Mucopolysaccharidosis (MPS) is a rarely diagnosed metabolic disease with a genetic basis, which damages many organs, and hence - their failure. What are the causes and symptoms of mucopolysaccharidosis? How is the treatment of patients struggling with this disease?
Mucopolysaccharidosis( MPS ) is a rarelysosomal storage disease , a genetically determined disease, in which, due to a defect or lack of activity of one of the enzymes (proteins), various substances accumulate in the lysosomes. The essence of mucopolysaccharidosis is the deficiency or defect of enzymes that are responsible for the breakdown of mucopolysaccharides (components of connective tissue) into individual small molecules. As a consequence, they accumulate in organs, which are then damaged.
Mucopolysaharidosis belongs to the group of rare diseases because it occurs once in 100,000 births.
There are several types of mucopolysaccharidosis, each caused by a different enzyme deficiency:
- type I - Hurler's disease (formerly type V)
- type II - Hunter syndrome
- type III - Sanfilippo syndrome
- type IV - Morquio team
- type VI - Maroteaux-Lamy syndrome
- type VII - Sly's syndrome
Mucopolysaccharidosis - causes
The cause of the disease is a mutation in the gene that controls the production of the right enzymes. Due to a genetic error, the enzyme that breaks down mucopolysaccharides may not be produced, or a protein may be produced that is unable to break down mucopolysaccharides, or does not do it as it should.
Mucopolysaccharidosis - inheritance
Mucopolysaccharidoses are inherited mainly in an autosomal recessive manner. This means that in order for a child to fall ill, they must receive one altered copy of the same gene from each parent. If a child inherits one altered copy and one normal copy, it will be a he althy carrier because the presence of the correct copy compensates for the presence of the defective one (this is the case in most cases). Being a carrier means you are not affected, but the faulty gene can be passed on to your offspring.
The exception is mucopolysaccharidosis type II (Hunter's disease), the inheritance ofis linked to the X chromosome.
Mucopolysaccharidosis - symptoms
Thickening of the skin and subcutaneous tissue and, as a result, thickening of facial features (the so-called grotesque face), and bone changes causing deformities and motor disability, are symptoms characteristic of mucopolysaccharidosis. In addition, the following usually appear:
- umbilical hernias
- inguinal hernia
- mucosal polyps
- hearing loss
- joint stiffening
- neurological symptoms
Over time, excessive mobility, corneal clouding and convulsions may also appear. The disease can also lead to a delay in physical development (weight and height deficiency).
Mucopolysaccharidosis - diagnosis
In order to diagnose the disease, it is necessary to perform a test that consists in the quantification of mucopolysaccharides in the urine (in the case of mucopolysaccharidosis they are secreted in excess) and determine their type.
An additional diagnostic method is the identification of mutations, i.e. DNA analysis.
ImportantMucopolysaccharidosis can also be diagnosed thanks to prenatal tests, performed at 14-16 weeks of pregnancy. Currently, the law in Poland allows abortion in the event that the fetus is diagnosed with mucopolysaccharidosis.
Mucopolysaccharidosis - treatment
Causal treatment of mucopolysaccharidosis, like any genetic disease, is not possible. Therefore, the goal of therapy is to alleviate troublesome symptoms. In some types of disease, this goal is achieved through bone marrow transplantation. In other cases, an effective method is the so-called enzyme replacement therapy, i.e. direct intravenous administration of purified enzyme. Unfortunately, this method is very expensive.
One of the first symptoms of mucopolysaccharidosis is the umbilical and inguinal hernia, therefore the surgeon's intervention may be necessary in infancy. In the next stages of the patient's life, gymnastics is needed to avoid stiffening of the joints. If the patient is struggling with diarrhea, the doctor may order medications to weaken bowel movement. The problem may also be excessive excitability and mobility of children. Sedation may then be necessary.
More information can be found on the website of the Association of People with Mucopolysaccharidosis (MPS) and Rare Diseases.