Content
Phenylketonuria is a rare genetic disease characterized by the presence of a mutation responsible for altering the function of an enzyme in the body responsible for the conversion of the amino acid phenylalanine into tyrosine, which leads to the accumulation of phenylalanine in the blood and which in high concentrations is toxic to the organism, which can cause intellectual disability and seizures, for example.
This genetic disease has an autosomal recessive character, that is, for the child to be born with this mutation, both parents must be at least carriers of the mutation. The diagnosis of phenylketonuria can be made right after birth by means of the heel prick test, so it is possible to establish treatment early.
Phenylketonuria has no cure, however its treatment is done through food, and it is necessary to avoid the consumption of foods rich in phenylalanine, such as cheese and meat, for example.
Main symptoms
Newborns with phenylketonuria initially have no symptoms, but the symptoms appear a few months later, the main ones being:
- Skin wounds similar to eczema;
- Unpleasant odor, characteristic of the accumulation of phenylalanine in the blood;
- Nausea and vomiting;
- Aggressive behavior;
- Hyperactivity;
- Mental retardation, usually severe and irreversible;
- Convulsions;
- Behavioral and social problems.
Usually these symptoms are controlled through an adequate diet and low in phenylalanine source foods. In addition, it is important that the person with phenylketonuria is monitored regularly by the pediatrician and nutritionist since breastfeeding so that there are no very serious complications and the child's development is not compromised.
How the treatment is done
The main objective of the treatment of phenylketonuria is to decrease the amount of phenylalanine in the blood and, therefore, it is usually indicated to follow a diet low in foods containing phenylalanine, such as foods of animal origin, for example.
It is important that these changes in food are guided by the nutritionist, because it may be necessary to supplement some vitamins or minerals that cannot be obtained in normal food. See how the food should be in case of phenylketonuria.
The woman with phenylketonuria and who wants to become pregnant should have guidance from the obstetrician and nutritionist regarding the risks of increasing the concentration of phenylalanine in the blood. Therefore, it is important that it is evaluated by the doctor periodically, in addition to following an appropriate diet for the disease and, probably, supplementing some nutrients so that both the mother and the child are healthy.
It is also recommended that the baby with phenylketonuria be monitored throughout his life and regularly to avoid complications, such as impairment of the nervous system, for example. Learn how to care for your baby with phenylketonuria.
Is phenylketonuria curable?
Phenylketonuria has no cure and, therefore, treatment is done only with the control of food. The damage and intellectual impairment that can happen with the consumption of foods rich in phenylalanine is irreversible in people who do not have the enzyme or have the enzyme unstable or inefficient with regard to the conversion of phenylalanine to tyrosine. Such damage, however, can be easily avoided by eating.
How the diagnosis is made
The diagnosis of phenylketonuria is made shortly after birth by means of the heel prick test, which must be performed between the first 48 and 72 hours of the baby's life. This test is able to diagnose not only phenylketonuria in the baby, but also sickle cell anemia and cystic fibrosis, for example. Find out which diseases are identified by the heel prick test.
Children who have not been diagnosed through the heel prick test can be diagnosed by laboratory tests whose objective is to assess the amount of phenylalanine in the blood and, in the case of very high concentration, a genetic test can be performed to identify the disease-related mutation.
From the moment that the mutation and the concentration of phenylalanine in the blood is identified, it is possible for the doctor to check the stage of the disease and the probability of complications. In addition, this information is important for the nutritionist to indicate the most appropriate diet plan for the person's condition.
It is important that the dosage of phenylalanine in the blood is done regularly. In the case of babies it is important that it is done every week until the baby turns 1 year old, while for children between 2 and 6 years old the exam must be carried out fortnightly and for children from 7 years old, monthly.