Current State of Autism Research
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Transcript of Current State of Autism Research
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Current State of Autism Research
James B. Adams, Ph.D.Professor, Arizona State University
Science Director, Autism Research Institute/Defeat Autism Now!Parent of a 17-year-old girl with autism
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What is Autism?Autism is a label for people who have major
impairments in three areas:speech/communicationsocial interaction/friendshipsrestricted, repetitive, stereotypic behaviors
Autism is a spectrum disorder:Autism / PDD-NOS/ Aspergers
Impairment in social skills is common to all
Likely due to multiple causes.
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Research Tools for Diagnosing Autism
• Autism Diagnostic Interview – Revised (ADI-Revised): 2-4 hour interview with parents of child’s history
• Autism Diagnostic Observation Schedule (ADOS) – 1 hour structured interaction with child
Primarily used for research, not by clinicians
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Co-occurring symptoms• Mental Retardation – but must be tested with
non-verbal IQ test• Seizures: 25% (and 60% without seizures have
subclinical seizures)• Diarrhea/Constipation: 50%• Sleep problems: 50%• Low muscle tone: 30%• Pica: eating non-food items: 30%• Sensory Sensitivies: touch, vision, sound, taste,
smell, pain; under- and/or over-sensitive
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Early Onset vs. Regression
Data from Autism Research Institute (over 30,000 parental reports)
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Incidence
In US, latest report by CDC cites 1 in 150 for autism spectrum disorders (autism, PDD-NOS, Asperger’s).
In UK, a new unpublished study by Simon Baron-Cohen at Cambridge University found 1 in 100, and estimates the actual rate at 1 in 60.
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Genetic or Environmental Cause?
• Studies of identical twins reveal:– Co-occurrence is roughly 60% for autism, and
roughly 90% for speech delays; if 100%, then only due to genes; so genes are important, but so are unknown environmental factors.
• If a couple has one child with autism, then 5-10% chance other children will have autism, and 25% chance of major speech delay (so carefully monitor siblings)
Genetic vulnerability + environmental exposure
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Which Genes?
• Many genetics studies of autism, but they generally disagree, since too few subjects and too many genes
• Probably 10-20 genes involved in complex manner
• In 2 similar conditions, Fragile X and Rett’s Syndrome, a single gene has been identified for each
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Known Genetic Factors
There are several rare genetic disorders that greatly increase the risk of developing autism. These disorders include PKU, creatine formation/transport deficiency (uncommon), adenylosuccinate lyase deficiency, Angelman’s syndrome, Fragile X, Rett’s syndrome, neurofibromatosis, tuberous sclerosis, and others.
However, these disorders account for only roughly 5-10% of the cases of autism.
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Which Environmental Causes?
• No general agreement• Possible causes with limited scientific data include:
– Impaired methylation– Oxidative stress– Mercury/toxic metals poisoning (due to limited excretion
because of low glutathione)– Pesticide exposure (esp. organophosphates and
organochlorides)– Excessive oral antibiotic usage– Vaccine damage (especially MMR)– Lack of essential minerals (sulfate, iodine, lithium)– Other unknown factors
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Rapid increase in incidence• 1970’s: 2-3 per 10,000• 2008: 1 per 150 (autism spectrum); • Now affects about 1 in 94 boys, since 4:1 boy:girl ratio• In California (which has best statistics), autism now accounts for
45% of all new developmental disabilities
• Arizona: – 1996: 633 people with moderate/severe autism served by DDD– 1999: 1057– 2003: 1917– 2005: 2500– 2009: 3500
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Why rising rate of autism?
• Partly due to better awareness/diagnosis, but that is only modest effect (per study by MIND Institute)
• Not due to genetics alone – gene pool normally changes very slowly, although environmental toxicants can cause permanent genetic changes/damage
• So, primary reason is increased exposure to environmental factor (toxid metals, pesticides, antibiotics, MMR, iodine deficiency, other?).
