Porphyrinuria in childhood autistic disorder: Implications for environmental toxicity

Toxicology and Applied Pharmacology 214 (2006) 99 – 108, Received 13 February 2006; revised 23 March 2006; accepted 5 April 2006

Porphyrinuria in childhood autistic disorder: Implications for environmental toxicity

Robert Natafa, Corinne Skorupkab, Lorene Ametb, Alain Lama, Anthea Springbettc and Richard Lathed, aLaboratoire Philippe Auguste, Paris, France, Association ARIANE, Clichy, France, Department of Statistics, Roslin Institute, Roslin, UK, Pieta Research,

Abstract
To address a possible environmental contribution to autism, we carried out a retrospective study on urinary porphyrin levels, a biomarker of environmental toxicity, in 269 children with neurodevelopmental and related disorders referred to a Paris clinic (2002–2004), including 106 with autistic disorder. Urinary porphyrin levels determined by high-performance liquid chromatography were compared between diagnostic groups including internal and external control groups. Coproporphyrin levels were elevated in children with autistic disorder relative to control groups. Elevation was maintained on normalization for age or to a control heme pathway metabolite (uroporphyrin) in the same samples. The elevation was significant (P < 0.001). Porphyrin levels were unchanged in Asperger’s disorder, distinguishing it from autistic disorder. The atypical molecule precoproporphyrin, a specific indicator of heavy metal toxicity, was also elevated in autistic disorder (P < 0.001) but not significantly in Asperger’s. A subgroup with autistic disorder was treated with oral dimercaptosuccinic acid (DMSA) with a view to heavy metal removal. Following DMSA there was a significant (P = 0.002) drop in urinary porphyrin excretion. These data implicate environmental toxicity in childhood autistic disorder.

Excerpt: “Coproporphyrin levels were elevated in children with autistic disorder relative to control groups…the elevation was significant. These data implicate environmental toxicity in childhood autistic disorder.”