Mental retardation is the most frequently occurring handicap in children. It interferes
with learning, social and psychological development.This work was planned, to
throw light on mental retardation in Libya, by studying the possible biochemical
factors affecting the etiology of this medical and social problem. One hundred and
thirty three mentally retarded Libyan children from both sexes were engaged in this
study. They were grouped according to etiology of mental retardation into: Down's
syndrome (Group I), cerebral palsy (Group II)and other causes rater than DS or CP
(group III). Serum levels of amino acids were assayed for all studied groups.
The results obtained revealed that, the level of serum amino acids, serine,
glutamine, histidine and arginine were significantly lower in group I than controls. In
group II, the level of serum asparagine was statistically higher while the level of
glutamine was statistically lower than control. Also, in group II, the levels of
asparagine, serine, proline and histidine were statistically higher than group I. In
group III, the levels of serine, histidine and arginine were statistically significantly
higher than in group I. In group III, significant increase was detected as regards
tyrosine, leucine and phenylalanine, while, only glutamine was lower than controls.
Low level of serine was noticed to be specific in Down's syndrome in Libyan patients
and in other patients as well. So the level of serum serine may be controlled by
special diet or special treatment (drugs) to improve their I.Q levels.
In conclusion,to confirm the biochemical results obtained from the present study
in Benghazi and on a national level, a largerscale study should be performed on a
larger sample size with more facilities to diagnose all types of abnormalities. Also, to
evaluate the influence of other risk factors as dietary, cultural and environmental
factors on the prevalence and different degrees of mental retardation among infants
and children.