Mitochondrial Dysfunction and Autism Spectrum Disorders: A Simplified Approach by Daniel Rossignol, MD, & Richard Frye, MD, PhD

8/3/2019 Mitochondrial Dysfunction and Autism Spectrum Disorders: A Simplified Approach by Daniel Rossignol, MD, & Richar

1/8AUTISMSCIENCEDIGEST:THEJOURNALOFAUTISMONEISSUE02REPRINTEDWITHPERMISSION www.autsmone.org

daniEl a. RoSSignol, Md,FaaFP, received his doctorate omedicine at the Medical Collegeo Virginia and completed hisresidency in amily medicine at theUniversity o Virginia. He is currentlya physician at the InternationalChild Development ResourceCenter (ICDRC) in Melbourne,Florida. Coming rom an academic

background, Dr. Rossignolsearched the medical literaturelooking or a solution ater both ohis children were diagnosed withautism, and he has made it hismission to research and publish inautism. In the last 5 years, he haspublished 16 articles and 3 bookchapters concerning autism.

AUTISMSCIENCEDIGEST:THEJOURNALOFAUTISMONEISSUE02REPRINTEDWITHPERMISSION www.autsmone.org


2/8www.autsmone.org REPRINTEDWITHPERMISSIONAUTISMSCIENCEDIGEST:THEJOURNALOFAUTISMONEISSU

inTroducTionRecently, evidence has accumulated that some children with autismspectrum disorders (ASDs) have mitochondrial disease (alsoknown as mitochondrial disorders) or mitochondrial dysunction.Mitochondrial dysunction generally reers to mitochondria thatare impaired in unction but not severely impaired enough to ulfllthe criteria necessary or the diagnosis o mitochondrial disease.In essence, mitochondrial disease can be thought o as a severeorm o mitochondrial dysunction, and mitochondrial dysunctioncan be thought o as a less severe orm o mitochondrial disease. Imitochondrial dysunction can be represented by an engine that issputtering, mitochondrial disease would be represented by an enginethat is constantly in the repair shop.

The evidence or mitochondrial dysunction in ASD has expandedover the last several years based on multiple published papers on

this topic.1-5 This article reviews the role o mitochondria in health adisease, the proper unctioning o mitochondria, possible causes o

mitochondrial dysunction in ASD, laboratory testing and criteria thacan help identiy mitochondrial dysunction, and potential treatmenBeore beginning any workup or mitochondrial dysunction andbeore perorming laboratory testing or starting any treatment(including over-the-counter nutritional supplements), please consultwith your or your childs physician.

The role of miTochondriaIn the simplest terms, mitochondria are the powerhouses o the cell,generating energy rom the breakdown o ood. Figure 1 depicts amitochondrion and shows the pathways involved when mitochondrbreak down ood and use oxygen to create ATP (the energy sourceor the body, analogous to gasoline or a car).

mitoChonDrial

DysFunCtion anD

autism speCtrum

DisorDers:

a simpliFieDapproaCh

By DANIEL A. ROSSIgNOL, MD, FAAFP,1 AND R ICHAR D E. FRyE, MD, PHD2

aflitions: 1 International Child Development Resource Center, 3800 WestEau Gallie Blvd., Melbourne, FL, 32934, USA; and 2Division o Child andAdolescent Neurology and Childrens Learning Institute, Department o Pediatrics,University o Texas Health Science Center at Houston, Houston, TX, 77030, USA.



RichaRd E. FRyE, Md, Phd,received his MD/PhD romGeorgetown University. Hecompleted his pediatric residencyat University o Miami, anda child neurology residencyand ellowship in behavioralneurology and learningdisabilities at Childrens HospitalBoston. Dr. Frye is board

certifed in general pediatricsand in neurology with specialcompetency in child neurology.Currently at the University oTexas Health Science Centerat Houston, Dr. Frye studiesbrain structure and unction inneurodevelopmental disorders,mitochondrial dysunction andmetabolic disorders in autism,and novel autism treatments. Hehas published numerous papers

and book chapters on childrenwith autism.

AUTISMSCIENCEDIGEST:THEJOURNALOFAUTISMONEISSUE02REPRINTEDWITHPERMISSION www.autsmone.org



miTochondrial funcTionAs seen in Figure 1, the structure o the mitochondrion consists o outerand inner membranes, with a space (the intermembrane space) inbetween. The matrix is the innermost part o the mitochondria wheremany biochemical reactions occur, including the tricarboxylic acid(TCA) cycle, also known as the Krebs cycle or citric acid cycle. Theinner mitochondrial membrane contains fve complexes (known ascomplexes I through V) that make up the electron transport chain.On the bottom o the fgure, you can see glucose, which is eventuallybroken down into pyruvate through the process o glycolysis. Pyruvateis then transported into the mitochondria and eventually is brokendown into acetyl-CoA, which enters the TCA cycle. In the case omitochondrial dysunction, pyruvate transportation can be slowed,and, thereore, pyruvate can convert into lactate (also known as lacticacid) and alanine, leading to elevations in these markers.

