Trace element concentrations in hair from autistic children.

The concentrations of 14 elements were determined in scalp hair samples from control, autistic and autistic-like children. Significant differences were noted between normal males and females for calcium, magnesium and mercury. The autistic population had significantly lower levels of calcium, magnesium, copper, manganese and chromium and higher levels of lithium as compared to sex- and age-matched controls. Children with autistic features (autistic-like), classified as having childhood-onset pervasive disorder, had lower levels of magnesium, cadmium, cobalt and manganese as compared to controls. Discriminant function analysis using the 14 trace elements correctly classified 90.5% of the normal and 100% of the autistic population. Using a stepwise procedure, the five elements with the greatest discriminatory power were calcium, copper, zinc, chromium and lithium. Analysis based on these five trace elements led to the correct classification of 85.7% of the normal and 91.7% of the autistic group. Results indicate that the concentrations of trace elements in hair from normal children differ from patterns observed in both autistic and autistic-like children. Furthermore, evidence suggests that hair analysis may have potential use as a diagnostic tool for autism.