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New Research on Risk of Autism
Preliminary research by Jill James et al on abnormalities in methylation cycle and glutathione in MOTHERS of children with autism
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SAM
SAH
Homocysteine B6
Oxidative Stress and transmethylation/transsulfuration
Cystathionine
Cysteine
GSH GSSG
Methionine
Adenosine
B6
B6
5-CH3THF
THF
5,10-CH2THF
Cell Methylation1
1
2
3
Folate Cycle
Transmethylation
Transsulfuration
2
3 Antioxidant Redox Potential (GSH/GSSG)
CBS
MTase
Methylation Potential (SAM/SAH)
MS
MTHFRB12 oxidized
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Intervention Trial with MethylB12 and Folinic AcidPlasma Metabolite Concentration
Autism Pre-treatment
(n = 40)
Autism Post-
treatment(n = 40)
p valuea
Methionine 21 ± 4b 22 ± 3 ns
SAM (nmol/L) 66 ± 13b 69 ± 12 ns
SAH (nmol/L) 15.2 ± 5 14.8 ± 4 ns
SAM/SAH (µmol/L) 4.7 ± 1.5b 5.0 ± 2.0 ns
Homocysteine (µmol/L) 4.8 ± 1.8 5.3 ± 1.1 0.04
Cysteine (µmol/L) 191 ± 24b 215 ± 19 0.001
Total Glutathione (µmol/L)
5.4 ± 1.3b 6.2 ± 1.2 0.001
Free Glutathione (µmol/L)
1.5 ± 0.4b 1.8 ± 0.4 0.008
GSSG (µmol/L) 0.28 ± 0.08b 0.22 ± 0.06 0.001
tGSH/GSSG 21 ± 6b 30 ± 9 0.001
fGSH/GSSG 6 ± 2b 9 ± 3 0.001
b Signficantly different from
age- matched control
children
a Treatment effect
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Research by Jill James et al. Autism Moms Control Moms (n = 46) (n= 200)
Methionine (µM/L) 24 ± 5 26 ± 6
SAM (nM/L) 80 ± 19 83 ± 13
SAH (nM/L) 33 ± 14* 23 ± 8.4 SAM/SAH Ratio 3.1 ± 1.7* 4.0 ± 1.4
Homocysteine (µM/L) 11 ± 3.9* 7.6 ± 1.6
*statistically significant
Maternal Methionine Cycle Metabolites:
It would be a very good idea to ask your physician to check your “total” homocysteine
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Maternal Transsulfuration Metabolites
Autism Moms ControlMoms Cysteine (µM/L) 232 ± 40 231 ± 20
Total GSH (µM/L) 5.1 ± 1.7* 7.3 ± 1.5
Free GSH (µM/L) 1.5 ± 0.5* 2.6 ± 0.6
GSSG (µM/L) 0.30 ± 0.08* 0.24±0.04
Total GSH/GSSG 17 ± 8 31
± 10* *statistically significant
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Metabolite imbalance and the risk of being a mother of a child with
autism
Stratified Group
ControlMothers
(N=200)
CaseMothers
(N=46)
Odds Ratio (Risk)
SAH >30µMol/L) 14% 54% 6.9
SAM/SAH <2.5 10% 54% 10.7
tGSH/GSSG <20 11% 65% 15.2
SAM/SAH <2.5 and tGSH/GSSG <20
3% 41% 46
In other words, 41% of ASD mothers had a 46x higher chance of having a child with autism, associated with abnormal methylation and oxidative stress
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It is not possible to determine from this data whether the abnormal metabolic profile in parents is genetically determined or whether it simply reflects the stress of living with an autistic child
Question: Would testing for abnormal methylation/glutathione in mothers and/or newborns, and treating it, reduce the risk of autism? Is this one possible method for preventing autism?
IMPORTANT CAVEAT
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Vulnerable to Toxins
• Decreased glutathione would make fetus more vulnerable to toxins, including toxic metals and pesticides
• Consistent with studies linking toxic metals (Windham et al 2006) and pesticide exposure (Roberts et al 2007) to risk of developing autism
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New research on possible cause of 12% of cases of autism by Judy van de Water and
colleagues at Mind Institute
A study of the mothers of children with autism (n=61) found that 12% of them had antibodies to fetal brain tissue. These antibodies were not found in any typical children (n=62).
Larger study of 300 children ongoing, and results are similar.
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Heavy Chain
Light Chain
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Summary of maternal Summary of maternal antibodies to fetal antibodies to fetal
brain proteins :brain proteins :
• Researchers found a specific subset of Researchers found a specific subset of antibodies to fetal brain proteins in the blood antibodies to fetal brain proteins in the blood of a subset of mothers whose children have of a subset of mothers whose children have autism.autism.
• These antibodies occur most frequently in These antibodies occur most frequently in those mothers who have children with those mothers who have children with regressive autism.regressive autism.
