Porphyrin changes in autism

Porphyrins and physiology

This is a group of normal compounds that are produced in the body, derived originally from 5-aminolevulinic acid, to make bile compounds and heme,   This is well described: see web site from Metametrix.  They show how the modification of body heavy metals would be expected to produce changes in the ratios of porphyrins being excreted in the urine. 

Urinary porphyrins

The reason why these are measured easily is because the method required is relatively simple, partly because many porphyrins are fluorescent or coloured.

Interpretation

It is difficult in these samples to assume that mercury poisoning is involved when generally mercury levels are not measured in the patients at the same time.   Detoxification of heavy metals followed by further porphyrin tests are not carried out and so currently research is difficult to interpret at this point.  One group did detoxify the autism group but did not find any change in heavy metal presence.  This does not explain the higher levels of the specific porphyrins.   Further research is required with much higher numbers of cases.

 

 

 

Porphyrins are made in this format, with 4 cyclic molecules in a ring. The different types, including heme are different from each other through chemical modifications of the outer sections and the carriage of metal ions in the middle of the ring

 

 

Porphyrin physiology

 

Urinary Porphyrin Profiling extract from Laboratory Evaluations in Functional and Integrative Medicine (Richard Lord and James Bralley Eds) see: www.metametrix.com/PDFs/Documents/Porphyrins_white_paper.pdf

 

 

Changes in the urine in autism

 

a)      Geier DA, Geier MR. A prospective study of mercury toxicity biomarkers in autistic spectrum disorders. J Toxicol Environ Health A. 2007 Oct;70(20):1723-30.   (significantly raised in autistic children in USA and in urinary samples in France: the different porphyrins found explained.)

b)      Geier DA, Geier MR. A prospective assessment of porphyrins in autistic disorders: a potential marker for heavy metal exposure. Neurotox Res. 2006 Aug;10(1):57-64.  (A significant increase (1.7-fold) in median coproporphyrin levels was observed among non-chelated ASD patients versus chelated ASD patients. Porphyrins should be routinely clinically measured in ASDs, and potential ASD treatments should consider monitoring porphyrin levels. Additional research should be conducted to evaluate the potential role for mercury exposure in some ASDs)

c)      Nataf R, Skorupka C, Amet L, Lam A, Springbett A, Lathe R. Porphyrinuria in childhood autistic disorder: implications for environmental toxicity. Toxicol Appl Pharmacol. 2006 Jul 15;214(2):99-108. (French group also finding high porphyrins and discusses the possible association with heavy metal exposure)

 

Involvement with heavy metal toxicity

 

Woods JS. Altered porphyrin metabolism as a biomarker of mercury exposure and toxicity. Can J Physiol Pharmacol. 1996 Feb;74(2):210-5. (Mercury selectively alters porphyrin metabolism in kidney proximal tubule cells, leading to an altered urinary porphyrin excretion pattern.  Changes in the urinary porphyrin profile are highly correlated with the dose and duration of mercury exposure and persist for up to 20 wk following cessation of mercury treatment. In the present studies, the utility of urinary porphyrin profile changes as a biomarker of mercury exposure in human subjects was evaluated. Urinary porphyrin concentrations were measured in dentists participating in the Health Screening Programs conducted during the 1991 and 1992 annual meetings of the American Dental Association and compared with urinary mercury levels measured in the same subjects. Among dentists with no detectable urinary mercury, mean concentrations of urinary porphyrins were within the established normal ranges for male human subjects. In contrast, among dentists with urinary mercury in excess of 20 micrograms/L, mean urinary concentrations of four- and five-carboxyl porphyrins as well as of precoproporphyrin were elevated three to four times those of unexposed subjects.  These findings suggest that urinary porphyrin profiles may serve as a useful biomarker of mercury exposure in clinical or epidemiologic studies of mercury-related human health risks.)

 

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