When it comes to mucopolysaccharidoses, many people may be unfamiliar with it. Today I will introduce you to mucopolysaccharidoses so that you can have an understanding of this disease. What is mucopolysaccharidosis? Mucopolysaccharidoses (MPS) are a group of lysosomal accumulation diseases in which acidic mucopolysaccharide molecules are not degraded due to enzymatic defects in the lysosomes of the body. Mucopolysaccharidoses are a relatively rare genetic metabolic disease with an incidence of about 1 in 30,000. Depending on the clinical manifestations and the type of enzyme defects, mucopolysaccharidoses can be divided into 6 types, such as I-VII, except for type II which is X-linked recessive, and the rest are autosomal recessive diseases. Mucopolysaccharide, also known as aminoglucan, is the main component of intercellular connective tissue and is widely distributed in cartilage, cornea, blood vessel wall and subcutaneous tissue, and also widely exists in various mammalian cells. HA), etc. The first three are closely related to this group of diseases. And what are lysosomes? Lysosomes (lysosomes) are an organelle in eukaryotic cells containing a variety of acidic hydrolases that specialize in the breakdown of various exogenous and endogenous macromolecules. The degradation of these polysaccharides must be carried out in the lysosomes, and 10 kinds of lysosomal glycosidases, sulfatases and acetyltransferases are known to be involved in their degradation process, and any one enzyme defect will cause the breakdown of amino-glucan chains to accumulate in the body, so the lysosomes are like garbage disposal stations, and the excess mucopolysaccharides are like garbage, which cannot be disposed of in time and are deposited in the body causing damage to the organism, and a large amount of Mucopolysaccharide is excreted from the urine. Mucopolysaccharide is deposited in fibroblasts and stained as balloon-like cells called Hurler cells, which are found in reticular cells of liver, spleen and lymphoid tissues, etc. Similar accumulation is found in chondrocytes, osteoblasts, central nervous system and peripheral ganglia, and retinal cells and corneal cells. It is deposited in the endocardium to form patchy thickening, and in the aorta, pulmonary arteries, coronary arteries, and arterial walls of the brain, kidney, liver, spleen, and extremities. The accumulation of mucopolysaccharides in various systemic organs leads to pathological changes and clinical symptoms in these organs. Most of the mucopolysaccharidoses of all types develop around the age of weeks, have a progressive course, and accumulate in multiple systems with similar clinical symptoms. In summary, they include ugly face, boat-shaped head, large head, thick eyebrows, prominent forehead and cheekbones, hairy and low hairline, low nasal bridge, large nostrils, small jaw, thick lips; skeletal deformities, short stature, adult height often below 120 cm, or between 120 cm and 140 cm, posterior or lateral spine, common knee valgus, claw-like hands; mental retardation; eye lesions; common hepatosplenomegaly, deafness , heart valve damage, atherosclerosis, etc. If there is a lack of understanding of mucopolysaccharidosis, it is often misdiagnosed as calcium deficiency, rickets, etc. As a result, a lot of calcium supplementation does not work, and the symptoms become more and more severe, and the treatment becomes less and less effective. The clinical manifestations of each type vary greatly, and even for the same type, there are individual differences in clinical manifestations. The severe cases often die prematurely at the age of about 10 years due to damage to important organ functions. In terms of mode of inheritance, all autosomal recessive disorders are inherited, except type II, which is X-linked recessive. Autosomal recessive disorders are those in which both parents carry one gene, but usually do not develop the disease, and both genes are given to a child who develops the disease. MPS type II is an X-linked recessive inheritance, i.e., the mother is the carrier of the disease causing gene, and the chance of having a girl without the disease is about 50% for a boy. When clinically encountering children with ugly faces, skeletal deformities, hepatosplenomegaly, and mental retardation, the possibility of mucopolysaccharidosis should be considered, and relevant auxiliary examinations are needed to confirm the diagnosis: 1. 2, urine mucopolysaccharide detection: including quantitative mucopolysaccharide detection methods and agarose gel electrophoresis analysis, is one of the important screening methods for mucopolysaccharidosis. 3, enzymatic analysis: using peripheral blood leukocytes or cultured fibroblasts, determine the intracellular lysosomal enzymes The activity of various intracellular lysosomal enzymes can be clearly diagnosed and typed for mucopolysaccharidosis. With the development of research equipment and technology, tandem mass spectrometry can now be used to detect the activity of various lysosomal enzymes in peripheral blood filter sheets to screen for a variety of lysosomal accumulation diseases including mucopolysaccharidoses.4. DNA analysis: With the development of molecular biology, especially the deciphering of the human genome, the causative genes of various types of mucopolysaccharidoses have been localized, and mucopolysaccharidoses can be genetically diagnosed. The Department of Endocrinology and Metabolism of Guangzhou Women’s and Children’s Medical Center has carried out screening methods for mucopolysaccharidoses such as urinary mucopolysaccharide quantification and electrophoretic analysis, and established enzymatic diagnosis methods for various lysosomal accumulation diseases including mucopolysaccharidoses, hoping that suspected patients will come to the clinic for early diagnosis and treatment. With the progress of science, mucopolysaccharidoses have become treatable diseases. Early diagnosis and early administration of hematopoietic stem cell transplantation or enzyme replacement therapy can cure or alleviate the disease process and significantly improve the prognosis of children with mucopolysaccharidoses. Currently, enzyme replacement therapy for mucopolysaccharidosis types I, II and VI has been performed abroad with satisfactory results. Enzyme replacement therapy is simple and low risk, but lifelong treatment is required, and medical cost is a serious problem. There is no drug supply in China at present, moreover, enzyme preparation cannot reach the central nervous system, and its role in improving neurological symptoms or preventing further damage to the nervous system is very limited, while hematopoietic stem cell transplantation is the only treatment method that can improve central nervous system symptoms and prevent further damage. With the successful implantation of allogeneic hematopoietic stem cells, leukocytes can provide normal or near-normal lysosomal enzymes, which can improve cognitive function, promote motor development, delay the disease process or cure the disease and improve the quality of life. It has been confirmed that mucopolysaccharidosis types I, VI, and VII have positive efficacy for hematopoietic stem cell transplantation treatment. Since types II, III, and IV are often associated with severe mental retardation or skeletal deformities, the efficacy of treatment may not be satisfactory when carried out after the appearance of clinical symptoms. However, with the improvement of hematopoietic stem cell transplantation technology and the improvement of screening and diagnostic methods for mucopolysaccharidoses, more children are diagnosed and treated early before the onset of symptoms, which greatly reduces the transplantation-related mortality and disease disability rates, and all types of mucopolysaccharidoses are now considered to have indications for hematopoietic stem cell transplantation. The efficacy of HSCT treatment is generally considered to be better before the age of 2 years. In China, research on hematopoietic stem cell transplantation or enzyme replacement therapy is also being actively conducted. Mucopolysaccharidoses is a chronic, progressive disease, and special treatment is expensive, bringing heavy mental and economic burdens to society and families. While strengthening the work of early diagnosis and early treatment of patients, genetic counseling and prenatal diagnosis should be actively carried out to prevent the birth of patients with mucopolysaccharidoses and improve the quality of the birth population. Prenatal diagnosis can be done by amniocentesis in the middle 17-20 weeks of pregnancy, and amniotic fluid cells cultured for enzymatic determination and genetic analysis, which is suitable for those who have patients in their families or have given birth to affected children.