Phenylketonuria is a condition in which human body is unable to breakdown an amino acid called phenylalanine. Firstly, this condition is inherited and it results into increase in phenylalanine in the blood (Borison 363). Amino acids provide proteins into the body once broken down and phenylalanine being an amino acid is acquired in the diet. It can also be obtained from some artificial sweeteners. Without treatment, it can build up and cause serious health problems.
Phenylketonuria is caused by mutation in the gene that helps make an enzyme phenylalanine hydroxylase (PAH). When this gene, PAH, is defective the body cannot break down phenylalanine (Eisensmith 17). Classical PKU is an autosomal receding syndrome, caused by changes or mutations in both alleles of the gene for phenylalanine hydroxylase (also known as PAH), particularly found on chromosome 12(Clark 42). While in the body, PAH changes the amino acid phenylalanine to tyrosine, which is also an amino acid. The faulty protein allows dangerously high levels of phenylalanine to accumulate in the brain, poisoning the cells. If a person with PKU consumes too much phenylalanine, the build-up can cause mental retardation.
In families where autosomal recessive pattern is prevalent, then Phenylketonuria can be inherited. Autosomal recessive inheritance implies that a person has two forms of the gene that is changed. Usually, each parent of a person who has PKU has one form of the changed or mutated gene. The long-term outlook for people with PKU condition is excellent if they are compliant with therapy and if blood phenylalanine (phe) levels remain within the therapeutic range. Life expectancy should be normal, and most patients function independently in adult life.
At a health care centre or in a medical facility, the providers obtain a sample blood from a child’s heel in order to do a PKU test. The blood sample is the tested for levels of phenylalanine in it as well as other conditions the body may have.
A phenylketonuria test is done to check whether the right or required levels of enzymes needed for use by phenylalanine within the body. Phenylalanine is an amino acid that is needed for normal growth and development.
Apart from new-borns being tested for this condition, there are also pre-natal tests to for it. A couple may be tested for PKU carrier or condition to determine whether their new-born will have or has PKU or will be a carrier. This may be done through Chorionic villus sampling (CVS).
Phenylalanine isn’t a health concern for many individuals. However, for people who have the genetic disorder PKU or other related disorders, phenylalanine can be a serious health issue. Phenylalanine can lead to mental impedance/retardation, brain damage, seizures and other similar problems especially in people with PKU. To prevent or minimise the above condition, it is advisable one to avoid taking food rich in phenylalanine (Start 110). These foods include but not limited to: eggs, beef, cheese and nuts.
A lifetime diet with very limited intake of protein, because foods with protein contain phenylalanine. Some nutritional supplements may be used to balance the protein intake without phenylalanine. An example of such supplements is the PKU formula. This helps a person in having all the nutrients without affecting the general health of the individual.
Although Phenylketonuria is quite a rare disorder, both male and female gender are affected in the same measure. That is the main reason why new-borns should be screened for such and related disorders.
Borison, R. L., et al. “Metabolism of an amino acid with antidepressant properties.” Research Communications in Chemical Pathology and Pharmacology 21.2 (1978): 363-366.
Clark, Andrew G. “Mutation-selection balance with multiple alleles.” Mutation and Evolution. Springer Netherlands, 1998. 41-47.
Eisensmith, R. C., and S. L. C. Woo. “Gene therapy for phenylketonuria.” European Journal of Pediatrics 155.1 (1996): S16-S19.
Start, K. “Treating phenylketonuria by a phenylalanine-free diet.” Professional care of mother and child 8.4 (1997): 109-110.