Autism Spectrum Disorder-associated Biomarkers for Case Evaluation and Management by Clinical Geneticists

David A. Geier; Mark R. Geier

Disclosures

Expert Rev Mol Diagn. 2008;8(6):671-674. 

In This Article

Porphyrin Biomarkers

Porphyrins are derivatives of the heme synthesis pathway and afford a measure of xenobiotic exposures.[7] Recent studies, conducted in three separate continents, have examined urinary porphyrin profiles in ASDs.[7,8,9,10,11,12] In each of the studies, mercury-associated urinary porphyrin profiles were found to be significantly increased across the autism spectrum, from mild to severe ASD diagnoses.[7,8,9] Previous studies also demonstrated that chelation therapy in ASDs resulted in significant reductions in mercury-associated urinary porphyrin profiles.[7,8,9] Furthermore, using the Childhood Autism Rating Scale, a recognized test of ASD severity, researchers found a significant increasing correlation between mercury-associated urinary porphyrin profiles and Childhood Autism Rating Scale scores prior to blinded laboratory testing.[12] Providing further support for these correlations, other studies have shown that ASDs, relative to controls, had increased: brain mercury levels;[13] blood mercury levels;[14] mercury levels in baby teeth;[15] and mercury in the urine/fecal samples following chelation therapy;[16] as well as decreased excretion of mercury through first baby haircuts.[17]

Porphyrins can be examined in ASDs using Laboratory Corporation of America (LabCorp) random fractionated urinary porphyrin (Test#120980) and red blood cell fractionated porphyrin (Test#803445) testing. Additionally, 2,3-dimercapto-1-propanesulfonic acid and meso 2,3-dimercaptosuccinic acid, previously shown to significantly lower mercury body-burden (and hence lower urinary porphyrins) and help reduce mercury-associated neurodevelopmental toxicity,[18] may improve clinical outcomes of ASDs.[19] The Autism Research Institute reported survey data collected from over 22,300 parents of ASDs. The survey includes a list of 45 medications, 23 nondrug supplements or biomedical treatments, and nine special diets used to treat ASDs. The parents rated the treatment on a six-point scale. Parents, assessing their children's condition before and after treatment, rated chelation therapy (or the removal of heavy metals) as the highest or best of these 77 choices. Interestingly, 76% of parents said that their child 'got better' on this treatment.[20]

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