Phenylketonuria, otherwise known as PKU, is a rare genetic disease that is caused by a persons body being unable to metabolize the amino acid phenylalanine. The disease can cause mental retardation because the build up of phenylalanine in the body. When phenylalanine is not broken down and turned in a different amino acid, tyrosine, it can create other enzyme routes that build up in the blood stream and body tissue. This can be extremely harmful to the body and its development. This disease is caused by missing the enzyme phenylalanine hydroxylase, this enzyme is the one that normally breaks down phenylalanine. It is rare for this enzyme to be completely absence, but this form leads to the most severe mental retardation and neurological problems. Most cases occur when this enzyme is deficient and the amount of phenylalanine is slightly higher than usual amount in the circulatory system of a person. This is called hyperphenylalaninemia.. These disorders are different than normal PKU.(Shuett; McKusick)PKU occurs immediately when a child is born. The child appears to be completely normal, but can have blue eyes and can have fairer skin and hair than the rest of its family members. If PKU is unidentified early in an infants life they can have early symptoms which can be identified. Half of untreated babies while develop symptoms such as vomiting, irritability, an eczema-like rash, and a mousy odor to their urine (Bellenir 69). They can also have nervous system problems. Increased muscle tone, and very active tendon reflexes occur from these problems. Soon after they start to undergo mental problems. These problems are severe mental retardation and seizures among other things. Other indications are a smaller head than usual, prominent cheek and upper jaw bones with widely spaced teeth, poor development of tooth enamel, and decreased body growth(Bellenir 69).PKU is passed on in a autosomal recessive gene. This means that a ...
