Autism: unable to handle the world's chemicals
April 28, 2005
Subject: Autistic children start out genetically more vulnerable to oxidative damage and susceptible to environmental and toxic attack than healthy children.
Autism is the biological hobgoblin of modern medicine. We are in the midst of an epidemic yet have few clues why it's happening. A new study takes us a step toward understanding the disease, and opens up the possibility of hope.
In the last 15 years we have seen a ten fold increase in the number of children diagnosed with autism. Part of this increase has been attributed to increased awareness and better recognition of the disease. Much of this jump is still real. There is a genetic component to the disease but genetics alone cannot account for the rapid increase we are experiencing.
Autism typically shows up in toddlers and is characterized by limited language skills, poor social interaction, repetitive behaviors, and limited interests. Autism often runs in families suggesting a genetic cause. A recent study by S. Jill James in the April, 2005 issue of Biology may help us make significant inroads toward understanding and treating this autism. James is the director of the department of biochemical genetics at Arkansas Children's Hospital. In a study of the blood of some apparently healthy children, the biochemistry of one sample stood out. It turned out the atypical sample came from a boy who was autistic. Curious, James got blood samples from 20 other autistic children. All the samples exhibited a similar unusual biochemical fingerprint, which James has now confirmed in 75 autistic children. In a control group of 75 healthy kids none showed this same chemical fingerprint in their blood.
The autistic kids had unusually low concentrations of the antioxidant glutathione in their cells. The ratio of active glutathione to its inactive breakdown products was also unusually low.
“This pattern is consistent with an inability to detoxify [poisons], especially heavy metals,” such as mercury or lead, James says. That's because glutathione normally binds to heavy metals and the body then targets the molecular complex for elimination.
This new information makes sense in light of the therapies we have found clinically useful in treating autism. Several of the useful autism treatments have focused on reducing toxic load in the patient's body, especially heavy metals but also a range of organic poisons. These new ideas also tie in with the work of Bernard Shaw whose focus on bowl dysbiosis in treating autism now makes more sense. Shaw as a researcher at the CDC in Atlanta , noticed that some autistic children had high levels of fungal metabolites in their blood secondary to fungal or yeast growth in their intestines. These kids improved with anti- fungal treatment. Some of the chemicals produced by yeast can be neurotoxic; autistic kids may simply be more sensitive to these chemicals than healthy kids and experience negative effects even at very low concentrations.
This new understanding may also help us understand the vaccine business which has been so confusing. Clinical experience tells us that autistic kids routinely have elevated levels of toxic metals, especially mercury. There is an ongoing debate whether inoculating kids with vaccines preserved with mercury compounds trigger autism. Although there is plenty of anecdotal stories of kids supporting this theory, kids becoming autistic shortly after vaccinations, researchers have never been able to see a clear statistical trend. The manufacturers insist vaccines are safe. Now that we can identify a genetic subgroup by their blood chemistry, we may be able to find a statistical correlation. Vaccines may not trigger autism in ‘normal' kids but could be the last straw of toxic load in kids deficient in glutathione.
If this information “holds” we will be able to identify susceptible kids by their blood chemistry. Those kids at risk for autism can be protected environmentally to reduce their toxic exposure. There are nutritional tricks to erase this blood fingerprint and raise glutathione levels in healthy people; the same tricks appear to work in these kids. Whether or not changing this blood chemistry in autistic kids will reverse the disease process is the big question. In the mean time practitioners should certainly try to increase glutathione in autistic kids to see what happens. It's one of those things that won't hurt and might help a whole lot.
If nothing else watching for this chemical fingerprint in children with a genetic predisposition to become autistic may lead to early intervention and disease prevention. This is exciting news; expect to see follow ups on this in the future.
American Journal of Clinical Nutrition 2004 80(December):1611-1617.
Metabolic biomarkers of increased oxidative stress and impaired methylation capacity in children with autism
S Jill James, Paul Cutler, Stepan Melnyk, Stefanie Jernigan, Laurette Janak, David W Gaylor and James A Neubrander
Background : Autism is a complex neurodevelopmental disorder that usually presents in early childhood and that is thought to be influenced by genetic and environmental factors. Although abnormal metabolism of methionine and homocysteine has been associated with other neurologic diseases, these pathways have not been evaluated in persons with autism.
Objective: The purpose of this study was to evaluate plasma concentrations of metabolites in the methionine transmethylation and transsulfuration pathways in children diagnosed with autism.
Design: Plasma concentrations of methionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), adenosine, homocysteine, cystathionine, cysteine, and oxidized and reduced glutathione were measured in 20 children with autism and in 33 control children. On the basis of the abnormal metabolic profile, a targeted nutritional intervention trial with folinic acid, betaine, and methylcobalamin was initiated in a subset of the autistic children.
Results: Relative to the control children, the children with autism had significantly lower baseline plasma concentrations of methionine, SAM, homocysteine, cystathionine, cysteine, and total glutathione and significantly higher concentrations of SAH, adenosine, and oxidized glutathione. This metabolic profile is consistent with impaired capacity for methylation (significantly lower ratio of SAM to SAH) and increased oxidative stress (significantly lower redox ratio of reduced glutathione to oxidized glutathione) in children with autism. The intervention trial was effective in normalizing the metabolic imbalance in the autistic children .
Conclusions: An increased vulnerability to oxidative stress and a decreased capacity for methylation may contribute to the development and clinical manifestation of autism.
Experimental Biology 2005. April 2. San Diego . Abstract
Low plasma methionine, cysteine, and glutathione levels are associated with increased frequency of common polymorphisms affecting methylation and glutathione pathways in children with autism
S. Jill James, Stepan Melnyk, Stefanie Jernigan. Pediatrics, University of Arkansas for Medical Sciences, 1120 Marshall St. , Slot 512.40B, Little Rock , AR , 72202
Autism is a complex neurodevelopmental disorder that is thought to involve both genetic and environmental factors. The 10-fold increase in the prevalence of autism in the last 15 years is a major public health concern. Although abnormal thiol metabolism has been associated with other neurologic diseases, these pathways and related polymorphisms have not been evaluated in autistic children. Plasma levels of metabolites in methionine transmethylation and transsulfuration pathways were measured in 90 autistic and 45 control children using HPLC with electrochemical detection. Polymorphic variants in transcobalamin II (TCII), methylene- tetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR), catecholamine-O-methyltransferase (COMT), and glutathione-S-transferase (GST) M1/T1 were evaluated in 233 autistic children and 183
controls. The results indicated that mean levels of methionine, cysteine, total glutathione, and the ratio of oxidized to reduced glutathione were significantly decreased among the autistic children. The frequency of MTHFR 677CT/1298AG heterozygosity, TCII 776GG, COMT 1947GG, and the GST M1/T1 double null genotype was increased in the autistic children relative to controls. We hypothesize that an increased vulnerability to
oxidative stress (environmental and/or intracellular) may contribute to the development and clinical manifestations of autism.
Supported by the Autism Research Institute, San Diego , CA