Alkaptonuria, a genetic disease described in depth with data support

Essay by koolkid22High School, 10th gradeA, January 2004

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Alkaptonuria is an autosomal recessive trait that affects many parts of a victim's body. The genetic disorder has been mapped to chromosome 3, which is where the abnormality occurs. As an autosomal recessive trait, the parents of someone with alkaptonuria show no signs of the disease, but rather carry the gene and have a chance of passing it on the offspring. Two carrier parents have a 25% chance that the child will inherit two normal genes and, for a child with alkaptonuria, a 50% chance of the child being a carrier, and a 25% chance show no signs of the disease.

Alkaptonuria is a rare disease that is inherited. The disease results from a deficiency of the enzyme homogentisic acid oxidase. This enzyme deficiency leads to a build up of homogentisic acid in tissues of the body. Persons affected by alkaptonuria can note persistent, painless bluish darkening of the outer ears, nose, and whites of the eyes.

Symptoms of osteoarthritis can occur at ages that are premature for this form of arthritis, which typically affects persons after the age of 55 years.

Homogentisic acid accumulated in the urine will cause it to turn black. The urine from a person with alkaptonuria turns dark on standing if it is alkaline.

Calcification of cartilage can be detected on x-ray testing. In males, calcification of the prostate gland can occur. Heart valves can also become diseased due to alkaptonuria.

There is no effective treatment for the underlying enzyme deficiency of alkaptonuria. Ascorbic acid (vitamin C) has been found to prevent pigment deposits. Other diseases (symptoms) that go along with alkptonuria are ochronosis and osteoarthritis.

Ochronosis is the darkening of the tissues of the body that is caused by pigment composed of the excess homogentisic acid in patients with alkaptonuria. The pigment...