Alkaptonuria is a rare genetic disorder which causes an accumulation of the intermediate metabolism of amino acids – homogentisic acid in the body. It causes darkening of urine dark brown or even black when exposed to air. The excess amount of acid causes damage to bone and cartilage, which are discolored and become brittle.

AlkaptonuriaAlkaptonuria treatment focuses on prevention and mitigation of possible complications, such as inflammation, osteoarthritis, or coronary heart disease.

Since alkaptonuria is a rare inherited disorder, it occurs when the body is unable to produce enough of the enzyme HGD, which has the task of breaking down toxic homogentisic acid, which accumulates in the cells.

This situation most often leads to an osteoarthritis – especially of the spine and large joints.

The symptoms of alkaptonuria

The first signs include dark spots on the baby’s diapers, which are the earliest symptoms of alkaptonuria. In childhood, there are also some other symptoms that with age become more visible. Urine becomes dark brown or black when exposed to air, may appear early onset of osteoarthritis as joint stiffness and pain in the lower back.

Other symptoms of the disease include:

  • dark spots on the sclera of the eyes;
  • thickened and darkened cartilage in the ears;
  • blue, slightly mottled skin discoloration, especially around of sweat glands;
  • dark sweat stains;
  • red earwax;
  • kidney stones and prostate stones;
  • arthritis – especially around the hip and knee.pacjent_szpital

With alkaptonuria often involves with heart problems, because accumulating homogentisic acid causes hardening of the heart valves. This may interfere with the proper functioning of contributing to the disorder aorta and mitral valve. In severe cases, it becomes necessary to replace heart valves. Accumulated acid also results in hardening of the blood vessels, which raises the risk of high blood pressure.

Causes of alkaptonuria

Mutations in a gene cause the disease, but the condition is an autosomal recessive inheritance, which means that to transmit the disease to offspring both parents must have the troublesome gene. Alkaptonuria is therefore extremely rare; there is an average of 1 in every 250.000-1000000 cases. The disease is most common in areas of Slovakia, Germany, and the Dominican Republic.

Diagnosis and treatment of alkaptonuria

The first suspicion of alkaptonuria most often occurs after noticing dark urine in the child. The tests are carried out traces of excessive amounts of homogentisic acid in the urine, and DNA tests to verify the mutant gene HGD.

A necessary in a case of illness also becomes a family history of the disease, but not many people know that it might be carriers of the defective gene.

The same treatment is not entirely realistic. Are used here usually low-protein diets, doctors also recommend consuming large amounts of ascorbic acid – vitamin C, which slows down the accumulation of acid in the cartilage homogenising. Unfortunately, these methods are not entirely effective. Most often, applies only measures focusing on prevention and mitigation of possible complications like:

  • arthritis,
  • heart diseases,
  • kidney stones.

Physicians and surgeons prescribe anti-inflammatory drugs, analgesics and physical therapy, which helps to maintain the flexibility and strength of muscles and joints. It is necessary to avoid overloading the joints, such as hard physical work or contact sports.owoce_leki

There are cases where there is a need to joint replacement surgery of the arms, knees or hips. Surgical assistance becomes indispensable also in the event of problems with the aortic and mitral valves of the heart. There are also treatments for diseases of chronic kidney stones or prostate.

Research is ongoing to verify the use of nitryzynon as a potential medication for the treatment of alkaptonuria. People suffering from this unpleasant genetic disease are at increased risk of:

  • arthritis of the spine, hips, shoulders and knees;
  • problems with the Achilles’ tendon;
  • multiple aortic and mitral heart;
  • coronary arteriosclerosis;
  • kidney stones.

Many of them can be delayed and treated by regular checks.

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