Alkaptonuria

Over the course of many years, homogentisic acidslowly builds up in tissues throughout the body.

Itcan build up in almost any area of the body, including the cartilage, tendons,bones, nails, ears and heart. It stains the tissues dark and causes a wide range of problems.

Joints and bones

When a person with alkaptonuria reaches their 20s or 30s, they may start to experience joint problems.

Typically, they'll have lower back pain and stiffness followed by knee, hip and shoulder pain. These are theearly symptoms of Osteoarthritis .

Eventually, cartilage(a tough, flexible tissue found throughout the body) may become brittle and break, leading to joint and spinal damage. Joint replacement operations are often needed.

Ears and eyes

An obvious sign of alkaptonuria in adults is thickening and blue-black discolouration of ear cartilage. This is known as ochronosis.

The earwax may also be black or reddish-brown.

Many people develop brown or grey spots on the whites of their eyes as well.

Skin and nails

Alkaptonuria can result in discoloured sweat, which can stain clothes and cause some people to have blue or black speckled areas of skin. Nails may also turn a bluish colour.

The skin colour changes are most obvious on areas exposed to the sun and where sweat glands are found the cheeks, forehead, armpits and genital area.

Breathing difficulties

If the bones and muscles around the lungs become stiff, it can prevent the chest expanding and lead to shortness of breath or difficulty breathing.

Heart, kidney and prostate problems

Deposits of homogentisic acid around heart valves can cause them to harden and turn brittle and black. Blood vessels can also become stiff and weaken.

This can lead to heart disease and may require heart valve replacements.

The deposits can also lead to kidney stones , bladder stones and prostate stones.