Fatty acid metabolism is shown on the bottom right-hand corner

o the fgure. Short chain atty acids (SCFA) and medium chain attyacids (MCFA) can diuse directly into the mitochondria, whereaslong chain atty acids (LCFA) are transported into the mitochondria byattaching to carnitine, which shuttles these atty acids across the innerand outer mitochondrial membranes. Once inside the mitochondria,the atty acids, like pyruvate, are broken down and converted intoacetyl-CoA, which eeds into the TCA cycle. However, some o theelectrons released rom burning atty acids (atty acid oxidation)can eed into complex II through FADH2, bypassing complex I inthe process (which may partially explain why a ketogenic diet,which involves a high intake o ats, might be helpul or treatingmitochondrial dysunction).6

The three dotted lines with arrows coming o o the TCA cycle are

electrons (negatively charged particles) that are transerred throughNADH into complex I. Complex I then transers these electrons(depicted by the red dotted line) to coenzyme Q10 (CoQ10) whicin turn, transers the electrons to complex III. When the electronspass through complex I, NADH is converted to NAD+. Hydrogenprotons (positively charged hydrogen particles, H+) are pumpedrom the matrix (the innermost part o the mitochondria) through theinner membrane and into the intermembrane space, where theybuild up and orm an electrochemical gradient. The electrons thatpassed to complex III are now transerred by cytochrome C (CytC) to complex IV. This process also pumps more hydrogen protonsinto the intermembrane space through complexes III and IV. Duringthis process, oxygen is converted into water in complex IV (this ishow camels generate water rom at). The hydrogen protons inthe intermembrane space then diuse back into the matrix throughcomplex V (ATP synthase), and this generates ATP through a proce

known as oxidative phosphorylation.I the electron transport chain does not work properly (is

blocked), metabolites begin to back up and elevations can thenoccur in TCA cycle metabolites, atty acids, pyruvate, lactate (lacticacid) and alanine. Elevations in these metabolites are laboratorymarkers o mitochondrial dysunction.4 Generally, the higher theelevations and the more metabolites aected, the more likely thatmitochondrial dysunction exists.

clinical hisTory and laboraTory TesTingTo evaluate possible mitochondrial dysunction, it is important toexamine the patients clinical history. Sometimes there will be aamily history o mitochondrial disease. Other clinical history that is

f 1: Mtr struture ptws



oten observed in mitochondrial dysunction includes developmentalregression (loss o previously acquired skills), seizures, atigue

or lethargy, ataxia (lack o coordination o muscle movements),motor delays, gastrointestinal (GI) abnormalities (such as reux,constipation, dysmotility, diarrhea and inammation), andcardiomyopathy (signifcant heart problems). Ater a clinical historyand examination o the patient, laboratory testing can also be helpul(ideally perormed in the morning ater asting or 8-10 hours). Thelab tests in question are typically covered by insurance and oten canbe perormed by LabCorp or Quest Diagostics. It is important to havean experienced phlebotomist who is amiliar with these tests becausekeeping the tourniquet on during the blood draw or struggling duringthe blood draw can cause alse elevations in some laboratory tests.

The labs include: Lactate (lactic acid) Pyruvate Carnitine (ree and total) Acylcarnitine panel (atty acids attached to carnitine) Quantitative plasma amino acids Ubiquinone (also known as coenzyme Q10) Ammonia Creatine kinase (CK) AST and ALT CO2 and glucose

I the labs are abnormal, they may need to be repeated orconfrmation. I the labs are normal but mitochondrial dysunction isstill suspected, then repeating the labs when the child is sick or understress might help unmask and identiy mitochondrial dysunction.(Illness or stress will generally place mitochondria under more stressand increase dysunction.) Our recent publication on mitochondrialdysunction in children with ASD (available ree online) providesmore details.4

criTeria for miTochondrial disorderTo help identiy mitochondrial disorders, some investigators havedeveloped certain criteria. The use o a criterion helps physiciansand researchers to systematically evaluate and identiy mitochondrialproblems in individuals. Figure 2 (next page) reviews one suchcriterion or mitochondrial disorders (the Morava criteria).7Thiscriterion has 3 sections, ocusing on clinical signs and symptoms,

metabolic and imaging studies, and morphology. A total o 4 pointsare possible in each category. A total score o 8-12 is consistent with

defnite mitochondrial disorder, and a total score o 5-7 is consistentwith probable mitochondrial disorder. This tool can be utilized to helpdetermine i urther workup or mitochondrial dysunction is needed.

