This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Ochronosis is the bluish-black or grey-blue discoloration of the skin, especially the ear cartilage, the ocular (eye) tissue, and other body locations. It can occurs in individuals with alkaptonuria, an inherited metabolic disorder; or because of exposure to various substances. Ochronosis typically occurs in adults, but has been reported in children. Ochronosis associated with alkaptonuria is caused by a mutation in the HGD gene, which results in the accumulation and deposition of homogentisic acid (HGA) in cartilage. The affected tissue becomes weak and brittle with time, leading to chronic inflammation, joint pain, and osteoarthritis. Alkaptonuria is inherited in an autosomal recessive manner. Alkaptonuria can be diagnosed based on the symptoms, laboratory testing, and genetic testing. There is no specific treatment for ochronosis associated with alkaptonuria and treatment is based on the symptoms.
When ochronosis is due to exposure to substances (called exogenous ochronosis), the condition is not inherited. Exogenous ochronosis is associated with malarial drugs, skin-lightening creams and over-exposure to the sun. Other than the skin findings, there are no other health affects. Exogenous ochronosis is difficult to diagnose. There is no specific treatment for this condition. Several different treatment options are available including prescription skin creams, vitamins, and laser treatments.
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