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Defining a Monster

     Explaining a medical condition is never easy, especially when it is a debilitating disease that takes the lives of young children much too soon.  Below you will find a concise introduction to what Hunter Syndrome is and a look into what it is like to experience this disease.  Although there are many facets to this condition and countless facts to share, we hope that what is included here gives you a general understanding of what this disease is and the effect it has on the lives of the children & families suffering from Hunter Syndrome.  If you have any questions about Hunter Syndrome that are not mentioned below, please feel free to contact us for more information.  

     Hunter Syndrome, also referred to as Mucopolysaccharidosis II or MPS II, is a progressively degenerative genetic disease in which a defective chromosome is missing an essential enzyme necessary for breaking down sugars in the body. Because this chemical decomposition is unable to happen, these cells continuously accumulate to toxic levels in the joints, muscles, and organs in the body causing stunted physical & mental growth, serious physical deformities, significant damage to the brain & organ function and eventually leads to premature death.  Currently there is no cure available for those affected by Hunter Syndrome.

What is Hunter Syndrome?
What Causes Hunter Syndrome?

     Hunter Syndrome has been classified in the medical field as an 'X-linked Recessive Disease'. This means that women are the carriers of the defective X chromosome and can unknowingly pass it on to their children; women who are carriers of MPS II are not affected by the disease and show no signs of the disorder.  Hunter Syndrome almost always occurs in males, although a few isolated cases have been found in females. Girls have a much lower risk of developing this disease because genetically they inherit two X chromosomes. If one of their X chromosomes is missing the enzyme, their second, 'normal' X chromosome can provide the functioning gene and prevent the disease from progressing. However, if the X chromosome of a male is defective and missing the necessary enyzme, there isn't another normal X chromosome to make up for the lacking enzyme and therefore the disease develops. Hunter Syndrome is an extremely rare condition, affecting 1 in 100,000 male births.

What are the Signs and Symptoms of Hunter Syndrome?

     Signs and symptoms of Hunter Syndrome are not present at birth and boys affected by this disease are born with no apparent idicators of it's presence.  Hunter Syndrome secretly hides out in the body and slowly starts to make it's appearance in the first few years of life, growing significantly worse over time at an expedited rate.  The debilitating effects of Hunter Syndrome affect both the body and the mind, causing several severe health complications that must be carefully addressed in order for life to continue.


      As these little boys grow, they begin to show physical signs that a problem is present.  Symptoms usually develop at 2 - 4 years of age and can include the following:


  • Noticeable skeletal irregularities like abnormal bone size or shape

  • An enlarged head with a shorter neck

  • A change in facial features, such as developing a protruding tongue, thickening in the lips, & a broad nose with flared nostrils 

  • Chubby, rosy cheeks

  • Thick, coarse hair and bushy eyebrows

  • A deep, hoarse voice

  • A bloated or inflated abdomen, indicating abnormal growth & enlarged internal organs

  • Stiffening of the joints in the body

  • Stunted physical growth

  • Frequent coughs, colds, and infections or constant runny nose

  • Delayed cognitive development, such as late walking, talking, & recognition

  • Decline / Regression on previously known skills

  • Abnormal aggressive behavior

     Early diagnosis of MPS II is absolutely critical for a child's life. The earlier MPS II is diagnosed and addressed, the sooner potential treatment options can be explored and developed.  Although Hunter Syndrome is a very rare and uncommon disease, it is important to remember that MPS II has a wide spectrum of severity so any concern for the symptoms mentioned above should be discussed with

your doctor or healthcare professional.

What Happens as Hunter Syndrome Develops?

     There are several complications that can occur as Hunter Syndrome progresses depending on the severity of the disease. These complications not only affect the skeletal system, but also affect the brain & nervous system, heart, lungs, joints, & connective tissue and can create respiratory, digestion & elimination complication.  Depending on where a child falls on the spectrum, some may have milder physical disabilities and slightly impaired intelligence or learning disabilities, while others with more severe cases develop more seriously debilitating physical deformities and have significantly impaired cognitive ability.

Brain & Nervous System Complications


     A vast variety of neurological problems may be present and continue to develop in children suffering from Hunter Syndrome.  Many of these complications are caused by an excess build-up of fluid around the brain, called hydrocephalus.  In individuals with severe cases of Hunter Syndrome, circulation of the fluid protecting the brain & spinal cord becomes blocked over time it is unable to be released back into the bloodstream. The blockage causes the build-up of fluid, resulting in increased pressure inside the head.  This compression within the skull can cause painful headaches, incontinence, and a delay or decline in developmental function.  Pressure from these fluids can also cause other complications that may affect a child's ability to see, ability to hear, ability to  understand, recognize and jeopardize other sensory organs.  Severe cases of Hunter Syndrome have been known to cause blindness, deafness, and the inability to speak & communicate.

