Phenylketonuria (PKU) is a rare pathology that is predominantly hereditary in nature. With the disease there is a violation of the metabolism of amino acids, they accumulate in the cells of tissues and become toxic to the body. In the process of the disease, serious brain damage is possible. If the disease is diagnosed untimely, and the patient did not receive effective treatment, it can lead to mental problems, seizures, mental retardation, etc. Newborn children with this diagnosis may have a small-sized head, cardiovascular abnormalities, and underweight.
Symptoms
How phenylketonuria manifests in newborns
Newborns with phenylketonuria are initially asymptomatic and develop slowly over several months due to the gradual accumulation of phenylalanine in the body. The disease can only be detected through neonatal screening.
The longer a child with phenylketonuria does not receive specific treatment, the faster mental retardation and irreversible developmental disorders develop. In addition, children with phenylketonuria are characterized by the following signs:
- Specific bad breath, skin or urine odor, which can be compared to a musty “mouse” odor;
- Attacks of nausea and vomiting;
- Photosensitivity;
- Neurologic disorders, which can often include epilepsy (50%);
- Extrapyramidal disorders (parkinsonism is a neurological syndrome characterized by resting tremor, muscle rigidity and general slowness of movement);
- Visual disturbances: strabismus, optic atrophy, decreased visual acuity;
- Skin rashes like eczema, localized on any part of the body;
- Light skin and blue eyes (due to the inability of phenylalanine to convert to melanin);
- Microcephaly (reduced size of the skull and brain with normal size of other parts of the body);
- Hyperactivity: restlessness, uncontrollable outbursts of anger, inability to concentrate on tasks, spontaneous loss of concentration;
- Intellectual disability: from mild intellectual disability to idiocy and imbecility;
- Behavioral, emotional and social problems: difficulty learning in educational institutions, decreased motivation in performing work tasks, decreased social communication, irritability, mood swings, social isolation;
- Mental disorders: depression, generalized anxiety, schizophrenia, bipolar disorder.
Children born to mothers with phenylketonuria and uncontrolled phenylalanine blood levels have a much higher risk of mental retardation because they are exposed to very high and toxic levels of phenylalanine before birth. These children may have low birth weight, causing problems with weight gain and physical development in the future.
Diagnosis of phenylketonuria
Diagnosis of phenylketonuria is performed in the maternity hospital on the fifth day after birth. To do this, after feeding, a blood test is taken from the baby. Further in the laboratory, the biological material is examined to determine the level of phenylalanine. In some cases, the composition of urine is analyzed. If the level of the amino acid is too high, the newborn is prescribed appropriate therapy.
If the baby was not detected in this disease due to a delayed examination, over time parents begin to notice the first signs of the disease:
- apathy and lethargy;
- seizures;
- pallor of the skin;
- disproportion of the head to the body.
If these signs appear, they become the basis for diagnosis.
The pathology can also be established through genetic analysis. It is relevant if there is a relative with phenylketonuria in the family. It may also require additional consultation with a geneticist or endocrinology specialist.
Is there a treatment?
There is a treatment for phenylketonuria. However, there is no treatment that completely eliminates the disease. The development of serious signs, symptoms, side effects and complications of this disease can be prevented. Here are the critical points to know:
- It is diagnosed early and a phenylalanine-restricted diet is started as early as possible from the first days of life.
- Most patients diagnosed and started on diet therapy have normal intelligence in the first 10-20 days.
- Lifelong treatment is necessary to prevent neurologic and physical deterioration.
Gene therapy for patients with phenylketonuria is still in the clinical trial phase. Successful results have been obtained in animals. However, research on humans is very limited.
Diet for phenylketonuria
Here is a list of foods that should be excluded:
- Milk and dairy products (yogurt, yogurt soup, cheese, cheddar, etc.).
- Red meat and meat products (red meat, salami, sausages, fried meat)
- White meat and white meat products (chicken, turkey, fish, shellfish, mussels, etc.).
- Internal organs of animals, by-products (brain, liver, kidneys, spleen, etc.).
- Eggs
- Dried nuts (hazelnuts, peanuts, chickpeas, chickpea seeds, almonds, walnuts)
- Legumes (dried beans, lentils, fodder beans, soybeans, dried beans)
- Regular breads (wheat bread, rye bread, oat bread, corn bread) and products made from them (crackers, cookies, cakes, cookies, brownies and all foods made with these types of breads)
- Chewing gum, products containing aspartame and phenylalanine.
These are foods that should be excluded from the diet in phenylketonuria.
Foods that can be included in the diet are those that do not contain phenylalanine, and oils and net carbohydrates are important sources of energy for phenylketonuria patients.
What can be advised to phenylketonuria patients and their parents to improve their quality of life?
Phenylketonuria is a hereditary disease, so it cannot be prevented. However, with adherence to dietary therapy, a healthy lifestyle can be maintained, preventing neurological, physical and developmental disorders.
Because the treatment is lifelong, it can be overwhelming for the child and the parent.
To cope with this situation, the first thing to do is to accept the illness, then make the child’s school and teachers in the district aware of it, and direct the child according to his or her abilities to various recreational hobby activities (swimming, sports, music, art classes, camping, etc.).
Conclusion
Phenylketonuria is a serious hereditary metabolic disorder that can cause severe developmental, neurological, and physical issues if left untreated. Early diagnosis through neonatal screening is crucial for effective management, with dietary restrictions playing a key role in preventing complications. Although there is no cure for PKU, lifelong adherence to a phenylalanine-restricted diet can help patients lead healthy lives with normal intellectual development. Gene therapy is still in experimental stages, but advancements in treatment offer hope for the future. With proper care, support, and a tailored lifestyle, individuals with phenylketonuria can maintain a good quality of life and minimize the impact of the disease on their daily activities.
