accumulation of excess phenylalanine causes _________________.
Phenylketonuria (PKU) can be defined as a rare metabolic disorder caused by a deficiency in the production of the hepatic (liver) enzyme phenylalanine hydroxylase (PAH). Astaxanthin is a carotenoid, a chemical found naturally in certain plants and animals. A type of algae makes astaxanthin. This algae is used as a source for the astaxanthin in supplements. Some types of seafood also contain astaxanthin. There is less evidence to support its use for other conditions. Optimal doses of phenylalanine have not been set for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it difficult to set a standard dose. However, commonly used dosages, depending on the condition, range from 150 mg to 5,000 mg daily. Causes and symptoms. PKU symptoms are caused by alterations or mutations in the genetic code for the PAH enzyme. Mutations in the PAH gene prevent the liver from producing adequate levels of the PAH enzyme needed to break down phenylalanine. A genetic disorder in which the body lacks the enzyme necessary to metabolize phenylalanine to tyrosine. Left untreated, the disorder can cause brain damage and progressive mental retardation as a result of the accumulation of phenylalanine and its breakdown products. Classical PKU is caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH). Over 70 different mutations on the PAH gene found on Chromosome 12 have been found to cause the almost complete absence of PAH as seen in PKU patients. PKU patients deficient in PAH are unable to metabolise the amino acid phenylalanine leading to an accumulation of phenylalanine and it's metabolites within the body. PKU is an example of an autosomal recessive disorder. (ˌfɛn lˌki toʊˈnʊər i ə, -ˈnyʊər-, ˌfin-) n. an inherited defect of the ability to metabolize phenylalanine, requiring a diet free of or low in phenylalanine to avoid eczema, mental retardation, and other effects. PKU is a disease caused by the liver's inability to produce a particular type of PAH enzyme. This enzyme converts (metabolizes) the amino acid called phenylalanine into another amino acid, tyrosine. This is the only role of PAH in the body. A lack of PAH results in the buildup of abnormally high phenylalanine concentrations (or levels) in the blood and brain. Phenylalanine is not a widely accepted treatment for any condition. Some research, mainly from the 1970s and 1980s, offers some support for using it for depression. Several studies also showed that L-phenylalanine plus ultraviolet A light may be helpful for people with vitiligo. Tell a friend about us, add a link to this page, or visit the webmaster's page for free fun content. Link to this page: <a href=http://www.thefreedictionary.com/Deficiency+disease%2c+Phenylalanine+Hydroxylase>phenylketonuria</a>.
PKU