Anti-vitamin D rickets is a genetic defective disease of the renal tubules, and there are two types of hypophosphatemic and hypocalcemic rickets. Familial hypophosphatemic rickets is due to defective renal tubules and loss of phosphorus by the kidneys, resulting in disorders of calcium and phosphorus metabolism, causing rickets. The mode of inheritance is sex-linked dominant, and it does not respond to the usual physiological doses of vitamin D. Therefore, it is also called anti-vitamin D rickets and sex-linked hypophosphatemia. The main biochemical abnormality seen in the laboratory is hypophosphatemia, but the relationship between different sexes, ages and serum should be noted. Serum phosphorus values decreased by 0.48-0.97 mmol/L (1.5-3.0 mg/dl), mostly around 0.65 mmol/L (2 mg/dl), blood calcium values were normal or slightly decreased, serum alkaline phosphatase activity was increased, and urinary phosphorus excretion was increased despite the presence of hypophosphatemia, indicating impaired phosphorus reabsorption by the renal tubules. Amino aciduria, glucosuria, phosphate and potassium have never been found. It has been found that even with impaired renal tubular phosphorus reabsorption, serum phosphorus concentrations may be normal during the first months of life because the glomerular filtration rate is quite low. So the earliest laboratory abnormality may be an increase in serum alkaline phosphatase activity. Urine routine and renal function are normal, and the rate of phosphorus reabsorption by the renal tubules is reduced. x-ray bone films show mild to severe rickets changes, with both active and recovered lesions, which are most easily detected in the femur and tibia. There is backward bone age and knee valgus or inversion. The epiphysis is widened and fragmented, and the bone trabeculae are thick. Cup-shaped changes can be seen in the proximal and distal tibia, as well as the distal femoral, radial, and ulnar epiphyses. Suggested tests: 1. Six blood biochemical tests: alanine aminotransferase, creatinine, urea nitrogen, serum glucose, triglycerides, total cholesterol. Blood biochemical examination items include blood urea (nitrogen) (BUN), creatinine (Cr), blood PH, sodium, potassium, chloride, calcium, phosphorus, blood glucose, alkaline phosphatase, etc. Normal values: Alanine aminotransferase (ALT): 35IU/L0-45. Creatinine (CRE): 1.9mg/dL0.5-1.5. Urea nitrogen (BUN): 14.6mg/Dl6.0-23.0. Serum glucose (GLU): 223mg/dL60-110. Triglycerides (TG): 217mg/dL50-200. Total cholesterol (TCH): 179mg/dL150-220. Examination procedure: Blood is collected intravenously and immediately sent for testing. 2.Bone and joint radiographs of extremities Content: Bone and joint radiographs of extremities are taken of the extremities and related joints to confirm the bone condition after fracture. The width of the joint gap also varies according to age and location. During growth and development, the joint gap gradually becomes narrower as the epiphyseal cartilage gradually ossifies, and in the elderly, the joint gap becomes narrower as the cartilage degenerates and becomes thinner. The joint space becomes narrower in the elderly due to cartilage degeneration. When taking the film, observe whether there are any abnormal shadows. Preparation: No special preparation is needed for the skull, chest, and extremities. When the abdomen, lower spine, pelvis and urinary tract are photographed, the intestinal contents must be removed, otherwise the diagnosis will be affected. Photography steps: Carefully check the patient’s name, gender, age, and location of the film. Select the appropriate size film cassette according to the examination site. Placement number, date, left and right markers. Selection of filter grids. Generally, parts with a thickness of more than 12 cm need to be used. Removal of clothing or substances on the body that interfere with X-ray penetration, such as hairpieces, ornaments, ointments and dressings (depending on the actual situation). Select appropriate exposure conditions, focal point size, kilovolts, milliamps, time, and focal-slice distance. Photography parts related to breathing (e.g., chest, abdomen) should be trained to breathe out, breathe in, and hold the breath. Position yourself, measure the centerline, and start the machine exposure. Photography is completed to make a record of photographic conditions.