الفهرس 
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Abstract
Phenylketonuria is an autosomal recessive metabolic disorder in which
the essential amino acid phenylalanine (Phe) cannot be converted into
tyrosine, leading to the accumulation of toxic metabolites. In the absence of
treatment, the clinical manifestations of PKU include mental retardation as
well as behavioural and dermatological problems. Consequently, PKU is
treated clinically by a diet aiming at a markedly reduced intake of Phe. The
dietary regimen of PKU is on synthetic or semisynthetic alimentary products
with no or low Phe content to cover protein requirements, and on certain
natural foods with a lower Phe content (especially fruit and vegetables) to
take care of the remaining needs (Dobbelaere et al, 2003)
Trace elements are essential in the daily diet because they have various
important functions. Protein and carbohydrate malnutrition can develop due
to deficiencies in micronutrients like vitamins and in trace elements like zinc
and copper which are involved in multiple biological processes as
constituents of enzyme systems including superoxide dismutase,
oxidoreductase, and glutathione peroxidase. Blood levels of zinc and copper
have been monitored in several experimental nutrition studies and are widely
used to determine the presence of the deficiency states or toxicity
(Cunninngham 2005).
Zinc is an essential mineral found in almost every cell and approximately
100 enzymes contain this element for biochemical reactions in the body and
its deficiency occurs due to inadequate intake, decreased absorption or
when there is increased loss of it from the body, or when the body’s
requirement for it increases (Anug et al, 2006).
Copper can affect different target organs such as bone marrow, the
central and peripheral nervous systems and the cardiovascular system
(Spinazzi et al ,2007).
The low ingestion of proteins with a high biologic value and the
predominance of vegetable-origin foods containing fibers, phytates,
oxalates, and tannins in the diet decrease the bioavailability of many
nutrients (Acosta et al, 1996).
Some studies reported low serum level of zinc and copper in
phenylketonuric children and adolescents ( Anderson et al, 2002 and
Barreto et al, 2008).
The study was conducted in the out-patient clinic of pediatrics in the
National Research Center on 31 children suffering from phenylketonuria (19
males and 12 female).Their ages ranged from 3 to 18 years with a mean age
of 11± 4.5. Full history taking, thorough clinical examination, assessment of
serum levels of zinc and copper, plasma phe assessment and IQ assessment
were done for all studied patients.
The overall consanguinity rate recorded in the current study was 90.3%
with a prevalence of family history of pku of 64.5%.
Different degrees of mental retardation were reported in 50% of pku
cases enrolled in the current study. The IQ of the studied sample ranged
between 30 and 90 with mean value of 68 ±16 .
The median of the values of phe was 12 ,with IQR (4-15).The mean
value of zinc concentration in the studied groups was 105.9 ±29.9 ,while the
mean value of copper was 88.8 ± 20.4 .
In the current study serum levels of zinc and copper were within normal
ranges in nearly most of the studied patients.
Non compliant children had significant higher phenylalanine and lower
IQ than compliant children.
There were significant negative correlation between IQ and ages at start
of diet therapy, ages of sitting, standing, walking, mother recognition and
speaking.
Significant negative correlation were found between phenylalanine and
weight, height and darkness of hair color, while there was significant
positive correlation with Cu.
IQ was significantly higher in children who received early diet therapy.