• Similar findings have been demonstrated in Similar findings have been demonstrated in work by Zimmerman and Singer against both work by Zimmerman and Singer against both rodent and human fetal brain. rodent and human fetal brain.
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The Autoimmune The Autoimmune PhenomenonPhenomenon
Question: Are the antibodies pathogenic?
Researchers currently have both primate and murine (mouse) models underway to determine the potential effect of exposure to IgG from the autistic maternal population during gestation on behavioral outcome.
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Primate model--Pilot studyPrimate model--Pilot study
• The gestating dams were exposed to 3 IV injections of IgG beginning late 1st trimester with 2 additional injections during the second trimester. – Group A exposed animals had 4 live births.– Group B exposed animals had 2 live births and will be
repeated.
• The offspring were monitored for several developmental criteria including motor coordination, mother preference test, and social interaction.
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Mother preference task
• Increased midline crossings
• Demonstrated no preference for own mother
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Social Dyad: Social Dyad: Measure of stereotypic Measure of stereotypic episodes with familiar pairingsepisodes with familiar pairings
• The weaned animals were placed in the observation cage with either a familiar monkey from their social group or an unfamiliar monkey.
• The AU treated offspring demonstrated severe stereotypies when placed in this environment.
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Summary
• It appears that 12% of mothers of children with autism have antibodies to fetal brain tissue.
• When injected into pregnant monkeys, those antibodies cause autistic-like behavior in their offspring.
• Currently working on commercialization of this test, so that mothers can know if they have this risk factor.
• Unknown what causes this abnormal antibody production in mothers.
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BiomarkersIn autism, there are many abnormalities in many organs and
systems, including the immune system, GI tract, brain, nutrition, metabolism, and detoxification.
The challenge is to determine which are primary, and which are secondary consequences, so that we know which to treat.
One way to do this is by focusing on biomarkers that correlate with the severity of autism.
However, it is unlikely that any one biomarker will cover all cases; rather, we expect several biomarkers for different causes and phenotypes of autism.
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Biomarkers (cont.)Biomarkers that correlate with the severity of autism include:
Urinary opioid peptides Total IgG (Heuer et al, 2008) R = -0.33, p<0.0001 (ABC)Porphyrins (Geier et al, 2008) R=0.28-0.31, p<0.05 (CARS)Serotonin (Adams et al, unpublished) R= - 0.37 (3 tests)Plasma Sulfate (Adams et al, unpublished) R=-0.42 (3 tests)Lysozyme (Adams et al, unpublished) R=0.47 (ATEC)Gut symptoms (Adams et al, unpublished) R=0.66 (ATEC)
In other words, many systems are affected in autism, and each contributes to the severity of autism, on average, with a lot of variation between children.
Note: R=0.33 means it explains about 10% of the variation in autism severity (R2 = %)
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GI Severity
• Overall GI symptom severity (GISS) correlates highly with autism severity (ATEC), R=0.66
• Lysozymes (a marker of GI inflammation) correlates strongly with autism severity (ATEC), R=0.47
• So, gut inflammation and GI symptoms have an important connection to autism
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Reduced Levels of Immunoglobulin in Reduced Levels of Immunoglobulin in Children with Autism Correlates with Children with Autism Correlates with
Behavioral SymptomsBehavioral Symptoms
•Heuer, Luke*1, 7,8, Ashwood, Paul*2, 7,8 , Schauer, Joseph 1, 7,8, Goines, Paula 1, 7,8,, , Hertz-Picciotto, Irva3,7,8, Hansen, Robin4,7,8, Croen, Lisa A5, Pessah, Isaac N6,7,8, Van de Water, Judy**1,7,8,
•As part of the Children’s Center for As part of the Children’s Center for Environmental HealthEnvironmental Health
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Reduced levels of IgG and IgM are indicative of an underlying defect in the immune system of children with autism.
Total IgG
Autism ASD Typical Delayed0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
N=105 N=24 N=96 N=32
* *
* *
Diagnosis
Total IgM
Autism ASD Typical Delayed0
1
2
3
4
N=116 N=27 N=92 N=29
*
Diagnosis
Total IgA
Autism ASD Typical Delayed0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
N=116 N=27 N=92 N=29Diagnosis
Total IgE
Autism ASD Typical Delayed0
500
1000
1500
2000
N=116 N=27 N=92 N=29Diagnosis
A. B.
C.D.
