A disorder of proteoglycan catabolism caused by congenital defects in proteoglycan degrading enzymes. It is characterized by excessive accumulation and excretion of oligosaccharides. Patients with mucopolysaccharidosis type I(H) have an ugly face, resembling the monster on the gutter (Cheng C) under the eaves of an ancient Chinese building, so it is also known as Cheng C disease. Patients are more male than female, and are mostly seen in the offspring of inbred marriages, and mostly have a family history. There is no specific treatment, only symptomatic and supportive therapy. The prognosis varies depending on the type of enzyme defect. In general, children with Mucopolysaccharidoses develop after 1 year of life and die around 10 years of age, but some patients can survive until they are more than 50 years old. Mucopolysaccharidosis (MPS) is a genetic disorder characterized by disorders of mucopolysaccharide metabolism, caused by mutations in the activation of one or more lysosomal enzymes necessary for mucopolysaccharide degradation, resulting in skeletal, visceral, corneal, and intellectual abnormalities. Mucopolysaccharide is distributed in the matrix of connective tissue, and it is an important component of cartilage, periosteum, vascular wall and subcutaneous tissue. Under pathological conditions, abnormal mucopolysaccharide can be deposited in various tissues and organs in the body, such as cartilage, fascia, tendons, blood vessels, heart valves, muscles, osteocytes, chondrocytes, reticuloendothelial system and subcutaneous tissue. In addition, there are similar changes in liver, kidney, and ganglion cells. Skeletal lesions may be associated with impaired normal thickening of epiphyseal plate chondrocytes. Patients have significantly increased urinary mucopolysaccharide excretion and are classified into seven types according to their biochemical properties of urinary mucopolysaccharide. 1, Mucopolysaccharidosis type I is the prototype of mucopolysaccharidosis and the most serious one. Lipids are deposited in the central nervous system and other organs. It is autosomal recessive. It is characterized by short stature, large head, ugly face, widened spacing between eyes, collapsed nasal bridge, lip ectropion, tongue protrusion, sluggish expression, cloudy cornea, mental retardation, posterior spine protrusion, abdominal bulge, significant increase of dermatopoietin sulfate and acetyl heparin sulfate in urine, heterochromatic particles (Reilly vesicles) can be found in leukocytes and bone marrow cells, and most of the patients are day folded before 20 years old. 2, mucopolysaccharidosis type II is similar to type I, but the degree of light and slow progress, for the companion recessive inheritance. Clinical and X-ray manifestations as type I. Patients can usually live to adulthood. 3.Mucopolysaccharidosis type III is different from the first two and is autosomal recessive. It is characterized by progressive mental retardation, which is severe at the age of about 10 years. Its manifestation is type I and II, but it is lighter, and some faces are not changed. Excessive acetyl heparan sulfate is excreted in the urine. Mucopolysaccharidosis type IV (Morquio disease) is autosomal recessive, about 1/3 have a family history, slightly more males, and skeletal changes do not appear until walking. The typical presentation is dwarfism with lower back hunch, knee valgus, and flat feet. When standing, the hips and knees are bent in a semi-squatting position. The head is stretched forward and sinks between the high shoulders, the nose is collapsed, the hands and feet are deformed, and corneal clouding and aortic atresia may appear around the age of 10. Most of them die before the age of 20 years, but mental retardation is not obvious. The urinary mucopolysaccharide is increased excretion of keratan sulfate, normal is 0.1mg/L, but the patient may have up to 45mg/L and Reilly vesicles in the leukocytes. the most prominent thing on the x-ray is the consistent flattened vertebrae with a tongue-like protrusion in the center of the vertebrae. In addition, the canalicular bone is thick and short, the epiphysis is widened, the pelvis is deformed, the femoral head is flattened, and the epiphysis is fragmented. Cervical 1-2 subluxation may result from hypoplasia of the cervical 2 dentate process. Rarely live beyond 20 years of age. 5.Mucopolysaccharidosis type V. This type is similar to type I. It has moderate or above intelligence and can live to middle age. 6.Mucopolysaccharidosis type VI The clinical and X-ray manifestations of this disease are similar to type I or II, and the biological changes are similar to type V. 7, mucopolysaccharidosis type VII (β glucosidase deficiency) is rare, and patients often have hepatosplenomegaly, multiple bone dysplasia and mental retardation. Treatment options There is generally no drug treatment for this disease. Specific treatment is bone marrow transplantation to replace the enzyme deficiency in all types of mucopolysaccharidoses, and enzyme replacement and gene therapy are under investigation. Disease prevention The disease is mostly autosomal recessive and increased mucopolysaccharides are found in fibroblast cultures of patients and their heterozygous relatives. For those with a positive family history, pregnant women can have an amniotic fluid examination at 16-20 weeks of gestation to determine the mucopolysaccharide content of the amniotic fluid, or an amniotic fluid cell culture to determine the enzyme activity. If a clear diagnosis is made prenatally, the pregnancy can be terminated in time to prevent the birth of a baby with mucopolysaccharidosis.