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Phenylketonuria or PKU is a rare metabolic disorder where a newborn baby is unable to break down an amino acid called phenylalanine into other products the body needs.
 * __ Phenylketonuria (PKU) __**

PKU is an autosomal recessive trait; therefore both parents must pass on the defective gene to develop the symptoms of the disorder. = = This mutation occurs in chromosome 12,the gene codes for a protein called PAH (phenylalanine hydroxylase), located in the liver. When this gene is mutated, the shape of the PAH enzyme changes and it is unable to properly break down phenylalanine. If not identified and treated after birth Phenylalanine builds up in the blood poisoning the nervous system in the brain causing mental retardation
 * Causes and Risk Factors **

**Symptoms**
Note that phenylalanine is also responsible for the production of the pigment for hair, eye, and skin color. So a child with lighter qualities than their siblings may be a sign of PKU.
 * Delayed mental and social skills
 * Head size significantly below normal
 * Hyperactivity
 * Jerking movements of limbs
 * Mental retardation
 * Seizures
 * Skin rashes
 * Tremors (shakiness)
 * Unusual positioning of hands

** Treatment **
PKU is a treatable disease, people with PKU must be on a protein-free diet, and since almost all protein enriched food contains phenylalanine. Foods that are not aloud are meat, eggs, cheese and nuts. A diagnosed infant is given a special formula called Lofenalac, which does not contain phenylalanine but has the source of protein and necessary amino acids. Also taking supplements like fish oil may help with brain development and motor coordination.



** Prevention **
PKU is easily detected with a simple blood test; because of this all states in the US require PKU testing to all newborns before removal from the hospital. It’s only a few drops of blood that can determine a child’s future. An enzyme assay can determine if parents carry the gene for PKU. Chorionic villus sampling can be done during pregnancy to screen the unborn baby for PKU. If identified a close watch over pregnancy is needed to make sure child does not inherit the mutation.

** Complications **
A child that doesn’t stay on as low as possible phenylalanine diet may experience ADHD (attention-deficit hyperactivity disorder). Severe mental retardation occurs if the disorder is untreated.

**Statistics**
About 1 out of every 15,000 babies in the United States is born with PKU. About 2% of the population are carriers of this gene   "PHENYLKETONURIA." //Learn Genetics //. University of Utah, n.d. Web. 10 Feb. 2013. .

"A.D.A.M. Medical Encyclopedia. Phenylketonuria." //PubMed health //. U.S. National Library of Medicine, 11 June 2011. Web. 10 Feb. 2013. "The Disease." //Prekulab //. N.p., n.d. Web. 10 Feb. 2013. .