phenylketonuria II

August 12, 2017 17:51 | Genetic Diseases

This type of phenylketonuria is atypical.The first atypical phenylketonuria was described in 1974. The disease is transmitted in an autosomal recessive manner.The difference between this form of phenylketonuria discussed above is that a breach in the conversion of the amino acid phenylalanine amino acid tyrosine is localized at a different level in the chain of chemical reactions.As a result, the body builds up a large amount of phenylalanine and its derivatives, but in this case no longer acids and other compounds.With this type of phenylketonuria in the body there is a shortage of material tetrahydropterin taking part in the exchange of phenylalanine.

severe mental retardation, seizures, signs of increased excitability, increased reflexes, disturbance of muscle tone, spastic paresis of all extremities dominate the clinical picture of phenylketonuria II.progressive course of the disease and often leads to death in the 2-3 years of age.Patients are identified as a result of mass screening of newborns fo

r phenylketonuria.Phenylalanine level in the blood of these children naturally increased.Sooner begun dietary treatment can normalize the amount of phenylalanine in the blood, but does not prevent the appearance of symptoms that can be noted in the child at the beginning of the second half of life.

Diagnosis is based on determining the child symptoms, increase in the number of blood amino acids phenylalanine and massive urinary excretion its derivatives.Most of the diagnostic value of a load test with tetrahydropterin, which is given by mouth investigated.After 4-6 hours after receiving a single dose of a specific substance in a sharp reduction in blood phenylalanine levels up to full normalization parameter.It is noted at the same time increasing the content of the amino acid tyrosine, which is lowered by the level of phenylketonuria.

There is a possibility of prenatal diagnosis of phenylketonuria II.The object of research in this case are cells of the amniotic fluid.

Treatment of this type of phenylketonuria is also a diet with restriction of protein and foods containing phenylalanine.Requires reception of vitamin preparations, as well as the introduction of additional tetrahydropterin.The effectiveness of the treatment depends on the timing of its start.