The direct cause of mucopolysaccharidosis is a mutation of one of the genes that is responsible for controlling the production of the relevant enzymes. As a result of a genetic error, the enzyme may not be formed or may be defective. The breakdown of mucopolysaccharides then does not take place in the body. In the process, a protein may be produced that does not break down mucopolysaccharides as it should, or is not capable of doing so at all.

Mucopolysaccharidosis is a disease that is inherited in an autosomal recessive manner (for a child to become ill, he or she must inherit an abnormal copy of the gene from both parents). If they inherit one abnormal copy of the gene and the other a normal copy, they are known as healthy carriers of the gene. She can pass it on to her offspring. The characteristic symptoms of mucopolysaccharidosis are thickening of the skin and subcutaneous tissue, bone lesions and deformities. The facial features of affected individuals are specifically thickened, accompanied by mucosal polyps, hearing loss, stiffening of the joints, inguinal hernia, joint stiffening and neurological symptoms. The patient is unable to function independently.

The diagnosis of mucoplisaccharidosis is reduced to the quantification of mucopolysaccharides in the urine and the determination of their types. In addition, identification of mutations (DNA analysis) is performed. Treatment of mucopolysaccharidosis is symptomatic - there is no cure for this disease.