualized to address the specific needs and symptoms of each child with Hurler syndrome.
The doctors and surgeons at the Medical City Children’s Orthopedics and Spine Specialists treat children with Hurler Syndrome. We specialize in children and adolescents.
Symptoms of Hurler Syndrome
The symptoms of Hurler syndrome vary from one child to another. It can continue up to adolescence from early childhood. In addition, the signs distinguish it from the different levels of mucopolysaccharidosis type I (MPS 1). This includes progressive issues and developmental delays in case of how quickly your child learns or remembers any information.
But when the symptoms of Hurler syndrome are mild, the chances of affecting your kid’s intelligence are less. However, it can still cause:
- Problems with vision (glaucoma)
- Hearing loss
- Joint abnormalities, like tight muscles or carpal tunnel and any other disease
- Heart valve issues (cardiomyopathy)and respiratory infections where your child may experience difficulties in breathing
- Enlarged heart, liver, tissues, spleen, tonsils, and muscles
- Hernias
- Cerebrospinal fluid buildup around your kid’s brain (hydrocephalus)
Furthermore, in children with Hurler syndrome, some physical symptoms will appear during their first year.
- Excessive hair growth
- Incorrectly formed bones (dysostosis)
- Short stature
- The upper back of your child has a rounding curve, known as thoracic-lumbar kyphosis
How Is Hurler Syndrome Hereditary?
As mentioned earlier, Hurler syndrome is a hereditary lysosomal storage condition. Therefore, the chances are that a child can get it from his or her parents. But it’s not a result of anything a mother did during pregnancy. Instead, it can happen during the cell division process. Fertilized cell forms from the egg and the sperm in the reproductive organs. Genetic mutation can happen randomly during cell division, leaving the genetic code for your DNA part incomplete. Hence, the cells don’t have complete instructions on how to perform correctly. Thus, Hurler syndrome occurs!
Effects of Hurler Syndrome on Children
This syndrome can affect any child because it happens due to random genetic mutation. Also, when your family has a medical history of mucopolysaccharidosis type I (MPS I), the risks of Hurler syndrome in your child increase.
Research shows that Hurler syndrome can affect one child in every 100,000 newborns, whether it’s a boy or a girl. In addition, the mild form of mucopolysaccharidosis type I (MPS I) occurs in one of 500,000 newly born children. This condition can affect different aspects of their body system, like physical characteristics.
However, these symptoms can vary for every child. For example, it can be an enlarged head for some while unique facial features for many such as a large forehead or eyes with wide space. Also, these physical characteristics can have an effect on the bone growth of your children, which can cause short stature.
Hurler syndrome can affect even the internal organs of a child, especially the lungs and heart. Moreover, a kid with this condition can have sinus and pulmonary infections and recurrent ear and breathing issues. But early diagnosis and proper treatment can improve your child’s condition. However, if you plan to conceive and don’t want such a risk of having a newborn with Hurler syndrome, contact your doctor about genetic testing!
Diagnosis
The best way to diagnose the symptoms of Hurler syndrome in your child when you are pregnant is prenatal screening tests. These tests identify if your baby’s DNA has any genetic abnormalities. Also, once your baby is born, the doctors diagnose this syndrome through a physical examination to determine the enzyme activity and symptoms. The healthcare providers can even do additional tests like an echocardiogram of your child’s heart or bone X-ray, including urine and blood tests to confirm it. In fact, they may ask about your family’s medical history and ensure whether any member has a mucopolysaccharidosis condition. In that case, it can be inherited in your baby.
Hurler Syndrome Treatments
This process generally focuses on managing and preventing the symptoms of Hurler syndrome. The treatment options are different based on the severity of the child’s condition. It is encouraging to know that scientists continue to research new therapeutic medicines and therapies. Parents should take their child to specialists who are aware of Hurler Syndrome and the latest FDA-approved treatment methods to manage the condition. This process can give your children a prolonged life expectancy even with severe symptoms.
Furthermore, some other treatment options for Hurler syndrome are here as well:
- Consuming prescribed medicines to reduce pain related to this condition
- Physical or speech therapy
- Surgery to improve the symptoms, like replacing cornea and heart valves or repairing hernias and bone growth abnormalities
- Use hearing aids
However, complications during the treatment may occur due to the anesthetic the healthcare providers give during the surgery. It happens especially when your children have breathing difficulties or tight tissues, muscles, and joints. Moreover, the effectiveness of the treatment depends on the early diagnosis of the syndrome. For instance, if your child has problems with cognitive development, some of the treatment methodologies may not work to their full potential!
So, talk to our doctors about such probable complications before the treatment starts.
Hurler Syndrome Prevention
When you plan to be pregnant, you can reduce the risk of having a baby with Hurler syndrome by consulting a doctor about genetic testing. However since it is hereditary, you cannot prevent it if a random genetic mutation happens. Contrarily, if you already have a child with this syndrome, early diagnosis, and treatments are the only way to prolong his or her life. Otherwise, you may expect a short life for your child, around ten years, because of severe conditions that target respiratory organs.
Also, children with mild or intermediate Hurler syndrome can live up to early twenty or thirty with treatment. But in this case, beginning an early treatment can give your kids a normal lifespan.
When You Should See Your Child a Doctor
If you see your child having problems with hearing or seeing or achieving developmental milestones, these can be symptoms of Hurler syndrome. Therefore, you should contact a healthcare provider like Medical City Children’s Orthopedics and Spine Specialists with offices in Arlington, Dallas, Flower Mound, Frisco, and McKinney, TX for diagnosis as early as possible.
Final Thoughts
After hearing that your child has a short life expectancy, you may feel devastated. And since there is no cure for Hurler syndrome, you should consult with our specialists about the various FDA-approved treatments that are available today that will improve the severity of symptoms and prolong life.
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Footnote:
Genetic and Rare Diseases Information Center: Hurler Syndrome
Call 214-556-0590 to make an appointment.
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