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Phenylketonuria

Phenylketonuria

“Almost all the chewing gum (Orbit, Stimorol …) there is the inscription” is contraindicated for patients with phenylketonuria. “What kind of disease is this and why there is a contraindication?”.
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To start a brief biochemical information. Phenylalanine is an essential amino acid for (substances that go to form proteins in the body) as the tissue of animals can not synthesize it. In the human body, where phenylalanine ingested with the food, the process of oxidation by a specific enzyme phenylalanine hydroxylase to fully amino acids – tyrosine. Violation (blocking) of the responses observed in violation of phenylalanine synthesis in the liver, causing severe hereditary disease – phenylketonuria.
Tyrosine is used by the body for the synthesis of thyroid hormones. A melanin, a derivative of tyrosine and phenylalanine, provides pigmentation (color color) of the skin, eyes and hair.
Also called phenylketonuria fenilalaninemiey, fenilpirovinogradnoy oligophrenia. Disease refers to inborn errors of metabolism (metabolism), characterized by increased levels of phenylalanine in the blood plasma and is accompanied by mental retardation. The exact cause of mental retardation in phenylketonuria is unknown, but it is a consequence of the biochemical defect. The hereditary nature of the disease is found in most people. The incidence of PKU in the U.S. is about 1 in 16,000 births.
Clinical symptoms of phenylketonuria in newborns are usually not available, so be sure to conduct laboratory screening (diagnosis). In rare cases, there is lethargy and difficulty in feeding. The majority of untreated patients, the disease manifests some degree of mental retardation (most severe), which is the main symptom of phenylketonuria. Usually patients are lighter skin, hair and eyes than their healthy relatives. Some children may experience skin changes resembling infantile eczema.
For patients with phenylketonuria abundant characteristic neurological symptoms, especially changes are reflexes. In older children, marked both large and small seizures, abnormalities in the EEG recorded in the 75 – 90% of cases. Developed a pronounced increase in activity and psychosis, often from patients an unpleasant “mouse” odor caused by the presence of phenylacetic acid in urine and sweat.
Diagnostics. After the newborn is getting milk (a source of phenylalanine) for at least 48 hours, doctors perform screening test for phenylketonuria (examine a drop of blood). At the age of 4 – 6 weeks, a breakdown product of phenylalanine can be detected in the urine of a sick child. At this time, spend another screening test for phenylketonuria. Urinary test performed after the newborn period, and children from families where there is a patient with phenylketonuria, it should be repeated regularly during the first year of life.
The treatment is to limit the inflow of phenylalanine from food to meet the need for this essential amino acid, but no more; ensure normal growth and development, preventing the accumulation of phenylalanine in the body and the end products of its metabolism. Requires continuous monitoring of the level of phenylalanine in the blood of children. In the United States to replace the widely used milk product lofenalak, complete in all respects, containing a small amount of phenylalanine. Allowed the use of low-protein natural foods, such as fruits, vegetables, some grains, etc. The need for phenylalanine met by limited consumption of natural protein and residual phenylalanine lofenalake. Currently, commercially available products, completely free of phenylalanine. Product phenyl stock contains all the ingredients except phenylalanine, no fat, so its energy value is lower than that of other products.
Medical treatment should be from the first days of life. Only early and consistent treatment to prevent central nervous system and severe mental retardation. If treatment is started after 2 – 3 years of life, it can be used only to limit a marked increase in activity and ease during seizures.