The main symptom of brownish-yellow disease arthritis is that the whole body skin, sclera and cornea pigmentation is brownish-yellow, the ear, nose and cartilage can become blue, the edge of the tympanic membrane is grayish-black, and the hearing is often reduced. Due to the lack of uronic acid oxidase, the intermediate metabolites of phenylalanine and tyrosine (uronic acid) cannot be further oxidized and decomposed, and accumulate in the body. This causes the skin, sclera and cartilage to become darker, while uronic acid 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. How to check for ear, nose and cartilage turning blue? After birth, patients with this disease have no symptoms other than placing urine oxidized to turn black-brown to make diapers stained black. It is not until after 20 to 30 years of age due to excessive deposition of black uric acid that a series of symptoms are produced. The main symptoms of patients with this disease are brownish-yellow pigmentation of the skin, sclera and cornea all over the body, the ears, nose and cartilage may turn blue, the tympanic membrane is grayish-black at the edges, and hearing is often diminished. If uric acid is deposited on the aortic and mitral valves, the valves become stiff and murmurs appear. In men, the disease is often combined with black prostate stones. Bone and joint changes usually erode the spine first, followed by the knee, shoulder and hip. The incidence of spondylitis is 10% to 15%, more in men than in women. The patient complains of lumbar pain and examination of the lumbar plate, loss of pronation, mild hunchback deformity, and posture similar to that of ankylosing spondylitis. Progressive stiffness of the spine, degeneration of the intervertebral disc, narrowing, calcification, marginal bone formation, and involvement of the intervertebral ligaments, even eventually causing bony ankylosis. Degenerative changes in the joint tissues of the extremities due to pigmentation, loss of elasticity of articular cartilage, thickening of synovial fibrosis, subchondral bone erosion and cystic changes with bone denseness, sclerosis and formation of bone redundancy can lead to joint ankylosis. The synovial membrane is villous and hyperpigmented, and there is pigmented cartilage debris in the joint fluid. X-rays show spinal changes with significant posterior protrusion of the thoracic spine and hyperflexion of the lumbar spine. The vertebrae are osteoporotic, with bone spur formation at the edges of the vertebrae in advanced stages. There is extensive degeneration of the intervertebral discs with laminar calcification and specific double transverse calcified shadows of flat, thin oval shape with increased density, parallel to each other and separated by a translucent layer. The intervertebral disc involvement is extensive, especially at the lumbar spine. The intervertebral space is significantly narrowed. The shoulder and knee joints may be degenerated, the tendon ligaments may be calcified, and the sacroiliac joint is narrowed with subarticular osteosclerosis. Calcification of the cartilage at the pubic symphysis is also present, with subchondral bone erosion. Calcification may also occur in the tendons and periarticular soft tissues attached to the femoral head, acetabulum, greater trochanter, lesser trochanter, and sciatic tuberosity.