Metabolic disease characterized by alteration of the degradation process of ' amino acid phenylalanine, resulting in accumulation of this compound in the body. It is also known as oligophrenia or phenylpyruvic idiocy. The disease is caused by a defect in ' enzyme phenylalanine hydroxylase that catalyzes a reaction pathway of acid degradation. The synthesis of this enzyme is encoded by a defective recessive gene on one of the non-sex chromosomes (autosomes). Thus, subjects heterozygous for this gene are carriers of phenylketonuria, while homozygotes show this disease.
The disease manifests itself towards the end of the first year of life, when you highlight the initial clinical manifestations related to mental retardation that causes the disease. At that time, in fact, is observed in children difficulty in the articulation of language and maintaining an upright position. The skin is typically affected by eczema . In subsequent years, there is an abnormal pattern of electroencephalographic trace ; crisis appear seizures and violent behavior.
There is no specific treatment for phenylketonuria, which can restore function already compromised by disease, is possibile però diagnosticarla precocemente, mediante esami prenatali (esame chimico del liquido amniotico) oppure, al momento della nascita, impiegando particolari reagenti che, al contatto con le urine del neonato, assumono una particolare colorazione. Le analisi del sangue rivelano un’elevata concentrazione ematica di fenilalanina. La diagnosi precoce della patologia permette di controllare l’insorgenza della malattia, attraverso la prescrizione di una dieta rigorosa, in cui siano assenti cibi contenenti l’amminoacido. Le confezioni di vendita di alcuni prodotti riportano l’indicazione “non contiene fonti di fenilalanina”, allo scopo di segnalare la loro innocuità against people with phenylketonuria.
"Phenylketonuria," Microsoft ® Encarta ® Online Encyclopedia 2008http: / / it.encarta.msn.com © 1997-2008 Microsoft Corporation. All rights reserved.
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