Fucosidosis
Introduction
Introduction to fucoside storage disease Fucosidosis is a kind of mucopolysaccharidosis caused by -fucosidase deficiency. It is characterized by abnormal nervous system, repeated respiratory infection, mental retardation and heart disease. Polysaccharide urine. basic knowledge The proportion of illness: the incidence rate is about 0.0002% - 0.0005% Susceptible people: more common in children Mode of infection: non-infectious Complications: dyskinesia
Cause
Cause of fucoidosis
(1) Causes of the disease
Genetic defects, alpha-fucosidase deficiency in patients is the main cause of the disease.
(two) pathogenesis
The basic biochemical defect of this disease is the lack of a lysosomal hydrolase, -fucosidase, which is located at 2q24~q32. The brain, liver, kidney, lung and urine of the patient have enzyme deficiency. The sediment of liver and other tissues is a sugar fat containing fucose (tetrahexose and pentohexosylceramide with fucose as the terminal part), especially in the brain, which is the disease. Pathogenesis.
The disease is divided into infant type and adult type. The pathological changes of infant type are characterized by characteristic cytoplasmic inclusion bodies in hepatocytes and many vacuoles with a diameter of 0.5-5 m. The vacuoles are covered with a membrane, and some vacuoles contain transparent carbon water. The compound must be stained with periodic acid to reveal the vacuole content, and some of the vacuoles are filled with a hydrophilic circular structure consisting of a complex lipid-specific lamellar layer, cytoplasmic inclusion bodies. Also found in Kupffer cells, tissue cells, macrophages, renal epithelial cells, biliary epithelial cells, endothelial cells and cardiomyocytes, most cells contain many transparent vacuoles, as well as hydrophilic dense inclusions and Layer structure material deposition, in the brain tissue, white matter shows a large loss of macrophages and myelin, there are granular lipids in the perivascular space, in the gray matter, there are neurons lost, the remaining neurons contain a bread The transparent vacuole of the film, with a diameter of 0.8-2.4 m, contains small particles in a network and a small number of parallel layered structures, astrocytes, oligodendrocytes and capillaries. The skin cells also contain transparent vacuoles or dense hydrophilic network materials. In histochemistry, the inclusion bodies are weakly positive for PAS staining and alkaline staining without metachromatic.
Adult histological features are vascular keratinoma-like changes in the skin, vacuoles in fibroblasts, vacuoles in neuronal Schwann cells, myoepithelial cells, sweat gland secreting cells, and vascular endothelial cells, due to vacuoles in endothelial cells. Swelling of the dermal blood vessels can cause stenosis or occlusion of the lumen.
Prevention
Fucoside storage disease prevention
Marriage and birth guidance, efforts to reduce the incidence of genetic diseases in the population, improve the quality of the population, the usual measures include: premarital examination, genetic counseling, prenatal examination and early treatment of genetic diseases.
For example, for pituitary dwarf patients with growth hormone, hemophilia patients with anti-hemophilia protein (clotting factor), the corresponding immunoglobulin for genetically immunodeficient patients.
Complication
Fucosidosis storage complications Complications
The disease can be complicated by neurological symptoms, respiratory infections, low muscle tone, and adult type can be complicated by sexual intelligence and motor developmental disorders.
Symptom
Fucosidosis storage symptoms Symptoms Children's mental motor development abnormalities, splenomegaly, forehead and humerus, thoracic scoliosis, mental retardation
Schoonderwaldt et al (1980) classified the disease according to the age of symptoms, I, II, III, I, II type more than infants and young children, the symptoms are heavy, it is also called infant type, type III in adults, mild symptoms Also known as the adult type, the infant type can have obvious clinical features in the first year of age. It often shows recurrent respiratory infections, low muscle tone, excessive sweating and short stature, progressive intellectual and motor development retardation. It is the earliest performance. Since the age of 2, the children's neurological symptoms have been progressively aggravated, accompanied by frequent convulsions. Some children have mild mucopolysaccharidosis type I face, hepatosplenomegaly, heart enlargement, skin. Thickening, back and back bending, other children's face is more like mucopolysaccharidosis type I, showing forehead protrusion, eye gap is too wide, nose bridge collapse, thick lips and tongues and other ugly face, neurological symptoms are not obvious, The cornea is generally clear, and the deterioration of nervous system symptoms begins 6 months after birth and more than 10 years old.
The clinical manifestations of adults are similar to those of young children, but they are also different. Adults can have progressive intellectual and motor developmental disorders, growth retardation, muscle weakness and low muscle tone, rough face, no hepatosplenomegaly, no corneal opacity. In addition, its most characteristic manifestation is that the skin has diffuse vascular keratinoma, which is characterized by a needle-sized blue-brown bulge lesion, which is initially distributed in the abdomen and back, and can be extended to the upper and lower limbs, sometimes with skin sweatlessness. High heat and ventilation can occur.
Examine
Examination of fucosidosis storage disease
In the peripheral blood lymphocytes, there are vacuoles weakly positive in PAS staining. In sweat, the content of chloride and sodium is 3-9 times higher than that of normal people. There is no excessive mucopolysaccharide in the urine, but there are too many rocks. Oligosaccharide and disaccharide excretion of alginose, cell biochemical analysis of liver tissue biopsy showed alpha-fucosidase deficiency.
X-ray examination: multiple bone dysplasia, delayed osteophyte maturity, thickening of the skull, lateral curvature of the lower back, accompanied by lordosis, vertebral hypoplasia, anterior upper part of the vertebral body is a bird's beak.
Diagnosis
Diagnosis and identification of fucoidosis
According to clinical features, diffuse vascular keratoma lesions, laboratory tests and specific enzyme assays can be diagnosed.
In the differential diagnosis, attention should be paid to the identification of several other mucinous storage diseases.
