1, urine mucopolysaccharide quantification and electrophoresis: specimens are best used in morning urine, which can reveal an increase in the amount of mucopolysaccharide, and each type corresponds to a different type of mucopolysaccharide, such as dermatopoietin sulfate and heparan sulfate bands found in type I and II, heparan sulfate bands found in type III patients, and keratan sulfate bands found in type IV patients. The urine mucopolysaccharide electrophoresis in type III and IV patients is prone to false negatives. Zhang Huiwen, Department of Pediatric Endocrinology, Xinhua Hospital, Shanghai, China 2. X-ray film: orthopantomograph shows that the ribs look like “ribbon-like”; lateral spine film shows that the thoracolumbar vertebrae are dysplastic and have “bird’s beak-like” protrusions; orthopantomograph of the left hand shows that the proximal end of the metacarpal bone is pointed and the finger bones look like “bullet-head”. The left hand orthopantomogram showed that the proximal end of the metacarpal bone was pointed and the finger bones looked like “bullet head”. 3. CT or MRI of the head: the enlarged ventricles caused by high-pressure hydrocephalus can be found. 4. Peripheral blood lysosomal enzyme activity assay: The specimens that can be selected are peripheral blood leukocytes, skin fibroblasts and plasma. The enzyme activity is significantly reduced in patients with mucopolysaccharide storage disease type I. 5.Mutation detection of lysosomal enzyme-related genes: With the current technology, mutations should be detected in the vast majority of patients.