mucopolysaccharidosis type V
Introduction
Introduction of mucopolysaccharid storage disease type V Mucopolysaccharidosis type V, also known as Scheie's syndrome, has been classified as a subtype of mucopolysaccharidosis type I, because the enzyme deficiency of this disease is the same as type I, both Genes are also genetically identical. The syndrome is characterized by normal intelligence, moderate skeletal changes, aortic valve disease, and nerve compression. basic knowledge Sickness ratio: 0.000001% Susceptible people: no specific population Mode of infection: non-infectious Complications: hepatomegaly, deafness, aortic regurgitation, neuritis
Cause
Mucin-polysaccharide storage disease type V etiology
(1) Causes of the disease
The cause of this disease is autosomal recessive inheritance.
(two) pathogenesis
The pathogenesis of this disease is a basic metabolic defect, which is the lack of aL-iduronidase in the patient. When normal, the enzyme hydrolyzes the aL-idurald bond. This chemical bond is found in both dermatan sulfate and acetyl sulfate. In heparin, the lack of this enzyme can cause the two mucopolysaccharide components to deposit excessively in the cells, thereby damaging the cell function.
Pathology: The pathological changes of this type are similar to MPSI in some aspects. Microscopic examination of liver tissue parenchyma cells and Kupffer cells contain a large number of vacuoles, increased spleen connective tissue, dystrophic periprosthetic chondrocytes, kidneys, lymph nodes The endocardium, heart valve and blood vessel wall contain large cells of inclusion body. The brain tissue neurons are normal, no glial degeneration, only some lipofuscin granules, which is significantly different from MPS type I, but gray matter. There is dystrophic infiltration of fatty chondrocytes in the connective tissue, and inclusion bodies and collagen fibers are abnormal in the skin, mucous membrane and conjunctiva.
Prevention
Mucopolysaccharide storage disease type V prevention
Glycogen accumulation disease is a group of children with disorders of hereditary glycogen metabolism. It is characterized by excessive accumulation of glycogen in the body tissue and difficulty in decomposition. It is rarely a metabolic disorder of glycogen, resulting in less glycogen storage in the body. The original cumulative disease is not a disease, but a group of diseases. There are 12 kinds of diseases currently identified. The clinical features are characterized by hypoglycemia. The organs involved are mainly liver, kidney and skeletal muscles. Chromosomal recessive inheritance, no gender differences, mostly in childhood, some patients to adults, the disease no longer develops, can maintain general health.
The patients are mainly due to the lack of certain enzymes that break down glycogen, such as glucose-6-phosphatase, -1,4 glucose chymase, phosphofructokinase, hepatic phosphorylation kinase and the like.
Parents of many patients marry close relatives, avoiding close relatives marriage is an important part of preventing this disease. Once glycogen accumulation is found, it is mainly to prevent and treat hypoglycemia, a small amount of meals, limit fat and total calories, limit physical activity, serum lactic acid The highest, should take sodium bicarbonate to prevent acidosis, corticosteroids, adrenaline, glucagon, etc. can help control hypoglycemia.
Complication
Mucopolysaccharidosis V-type complications Complications, hepatic cerebral aorta, aortic valve, incomplete neuritis
The disease can be complicated by liver enlargement, deafness, psychotic symptoms, aortic regurgitation or stenosis, neuritis, corneal opacity.
Symptom
Mucopolysaccharidosis type V symptoms common symptoms deafness sensory joints tonic edema carpal tunnel syndrome
The clinical symptoms are similar to those of MPS IH, but they are mild. The earliest appearance and main symptoms are progressive corneal opacity, retinitis pigmentosa, mild joint stiffness at 6-8 years old, claw-like hands, face, and volume. Mild and rough, wide mouth, hairy, no obvious dwarf, can have large liver, small spleen, can have deafness, normal intelligence, and some even smart, and some have symptoms of psychosis, due to collagen tissue compression nerves, often Carpal tunnel syndrome (sensory disturbance in the median nerve distribution area, finger edema, atrophy of the fish) occurs, and aortic regurgitation or stenosis may occur later.
Examine
Mucopolysaccharide storage disease type V examination
Only dermatan sulfate appears in the urine, and the heterochromatic particles in the blood leukocytes and bone marrow cells are absent or unclear.
X-ray examination.
The X-ray performance is similar to the I type, but it is much lighter, and the change appears later, and the gnome is rare.
Diagnosis
Diagnosis and diagnosis of mucopolysaccharidosis
This type of diagnosis is similar to type I, but there is no mental retardation, the age of onset is also late, and there is neuritis, corneal opacity is peripheral.
The differential diagnosis of this type is also the same as type I, and must be carefully identified with other types of mucopolysaccharidosis, especially the type IV of polysaccharide storage, and the achondroplasia is carefully identified (Table 1).
