The main symptom of brown yellows arthritis is that the skin, sclera and cornea of the whole body are pigmented with brownish yellow color, the ear, nose and cartilage can turn blue, the edge of the tympanic membrane is grayish black, and the hearing is often reduced. Brownish yellow disease is due to the lack of uronic acid oxidase, so that phenylalanine, tyrosine intermediate metabolites (uronic acid) can not be further oxidation decomposition, accumulation in the body. The skin, sclera, and cartilage become darker, while urea causes hyperpigmentation of cartilage and other connective tissues and degenerative arthritis of the spine and peripheral large joints. On the other hand, urinary black acid is excreted in urine, where it is alkalized and oxidized to make the urine darker, so it is also called black aciduria. This disease is a rare genetic disease and is rare. The prevalence is reported abroad as 3 to 5 cases per million population. Because uric black acid is easily deposited in cartilage, it degenerates joints. The disease is often seen clinically as arthrosis, so it is called brown yellowness arthropathy. What are the symptoms that are easily confused with it? 1, hematoporphyria formerly known as violet disease, is a rare disease, mostly due to genetic defects caused by the lack of enzymes related to the heme synthesis pathway resulting in disorders of porphyrin metabolism and disease. Clinical manifestations include photoreceptor skin damage, abdominal pain, neuropsychiatric symptoms, and increased blood pressure. According to the site of porphyrin metabolism disorder, it is divided into erythropoietic hematoporphyria and hepatic hematoporphyria. 2, urinary bilirubin Bilirubin is metabolically produced after the destruction of red blood cells. It can be divided into unconjugated bilirubin without liver processing and conjugated bilirubin formed by combining with glucuronic acid by the liver. Unconjugated bilirubin is insoluble in water and cannot pass through the glomerular membrane when bound to protein in the blood. Conjugated bilirubin has small molecular weight and high solubility, so it can pass through the glomerular membrane and be excreted in the urine. As the content of conjugated bilirubin in blood is very low in normal people, the amount of filtration is very small, so bilirubin cannot be detected in urine. If the increase of conjugated bilirubin in blood can pass through the glomerular membrane to increase the amount of conjugated bilirubin in urine, the amount of urine bilirubin test reacts positively. 3, hematuria Normal urine contains a very small amount of red blood cells. The sediment after centrifugation of middle urine can have 0 to 2 red blood cells per high magnification field under the microscope, if it exceeds this number, it is hematuria. 4, rheumatoid arthritis is a chronic systemic autoimmune autoimmune disease characterized by synovitis of the joints. Synovitis persistent recurrent attacks can lead to destruction of cartilage and bone in the joints, joint dysfunction, and even disability. The vasculitis lesions involve all organs of the body, so the disease is also known as rheumatoid disease. 5, ankylosing spondylitis Ankylosing spondylitis is a chronic progressive inflammatory disease that mainly affects the spine and can involve the sacroiliac and peripheral joints to varying degrees. The disease is also known as Marie-strümpell disease, VonBechterew disease, rheumatoid spondylitis, deforming spondylitis, rheumatoid central type, etc., now known as AS. AS is characterized by inflammation and ossification of the spinal joints and ligaments of the lumbar, cervical and thoracic segments and sacroiliac joints, the hip is often involved, and other peripheral joints can also be inflamed. The disease is generally rheumatoid factor-negative, so it is considered a seronegative spondylosis along with Reiter syndrome, psoriatic arthritis, and enteropathic arthritis.