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  1. Reasons
  2. Symptoms
  3. Diagnosis
  4. Treatment


is a genetic disease that is associated with impaired utilization by the body an important amino acid called phenylalanine. The main signs of the disease is a specific of mouse smell from a child, too light skin and eyes (albinism), and disorders in physical and mental development, General weakness. Usually, the disease manifested in the first year of a child’s life because of misuse of phenylalanine are very fast. The disease is inherited.

Forms of phenylketonuria

Depending on the lack of an enzyme that is involved in the process of converting phenylalanine to tyrosine, there are the following forms (each of these enzymes takes part in the transfer of tyrosine to phenylalanine, but at different stages)

  • classic or severe (lack of phenylalanine-4-hydroxylase)
  • atypical forms (they are resistant to therapy because to treat them much more difficult, as the diet is the main cure of this disease)
  • the lack dihydropyrimidinase
  • the lack pyruvolytetrahydropterin.


Phenylketonuria in children is a genetic defect that is inherited.

Causes of phenylketonuria

  • marriages among close relatives, which increases the risk of developing the disease in a newborn baby
  • a gene variation (mutation) for a variety of reasons.


In such diseases as phenylketonuria, the symptoms already in the first weeks or months of baby’s life, but only if PKU is not detected in time. Signs of phenylketonuria

  • albinism is very light skin and blue eyes
  • a peculiar smell from baby’s skin, similar to a mouse
  • the rash of allergic nature of the skin small bumps (papules), small vesicles with transparent content (vesicles) and redness to the skin
  • weakness and lethargy
  • convulsions.
  • slow mental and physical development
  • disturbances in mental development, from the most mild forms of idiocy to develop at a later age.


Diagnosis of phenylketonuria is carried out in the maternity ward on the fifth day of the birth of the baby. To this end, after feeding take blood from baby’s heel and is examined the level of phenylalanine. It is also possible to research urine. If the level of amino acids high, the child is assigned a special treatment. These tests are taken from all children.

If your child has phenylketonuria, and the survey was not conducted in time, manifest characteristic symptoms such as lethargy, seizures, pale skin, and too small head size. In such a situation, the presence of these signs and results of blood tests attest to the presence of disease.

Also define phenylketonuria by using genetic analysis, which is most often carried out in the case of the family of a patient with phenylketonuria. You may want to consult an endocrinologist or medical genetics.


Diet restricting the intake of phenylalanine, which have to stick to it with phenylketonuria. This diet needs to adhere either to the onset of puberty the man or throughout life. Treatment of phenylketonuria includes

  • restriction of proteins of animal and vegetable origin and their replacement special nutritional protein mixtures
  • for children suffering from phenylketonuria, special formula, which contain much protein and not enough phenylalanine
  • the rejection of the carbonated sugary drinks, gum and candy containing phenylalanine
  • physiotherapy
  • drugs against seizures, if present.

Complications and consequences

If the patient has phenylketonuria, treatment initiated in a timely manner, the prognosis is quite favorable. With proper diet baby will normally grow and develop, and no damage will be. In this case, you can prevent dangerous consequences in the form of developmental disorders of the brain, destruction of individual cells, neurons, and other damage. In rare cases, nutritional therapy is not effective and does not help to avoid neurological disorders convulsions, the development of mental inferiority.

Prevention of phenylketonuria

The development of PKU is not preventable, since it is impossible to prevent the presence in the body of the child of the defective gene. If the disease develops, it is only important to prevent the emergence and development of serious brain injury by correct and timely assignment of diet. With the aim of prenatal diagnosis (before birth) can be shown to carry out genetic analysis in the medical-genetic consultation, which helps to predict the likely development of the disease in the child. Such actions are in families where there were cases of children born with phenylketonuria.