The relation between the psychological functioning of children with Down syndrome and their urine peptide levels and levels of serum antibodies to food proteins.

AIMS To investigate the relation between psychological functioning of subjects with Down syndrome, and their levels of urine peptide and serum antibodies to food proteins. METHODS 55 children with Down syndrome in a cross-sectional study. Psychological functioning was measured by the Stanford-Binet Intelligence Scale: Fourth Edition, McCarthy Scales of Children's Abilities and Fagan's computer based test of novelty preference. RESULTS The participants, and their siblings, were found to have significantly increased total urine peptide levels. There were no significant correlations between peptide levels and psychological functioning. Significantly increased levels of IgG activity to gliadin and gluten, and IgA activity to gliadin, gluten and casein were found. There were significant negative correlations (Spearman r = -0.13 to -0.51) between psychological functioning, and IgG and IgA activity to gliadin and gluten. CONCLUSIONS A significant relation between antibodies to gluten and psychological functioning was documented. The mechanism and potential causal link are still unknown.