A blood test can help detect phenylketonuria.
Phenylketonuria is a metabolic disorder that causes the body to be unable to metabolize the amino acid phenylalanine in the liver . Also known as PKU , it is a hereditary disease caused by the lack of an enzyme called phenylalanine hydroxylase (abbreviated as FAOH) or tyrosine hydroxylase (DHPR) .
The origin of this term comes from the English phenylketonuria , hence the initials with which this disorder is referred to (PKU). This genetically transmitted disease is characterized by affecting certain chemical components of the body, the consequence of which can be intellectual disability .
People who are born lacking the enzyme phenylalanine hydroxylase (enzymes that activate certain chemical reactions in the body), which resides in the liver, cannot synthesize phenylalanine from food, and it begins to accumulate excessively in the body. It should be noted that people who do not suffer from this disease can synthesize this substance and convert it into L-DOPA , a neurotransmitter essential for the normal functioning of neurological development. There are seven essential amino acids for humans (leucine, tryptophan, valine, isoleucine, tyrosine, methionine and phenylalanine), which are obtained from the synthesis of certain components present in different foods.
Studies on phenylketonuria
Although it is a disease that is not widely known, it is known that in the United States alone, around 25,000 babies are born with PKU each year . In addition, although the exact origin of the disease is unknown, it is believed to be more common in individuals whose ancestors were Northern Europeans or Native Americans .
This genetic alteration , which is transmitted from father to son, was mainly promoted by Ivar Asbjørn Følling . This Norwegian medical expert was the one who described the disease in 1934 , before any other specialist.
Følling noted that the enzymes mentioned above are responsible for hydroxylating phenylalanine, in a reaction that allows the production of tyrosine. This means that if the body does not have any of these enzymes, it will suffer from an excess of phenylalanine in the blood (since this substance will not be able to be converted into tyrosine), and will result in other disorders .
People with phenylketonuria should not consume milk.
Symptoms and effects
The symptoms that children with this disease present are hair , eyes and skin that are lighter in color than the rest of their siblings (phenylalanine is one of the main responsible for the production of melanin , which allows the coloration of the skin and hair); delay in intellectual capacities ; a head that is smaller than expected; sudden movements and hyperactivity ; seizures and tremors ; and an unusual hand posture. It should be added that those people who do not receive treatment or avoid foods that contain phenylalanine, begin to eliminate a strange odor (comparable to that given off by mice or mold) through the skin, urine and breath ; said odor is due to the accumulation of this substance in the body.
The accumulation of phenylalanine and other substances (such as phenylpyruvate ) causes damage to the brain and central nervous system. People with phenylketonuria may therefore experience mental disability , seizures, spasms, tremors, and skin rashes.
Diagnosis and treatment of phenylketonuria
With tests and diagnostics that can detect this disease in newborns, it is possible to treat this condition by helping these individuals grow and develop in a healthy way. Treatment for phenylketonuria usually includes a diet that excludes foods with high amounts of phenylalanine, such as eggs or milk, as well as those containing aspartame .
To detect phenylketonuria, simple blood tests are performed (in some countries this test is among the mandatory tests performed on newborns). If the result is positive, new tests are performed to confirm the diagnosis and proceed with treatment.
It is important to know that this disease is perfectly treatable and that a series of precautions will be enough to ensure healthy growth for those children who suffer from phenylketonuria. Treatment includes a low-phenylalanine diet that requires exhaustive supervision by professionals, which if carried out correctly will ensure a much healthier adult life in physical and mental aspects than if it is carried out in a less compromised way.
There are alternatives specially developed for people who suffer from this disease that allow them to lead a healthy life without having to give up essential foods for growth, such as the aforementioned milk . Lofenalac infant milk powder, for example, is used as a source of protein for individuals with phenylketonuria. It is made with a low phenylalanine content and balanced in terms of the amount of the rest of the essential components for growth, such as amino acids.
Furthermore, it is vitally important that parents who have children with this disease have a clear awareness of the consequences that could affect them if the disease is not treated, or if the diet recommended by specialists is not followed properly, which may include chronic mental retardation that will appear in the first year of life and will then be irrevocable. Likewise, if parents do not know whether they may carry the gene for this disease in their genes, it is essential that when thinking about conceiving a new life, they carry out the respective enzymatic analyses, in order to be prepared in case their children may be carriers of this disease.
Finally, women who suffer from phenylketonuria must follow a strict diet , not only before becoming pregnant, but also during pregnancy and breastfeeding, even if the baby is born without the defective gene, because the accumulation of this substance in the mother's body could cause consequences in the child's body.