please excuse me if you are already aware of this but i find it intriguing so posting for any others who may be interested:
The plasma zinc/serum copper ratio as a biomarker in children with autism spectrum disorders (2009)http://informahealthcare.com/doi/abs/10 ... 0902783747
"The frequency of zinc deficiency, copper toxicity and low zinc/copper in children with autism spectrum disorders (ASDs) may indicate decrement in metallothionein system functioning. A retrospective review of plasma zinc, serum copper and zinc/copper was performed on data from 230 children with autistic disorder, pervasive developmental disorder-NOS and Asperger’s syndrome. The entire cohort’s mean zinc level was 77.2 μg dl−1, mean copper level was 131.5 μg dl−1, and mean Zn/Cu was 0.608, which was below the 0.7 cut-off of the lowest 2.5% of healthy children. The plasma zinc/serum copper ratio may be a biomarker of heavy metal, particularly mercury, toxicity in children with ASDs."
77.2 ug/dl of zinc is bad. converts to only 11.8 umol/L. that's borderline deficient even using the WHO's ridiculously huge 'normal' range. ms patients sit on average in the low teens. if you can get a serum zinc test for your son you could find out if he is in that low teens ballpark.
from researching levels seen in healthy controls, the zinc to copper ratio should be around 1.1 for optimal health, with the zinc and copper in the high teens but not too much over 20. eg zinc around 18 or 19, and copper around 17 or 18.