PKU Phenylketonuria

My Friend with PKU

DEF: Phenylketonuria is a rare metabolic disorder that affects the way the body breaks down protein. If not treated shortly after birth, PKU can be destructive to the nervous system, causing mental retardation

It is casued by a mutation in a gene on the number 12 chromosome. that gene codes for a protein, PAH (phenylalanine hydroxylase), an enzyme in the liver. when the mutation occurs the enzyme is unable to break down phenylalanine and a build up occurs. the build up can cause the blood to poison the nerve cells in the brain.

The gene is recessive so you would need to contract it from both parents to have this mutation. their would be a 25% chance of the child contracting it. Note: the parents or 'carriers' do not have the symptoms, it does not affect them. Both genes have to be infected with the mutation, not just one.

There are no noticeable symptoms at first. If not treated then the brain damage can cause epilepsy, behavioral problems, and stunt the growth of the baby.
Some other symptoms:
eczema (skin rash
a small head (microcephaly)
a musty body odor (from too much phenylalanine)
and fair skin (because phenylalanine is necessary for skin pigmentation).

The doctors find it by taking a small blood sample from the baby, after birth, and test it in the lab. the sample is normally taken from the heel or arm.

People with PKU must have a protein free diet. (most proteins contain phenylalanine.) Babies are given a formula but adults must stay away from foods with phenylalanine. (some will continue with the formula) Special foods are provided by support groups for people with PKU. *also artificial sweeteners need to be avoided.

about 1-15000 are born with it and it was discovered in 1934 by Norwegian doctor Asbjørn Følling