Alkaptonuria Research Papers

Alkaptonuria

Ashley Thompson

Grand Canyon University

Alkaptonuria

Alkaptonuria (AKU), which is commonly known as the black urine disease, is a very rare autosomal recessive disorder that occurs due to the mutation in the Homogentisate 1,2 Dioxygenase Gene (HGD). The HGD gene is what provides interactions for the making of the enzyme called homogentisic acid oxidase (HGAO). HGAO is the enzyme that helps by breaking down the amino acids tyrosine and phenylalanine. Tyrosine is known as a non-essential amino acid with a polar side group and it has a special role to the phenol functionality. Tyrosine appears in the proteins that are a part of signal transduction processes. Whereas phenylalanine is more of an essential amino

Homogentisic acid is produced in the body from the improper breakdown of tyrosine and phenylalanine in the body. The excess homogentisic acid accumulates in the blood and also in the connective tissues such as cartilage and this happens in a great amount around the joints. The accumulation of blood leads to development of ochronosis, arthritis, heart issues discoloration of the skin in certain areas and many more complications that are seen in patients with AKU. In basis terms AKU is a disorder that results from the improper breakdown of tyrosine and phenylalanine because there is a deficiency of the enzyme HGAO. The gene that encodes the HGD enzyme was cloned in 1996 that is when they opened the era of molecular genetics of AKU. We now know that HGD gene consists of 14 eons (which are the coding parts of the gene) and 13 introns (which are the non-coding parts of the gene). The HGD gene has a tissue specific expression, particularly in the liver, kidneys, small and large intestines, prostate and the brain. Increased activity in the liver and kidneys has been attributed to metabolic activity of these organs in the

When this happens the urine will turn a dark blue-black color when it is exposed to air. Therefore it may not look abnormal as soon as it exits the body but actually turns colors if it sets for a period of time so that it is exposed to air to express the blue black color. Researchers define a high urinary level of homogentisic acid as being greater than four to eight grams in a twenty four hour period. With children dark staining in the diapers is a sign that homogentisic acid is present and being excreted and this can indicate that the child may have the AKU disorder. It is important to note that many patients do not show many signs and do not become aware of their disorder until they are in their third or fourth decade of life. There have been research studies that show that males have a tendency to have an earlier onset or the arthritic symptoms than females do, the difference in timing is unclear but may be due to the fact that males have a tendency to do more laboring work throughout their lifespan than women do in most