Ochronosis

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

• Ochronosis is an autosomal recessive disorder.
• Autosomal recessive will have an enzyme problem. With autosomal dominant inheritance, you will have a structural problem.
• This ochronosis will give you degeneration arthritis and low back pain.
• The homogentisic acid oxidase enzyme is defective and that extra homogentisic acid deposits in the joints leading to chondrocalcinosis.
• When the homogentisic acid deposits become polymerized, this leads to early arthritis.
• You can also have spondylitis with degenerative changes, disc space narrowing, and calcification.
• There can be a darkened, pigmented, full-thickness defect in the cartilage and a darkened synovium.