MUCOPOLYSACCHARIDOSIS TYPE II

Mucopolysaccharidosis Type II - General Information

Mucopolysaccharidosis Type II or Hunter syndrome is an inherited medical disease that affects males who suffer from the difficulty to metabolize mucopolysaccharides. Some researches reveal the women could be affected too but there are a small number of cases. The males that are confronted with coarse facial features like abnormal curvature of the spine, short stature, a bigger head and nose than usual, an oversized liver or spleen, thickened lips or have problems in cardiac function, difficulty in breathing (ex: obstructive airway disease), the incapacity to walk normally may have this disorder.

Estimated to be 1 in 100,000 to 150,000 male births, this genetic disease is characterized  by the inactivity (partially or completely) of an enzyme called  iduro-nate-2-sulfatase. In order to function properly the body needs  this enzyme to break down  and replace the proteoglycans. When the human-body accomplishes the transformation of these parts of the extra cellular matrix it results mucopolysaccharides or GAG. Most important in Mucopolysaccharidosis Type II are heparan sulfate and dermatan sulfate. For the breakdown of these molecules, the lysosomal enzyme I2S is required. The persons that suffer from the Mucopolysaccharidosis Type II confront with an incomplete breaking down process of the mucopolysaccharides and that leads to an accumulation of these molecules so the heart, bones, nervous system or connective tissue will be affected. The Hunter syndrome has two forms: a mild form (MPSIIB) and a severe form (MPSIIA).This disease can be detected  when the child is only 2 years old. For the other form the external manifestations occur when the child is older than 10.

Mucopolysaccharidosis Type II –Symptoms

The symptoms that are generally triggered by this particular medical condition (Mucopolysaccharidosis Type II) are usually not  visible when the child is born, as they tend to appear after about one or two years of life. Worthy of notice is that the first symptoms of this disease are not very concerning because of the fact that they are common symptoms for this early age. The infections of the ears, stuffy nose or simple colds will not make you think that you little boy has this disease. In time, Mucopolysaccharidosis Type II causes growth retardation, an enlargement of the head, nose, liver or/and spleen (hepatoslenomegaly), short stature, short neck, abnormal curvature of the spine (kyphosis), the presence of ivory-colored on the arms and legs, partial hearing loss, hernias, problems in cardiac function (enlarged heart), dysfunctional heart valves, papilloedma, recurrent diarrhea, joint stiffness, defects in the patient’s normal ability to pick up tiny objects, aggressive behavior, frequent pneumonia, hyperactivity, mental retardation.

In order to find out what causes your unpleasant symptoms (whether you are suffering from this medical disorder or from any other known medical condition) the first step is to take a urine test for GAG. Because its results are not 100% secure your personal doctor will have to accurately measure I2S activity in white blood cells, serum or fibroblasts. If the symptoms of this disorder are mild, the persons affected may have a normal life. However, sadly, for the males who have the severe form of this disease the chance of living is small because they develop a form of mental retardation and they do not live more than 15 years.

Mucopolysaccharidosis Type II-Treatment

Early diagnosis of this medical condition is extremely important because the children who have Mucopolysaccharidosis Type II may be incorrectly diagnosed so the doctors will not be able to provide referral in order to begin the treatment. In addition, genetic counseling is generally recommended in the case of families who have a Mucopolysaccharidosis Type II history. One possible treatment for the Mucopolysaccharidosis Type II is based on the injections with Idursulfase .Discovered on July 24, 2006 this enzyme replacement called Elaprase is expected to improve the quality of life. Despite of the fact that this drug is extremely expensive ($300,000) this is not a cure for this disease. In addition, the persons allergic to idursulfase should not use this drug to avoid the appearance of the side effects of Hunter syndrome.

One of the effects of injecting this enzyme is the improvement of walking .The patients who received every week  during a year this treatment succeeded to cover a 35 meters distance in 6 minutes. That is a big achievement but still the patients were not cured. The Mucopolysaccharidosis Type II treatment side effects are hypersensitivity reactions that may be threatening for patients’ life. For example, a male who have respiratory disease may worsen it due to the infusions with Elaprase. Despite of the adverse reactions like arthralgia, pyrexia or headache, fever, uneven heartbeats, chest pain, pain in the arms, joint pain the treatment was not stopped. The persons who use this kind of treatment should be careful what vitamins, medication or drugs have taken and ask doctor permission in order to not having severe problems later. Another attempt in finding the treatment for this life limiting disease is bone marrow transplantation.16 children were tested but still 15 were continuing to suffer from mental retardation having the I.Q. below 50. Nevertheless, improvements in the aspect of their appearance were registered. Their coarse facial features begin to fade and the motion of the joints improved. However, this way of treatment is limited because of the small number of histocompatible donors.

Other therapies for this disorder rely on fibroblasts experiments that reveal that mucopolysaccharides normal catabolism can be realized with fibroblasts from the persons who have other MPS disorders. Resembling results have been achieved with lymphocytes. The specialists’ researches have good results and soon a cure will stop this disease to progress. When Mucopolysaccharidosis Type II is diagnosed in a male, the doctors inform the family of the patient which are the implications of this disease and the treatment options: enzyme-replacement therapy or hematopoietic stem-cell transplantation. In order to know the benefits and risks associated with each form of treatment the medical knowledge should be precisely revealed to the parents.