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In Poland, 2-3 million Poles suffer from rare diseases. According to various estimates, the same number of Poles suffer from diabetes, but much more is said about diabetes. One of the rare diseases is Mucopolysaccharidosis (MPS).
It is a group of inherited, genetically determined metabolic diseases in the course of which there is an excessive accumulation of compounds called mucopolysaccharides in various tissues of the body. If you asked your GP about what mucopolysaccharidosis is, most of them would have trouble giving the right answer. Mucopolysaccharidosis is a rare metabolic disease with a complicated diagnostic process. Therefore, it happens that parents with a child suffering from mucopolysaccharidosis live in ignorance for years. It is possible that more children will be born during this time, and the risk of having another sick child is 25%.
Hunter’s syndrome
Mucopolysaccharidosis type II, also called Hunter’s syndrome, unlike other types of MPS, is inherited in conjunction with sex chromosomes. Boys, rarely girls, suffer from this disease. This is because the gene whose mutation causes this disease is located on the X chromosome. So if a boy receives the mutated X gene from his mother, he cannot have his “healthy” counterpart from his father who passed him on the Y chromosome. Girls are while carriers – usually asymptomatic, therefore in families with children affected by Hunter’s disease it is advisable to perform molecular analysis in women.
Morbidity and symptoms
The prevalence of MPS II (Hunter’s syndrome) in Poland is estimated at 1 in 100 – 0000 live births. According to the data of the Association of People with Mucopolysaccharidosis (MPS) and Rare Diseases, Hunter’s syndrome accounts for 170 percent. cases of MPS in Poland.
The disease affects the body’s ability to metabolize certain mucopolysaccharides, also known as glycosaminoglycans. In Hunter’s syndrome, mucopolysaccharides build up in the cells of the body because the enzyme idursulfase (I2S) is not working properly or is not present at all. Their accumulation disrupts the functioning of some cells and organs of the body, leading to numerous serious symptoms, including: movement disorders and contractures in the joints that change the shape of the child, respiratory failure, diseases of the heart valves and left ventricular hypertrophy, kyphosis and scoliosis, frequent infections and inflammation lungs, enlargement of the liver and spleen, and mental retardation. Dimorphic changes are also typical of the disease: short stature, short neck, large head, thickened facial features, low hairline on the forehead, large tongue, deformation of the teeth, thick skin, coarse coarse hair, clumsiness, contracture of the joints of the hands (clawed hands) .
Diagnostics
Mucopolysaccharidosis can be diagnosed with a urine test, but the final diagnosis can only be made by enzymatic testing, i.e. determining which enzyme is malfunctioning. An additional method used in some cases, e.g. to determine the carrier status, is DNA analysis. Due to the rarity of the disease, GPs do not have the opportunity to gain appropriate experience in diagnosing the disease. Meanwhile, early diagnosis is crucial and allows for quick treatment, even before irreversible changes occur in the body. To make it possible, it is necessary to educate GPs in the field of diagnosing rare diseases.
Two clinical forms of Hunter
Type II mucopolysaccharidosis occurs in two forms: classic – type A, in which cognitive impairment and mental retardation progress over time, and type B, with a much milder course, where mental retardation is absent or moderate.
Treatment
So far, it is not possible to completely cure mucopolysaccharidosis (there is no so-called causal therapy). Attempts of the so-called “Gene therapy” has so far been unsuccessful. However, many procedures are used to alleviate the effects of the disease. Scientists are still looking for new methods.
Currently, enzyme replacement therapy is used to treat MPS II, which consists of direct intravenous administration of purified enzyme. This method significantly alleviates its symptoms and thus improves the patient’s condition.
Thanks to the positive decision of the Ministry of Health in Poland, enzyme treatment has been available under the drug program for patients with Hunter’s disease since 2008. Patients are qualified for the Program by the Coordination Team for Ultra Rare Diseases appointed by the President of the National Health Fund. Qualification for the program and verification of the effectiveness of treatment is based on the assessment of the clinical condition of the recipient and the assessment of the effectiveness of the therapy applied. Each patient qualified for the program has free access to the drug. At the moment, 16 patients are treated under the MPS Type II Drug Program.
Possible discontinuation of treatment leads to the loss of beneficial clinical effects and a rapid deterioration of the patient’s condition, so it is crucial to maintain it after starting therapy without losing what has been achieved thanks to it.
Rare diseases in Poland
Raising issues related to rare diseases is often overlooked due to their emotional and ethical dimensions, as well as the unpopular pharmacoeconomic aspect. However, the example of the Hunter syndrome treatment program shows that the Ministry of Health sees the need to protect patients not only in the areas resulting from the priorities of the National Health Program for 2007-2015, but also in other areas, including rare diseases.
The current management of the Ministry of Health declares its willingness to introduce changes to the legislation in the field of rare diseases, such as: creating a team for rare diseases at the Minister and a national plan for rare diseases, introducing the definition of rare and ultra-rare diseases and changes in the reimbursement of drugs for these diseases .