P=0.0001
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• This study provides a novel association This study provides a novel association between immune dysfunction and between immune dysfunction and behavioral parameters in autism.behavioral parameters in autism.
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Biomarkers (continued)
To determine which correlations are the most important, it is possible to use Regression Analysis (multiple correlations)
ex. Autism Severity = a (peptides) + b (porphyrins) + c (glutathione)
We have used regression analysis in two studies, and found that we can explain approximately half the severity of autism in each study.
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Regression Analysis – from DMSA study, Adams et al
Compare severity of autism with glutathione and metal testsadjusted R2 Most significant metals
• ATEC: 0.22 p=0.003 Pb-9, Sb-b• SAS: 0.36 p=0.002 Pb-b• PDD-BI: 0.25 p= 0.004 Sb-9, W-b, Sn-9
• ADOS: 0.49 p=0.0003 Hg-b, Al-b, Hg-9
All four scales of autism severity can be partially explained in terms of heavy metal excretion, with a very high statistical significance.
Suggests 22-49% of autism severity appears to be due to toxic metals, especially lead, antimony, and mercury.
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Regression Analysis – from Nutritional Assessment study, Adams et al
Compare severity of autism with nutritional biomarkers
adjusted R2 Most significant factors• ATEC: 0.34 p=0.0003 Serotonin, ATP, NADH
free carnitine
• SAS: 0.27 p=0.001 Serotonin, free sulfate
• PDD-BI: 0.20 p<0.002 Serotonin, free sulfate
All three scales of autism severity can be partially explained in terms of these factors, with a very high statistical significance.
Suggests part of autism severity related to abnormalities in serotonin, free sulfate, and mitochondrial factors (ATP, NADH, carnitine)
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Prognosis?Two major lifetime studies for adults – note that most of
these adults had little or no behavioral or medical intervention:
Autism: 90% of adults unable to work, unable to live independently, < 1 social interaction/month
Asperger’s (50% with college degrees):similar prognosis – social skills limit use of intellectual abilities
Grim prognosis if untreated, but many treatments now available, and there is MUCH more hope
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Autism is TREATABLE!
Behavioral Therapies
Biomedical Therapies
Many children now greatly improve, and some even recover, due to behavioral and/or biomedical interventions
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Autism Therapies
• Applied Behavior Analysis– most widely accepted/used
• Relationship Development Intervention (RDI) – new
• Other therapies
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Biomedical Treatments for Autism (based on the Defeat Autism Now! Guidelines)
• Improve Diet• Food Allergies• GFCF Diet (no wheat, no dairy)• Vitamin/Mineral Supplements• High-Dose Vitamin B6 and Magnesium• Essential Fatty Acids• Amino Acids• Gut Treatments• Thyroid Supplements• Sulfation• Glutathione • Detoxification• Anti-Viral Treatments• Immune System Regulation
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Future Research Needs
BiomarkersFocus on biomarkers, especially those that correlate with
severity of autism (need to integrate medical studies with behavioral assessments)
Focus on treatments that relate to biomarkers that correlate with severity of autism. We have many treatment options, but need to rigorously assess the efficacy of each.
Determine risk factors for autism, so that we learn how to prevent it.
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Future Research (cont.)
Pre-Screening:It is unlikely that a treatment will help all or even most children. So, it is important to use bio-markers to determine who is most likely to benefit.
Example: a treatment study with essential fatty acids (EFA) – only enroll children with low levels (we found that those who consumed little or no seafood were much more likely to improve than those who consumed 3+ seafood servings/month
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Future Research Needs (cont.)Multi-Treatments:
Almost all studies look at the effect of only 1 treatment, which usually helps only a subset of children, to a limited extent.
Since our goal is 100% recovery of the child, we need to investigate treating all of their known problems, instead of only one of them.
Example: We are planning a multi-treatment study that will test most of the DAN! guidelines, tailored to the individual based on testing. It will include a personalized special diet, vitamins/minerals, amino acids, essential fatty acids, gut treatments, methyl-B12/folinic acid, thyroid testing, etc. The goal is to assess the effect of the total, integrated set of treatments.
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Future Research Needs (continued)
FundingWe need to shift public and private funding from unsuccessful, over-funded areas (genetics, brain research) to new areas that directly relate to prevention and treatment
ARI appreciates the support of many donors, which have allowed it to fund many studies on the causes of autism and how to treat and prevent it.