When the janitor enzyme doesn’t work
Hunter syndrome, or why an enzyme
Hunter Syndrome (Gunther) is a rare, life-threatening genetic disease resulting from a deficiency of enzymes that control the removal of toxins. This leads to the accumulation of protein-carbohydrate complexes and fats in the cells, i.e. accumulated toxins slowly poison the body. Gradually, the child’s bones become deformed and internal organs become inflamed. He is degrading and dying.
The medical name for this disease is mucopolysaccharidosis type II (mucopolysaccharidosis type II) or MPS II.
What is gargoyleism
Hunter syndrome is a hereditary disease, the type of inheritance is X-linked recessive (i.e., lesion occurs only in boys). The first signs of the disease appear in 2 to 4 years. Prior to this, expressed clinical manifestations were not observed, with the exception of noisy breathing in infants due to obstruction of the upper respiratory tract, repeated rhinitis, inguinal and umbilical hernias.
Over the age of 2 years, thickening of the nostrils, lips, tongue, joint stiffness, growth retardation appear. Common signs of the disease are thickened skin, a short neck, and rare teeth. The child’s face acquires gross features (gargoylery), a low gross voice appears, and frequent acute respiratory viral infections.
Baby becomes aggressive
At 3 to 4 years of age, there are impaired coordination of movements; the gait becomes awkward, children often fall when walking, behavior changes, and aggressiveness appears.
At an older age, deafness, joint stiffness and other bone changes occur, atypical pigment retinitis is detected, and a slight clouding of the cornea appears. Intelligence is preserved, but mental changes may be observed.
There are two variants of the disease, A and B. With option A, all symptoms are severe, the disease is severe, with mental retardation; death occurs before 15 years. With the option During the illness, the lung, mental retardation is slightly expressed or absent, patients often live up to 30 years. Typically, patients die from cardiovascular decompensation, which occurs at the age of 35-45 years.
With Hunter syndrome, differential diagnosis is made with another rare hereditary disease – with Hurler syndrome. And even a district doctor can do this. Hurler syndrome is characterized by clouding of the cornea, which never occurs with type II mucopolysaccharidosis, that is, Hunter syndrome. At the same time, most disorders of the nervous system and brain in these diseases coincide.
To confirm the diagnosis of Hunter syndrome, a laboratory analysis of urine is done for the presence of dermatan and heparan sulfate in it. An X-ray examination reveals multiple dysostosis (an anomaly in the development of skeleton bones that underlies familial inherited diseases of the skeletal system).
The janitor enzyme that cleanses the body
A specific treatment for Hunter syndrome has not been developed, although scientists are working on this problem. June 20, 2005 American pharmaceutical company Shire Human Genetic Therapies Inc. (Cambridge) announced the latest positive clinical trials using the drug Elaprase (Elaprase) for the treatment of patients with Hunter syndrome (Gunther). The company provided full study data at a medical meeting in the fall of 2005. In November 2005, Shire applied to the United States Food and Drug Administration (FDA) for drug registration, and in the summer of 2006, the FDA officially approved the production and distribution of Elaprasetm replacement therapy for type II mucopolysaccharidosis.
In late summer 2006, the drug was licensed in the United States, and in 2007 in Europe. It was registered in Russia in the spring of 2008.
Currently, this is the only drug in the world that really improves the condition of patients with Hunter syndrome. The drug is a recombinant human enzyme called iduronate-2-sulfatase. And it is intended for enzyme replacement therapy, then this is the very enzyme “janitor” that cleanses the body. The mechanism for treating Hunter’s syndrome with Elapraz is similar to the mechanism for treating diabetes with insulin: the patient injected insulin – and then his body then works for some time practically correctly, and if he did not, then the person will inevitably die.
