Alkaptonuria is a rare inherited disorder, a condition known as black urine disease where your body’s urine turns dark brown or black when it’s exposed to air and prevents the full breakdown of two amino acids tyrosine and phenylalanine that build up protein. In this condition, your body can’t produce an enzyme named homogentisic dioxygenase acid (HGD). The symptoms of alkaptonuria develop slowly due to chronic built-up of homogentisic acid within the connective tissue leading to a condition called osteoarthritis. Let’s explore the signs of this disease.
What are the Symptoms of Alkaptonuria?
Alkaptonuria disease symptoms develop slowly with chronic build-up of homogentisic acid within the connective tissue, mainly the cartilage and bones.People with alkaptonuria do not have symptoms immediately; symptoms usually show up when the individual is about 30 years old. These signs include:
When a person with alkaptonuria reaches their thirties, they may experience certain symptoms related to the joints and start to experience joint back pain, knee pain, and hip and shoulder pain and show early symptoms of osteoarthritis. In this condition, the cartilage, which is flexible tissue, may become hard and break, leading to joint damage. Doctors may suggest joint replacement surgery as treatment.
People with alkaptonuria develop brown or black spots on the inner whites of their eyes and may develop earwax due to the thickening of ear cartilage, making it book blue, grey or black. This is a condition known as ochronosis.
People with alkaptonuria may experience discolouration in their sweat on exposure to the sun and may develop blue and black-speckled areas of their skin, mostly on the forehead, armpits and genital areas. These people may also develop blue or black coloured nails.
- Heart, prostate and kidney stones
In the heart, deposition of homogentisic acid can cause chronic stiffness or pain around heart valves because of the narrowing and hardening of blood vessels. The weak and stiff blood vessels may result in heart disease and the patient may require heart valve replacements.
In the kidney and prostate, the deposition of homogentisic acid can also lead to kidney stones, bladder stones and prostate stones.