Re: What is the genetic disorder Pheynylketonuria?

Hi dear

Phenylketoneurea is a genetic disorder in which the body is not able to 
use one of the constituents of a normal diet, an amino acid - 
phenylalanine.  Phenylalanine is found in all protein foods such as meat 
etc and also to a lesser extent in cereals, vegetables and fruits. 
Proteins are composed of amino acids, and when we ingest proteins we break 
them down to amino acids which then is used to build our body proteins.   
Our body can convert some amino acids to others so that only some are 
essentially required (Phenylalanine is one of them). In Phenylketoneurea, 
phenylalanine is not be converted to Tyrosine (the enzyme bringing about 
the conversion is not present in the body of the PKU individual), and so 
Phenylalanine accumulates in the blood, this excess can retard physical 
and intellectual development. Tyrosine deficiency per se does not occur 
because the diet provides sufficient TYR. 

As you already know, PKU is a hereditary disease, its cause is the 
nonfunctionality of the enzyme which converts Phenylalanine to tyrosine.

Without treatment, Phenylalanine levels are markedly increased in the 
blood. As a result, brain development and function are seriously impaired. 
If untreated, PKU children may appear normal for their first few months of 
life, but will usually become mentally retarded before they are one year 
old.

I would like you to refer to some of the useful self-explanatory sites who 
deal at depth in PKU. http://ww2.mcgill.ca/pahdb/handout/handout.htm#The Heredity of PKU:
 http://www.peds.umn.edu/pku/
 http://www.pkuil.org/understand.htm