Heart Complications


     Heart problems are very common in children with MPS II, and many of those affected have high blood pressure.  Complications can range from mild to severe, sometimes needing surgery to repair damage to the heart.  Endocardio Fibroelastosis (stiff heart), Cardiomyopathy (weak heart muscle),  and heart murmurs are conditions that can occur in children with severe cases of MPS II. 


     Endocarial Fibroelastosis is an extremely rare heart condition that affects infants and young children.  This condition is caused by the thickening of the supporitng connective tissues surrounding the heart chambers.  Life-threatening complications associated with endocardial fibroelastosis may develop, including an abnormally rapid heartbeat, irregular heart rhythms , and eventually congestive heart failure.


     In cardiomyopathy, the heart muscle becomes enlarged, thick, or rigid.  As cardiomyopathy worsens, the heart muscles becomes weaker and begin to lose their ability to function properly.  It is no longer efficiently pumping blood through the body and is unable to maintain a normal functioning rhythm. This overexertion of the heart muscle can lead to heart failure or arrhythmia. The weakening of the heart also can cause other severe complications, such as heart valve problems and cogestive heart failure.


      As blood passes from one chamber of the heart into another, our heart valves are designed to close tightly in order to stop blood from flowing back in the wrong direction. If a valve is weakened or damaged, it may not produce the force necessary to prevent blood from moving backward and create turbulence in the bloodstream, resulting in a heart murmur.  Most children with Hunter Syndrome suffer from damaged valves and weakend heart muscles. 

Lung & Respiratory Complications


     Abnormal growth in the nose, ears, throat, and chest cause several respiratory complications in children with Hunter Syndrome.  Poor facial bone growth and soft tissue storage in the throat leads to blockages in the airway, making it difficult to breathe properly.  Children with Hunter Syndrome suffer from chronic ear, sinus, and other respiratory infections and in some cases, pneumonia.  Enlarged tonsils and a narrowed trachea can further restrict airflow and create more complications.  Abnormal development of the chest cavity and enlarged organs in the abdomen also contribute to respiratory distress, as they restrict the amount of space the lungs have to expand while breathing. Depending on the severity of constriction in the airway, breathing may be extremely loud and noisy as the child struggles to maintain airflow.  Some children also suffer from sleep apnea, a condition in which breathing temporarily stops while sleeping.

Skeletal System Complications


    Childen with Hunter Syndrome see a tremendous impact on the growth and formation of the skeletal system.  This leads to significant bone problems (known as dysostosis multiplex) and can cause neurological complications if nerves become compressed by bone.  In addition to the physical changes explained above, children with Hunter Syndrome can also suffer from a wide range of other physical complications.  Poorly formed vertabrea can lead to instability in the spine, angular curves, and compression due to improper growth.  Over time, the joints of the body can become stiff and range of motion is drastically reduced to a minimum, sometimes elminating all range of motion completely.  Some joints have even been known to lock into position, needing careful massage and sometimes even surgery to regain the ability to move again.  

     Currently there is no definitive cure for Hunter Syndrome.  Treatment is available to help slow the effects this disease has on the body, but there are no treatment options that help improve brain and mental health.


     Enzyme replacement therapy has been beneficial in some cases, but this is a highly intrusive, very expensive form of treatment.  Enzyme replacement therapy uses a mad-made enzyme that is administered into the body through an IV.  This is a long, painful, weekly process that carries with it significant risks of adverse reactions, including anaphylactic shock.  There are few other forms of enzyme replacement therapy available, each having a slightly different method in which it is administered.  Treatment for Hunter Syndrome costs tens of thousands of dollars and guarantees nothing in the end.  Although these forms of treatment help slow the physical complications created within the body, enzyme replacement therapy options do not have any affect of the damage Hunter Syndrome does to the brain.


     But there is hope.  Dr. Douglas McCarty of Nationwide Children's Hospital believes that Gene Therapy could be the cure for Hunter Syndrome.  Gene Therapy identifies the defective gene that is associated with the disease and then designs a plan of action to replace the defective gene with new genetic material that will provide its originally intended functionality.  Current research has shown very promising results and hypothosizes success with human clinical trials.  As of right now, financial support is the only thing preventing Gene Therapy from moving forward into human clinical trials.  Ryan Our Lion has teamed up with other Hunter Syndrome foundations across the country to raise the funds necessary to make Gene Therapy a reality for children suffering from Hunter Syndrome.  Please join us in our fight for the cure and choose to donate today.  Every dollar we raise is one step closer to receiving the treatment necessary to save the lives of children suffering around the world.  

Is There A Cure For Hunter Syndrome?

What is Hunter Syndrome?

What is Hunter Syndrome?

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