miTochondrial dysfuncTion and asdChildren with ASD are more likely to have defcits in their ability toproduce cellular energy than are typically developing children.3Cumulative damage and oxidative stress in mitochondria mightinuence both the onset and severity o autism, suggesting asignifcant link between autism and mitochondrial problems. Someindividuals with mitochondrial disease will have a genetic cause(termed primary mitochondrial disease). However, in our recentsystematic review and meta-analysis,4 most children (79%) whohad ASD and mitochondrial disease did not have a genetic reasonthat could explain their mitochondrial dysunction. Thereore, themitochondrial problems reported in these children may have beendue to a biochemical abnormality (termed secondary mitochondrialdisease).

secondary miTochondrial dysfuncTionand asdSeveral studies have documented a signifcantly lower meanglutathione (GSH) concentration8-10 and a lower mitochondrial GSHreserve11 in children with ASD compared to controls. GSH is themajor antioxidant in humans, and GSH depletion is associated with

impaired mitochondrial unction12

as well as increased ree radicalproduction.13 An example o a ree radical is an oxygen moleculethat has an unpaired electron (this ree radical is called a reactiveoxygen species), which can then remove an electron rom enzymesand DNA/RNA and cause damage. This damage is termedoxidative stress. Antioxidants can donate an electron to the reeradical to allow all o its electrons to be paired, which quenches theree radical and prevents oxidative stress.

O note, increased ree radicals can impair mitochondrialunction14 and may be particularly signifcant in individuals withASD since the latter have been shown, as a group, to be underhigher oxidative stress and have reduced levels o antioxidantscompared to typically developing children.8, 11, 15, 16 Furthermore,

GSH protects mitochondria against the adverse eects o TNF-,13 aproinammatory cytokine that can inhibit mitochondrial unction.17, 18

This might be particularly important since some studies have reportedhigher TNF- in lymphocytes,19 cerebral spinal uid,20 and brains21 o

In our recent sstematic review and meta-analsis, most children (79%) whohad ASD and mitochondrial disease did not have a enetic reason that could

explain their mitochondrial dsunction.

gSH protects mitochondria aainst the adverse efects o NF-, a proinammatorctokine that can inhibit mitochondrial unction. Tis miht be particularl important

since some studies have reported hiher NF- in lmphoctes, cerebral spinal uid,

and brains o individuals with ASD compared to controls.



f 2

mv t ., 2006 ct mt d

Section I: Clinical signs and symptoms (1-2 points per sign/symptom as indicated. 4 points max this section)

Section II: Metabolic/imaging studies(1-2 points per sign/symptom as indicated. 4 points max this section)

Section III: Morphology (muscle biopsy)(1-4 points per sign/symptom as indicated. 4 points max this section)

(a) Muscular presentation

Ophthalmoplegia (2 points) Facies myopathica

(b) CNS presentation

Developmental delay Loss o skills Stroke-like episodes Migraine

(c) Multisystem disease

Hematology GI tract Endocrine/growth

Exercise intolerance Muscle weakness

Seizures Myoclonus Cortical blindness Pyramidal signs

Heart Kidney Vision

Rhabdomyolysis Abnormal EMG

Extrapyramidal signs Brain stem involvement

Hearing Neuropathy Recurrent/amilial

Elevated lactate (2 points) Elevated lactate/pyruvate ratio Elevated alanine (2 points) Elevated CSF lactate (2 points)

Ragged red/blue fbers (4 points) Cox-negative fbers (4 points) Reduced COX staining (4 points)

Elevated CSF protein Elevated CSF alanine (2 points) Urinary tricarbon acid excretion (2 points) Ethylmalonic aciduria

Reduced SDH staining SDH positive blood vessels (2 points) Abnormal mitochondria/EM (2 points)

Stroke-like picture MRI Leigh syndrome/MRI (2 points) Elevated lactate/MRS

Referee: Morava, E., L. van den Heuvel, F. Hol, M.C. de Vries, M. Hogeveen, R.J. Rodenburg, et al. (2006).Mitochondrial disease criteria: diagnostic applications in children. Neurology, 67, 1823-6.

Please consult your physician for help with interpretation

1 mitochodial diod ulikly

2-4 poibl itochodial diod

5-7 pobabl itochodial diod

8-12 Dfit itochodial diod

score:

(4 points max this section) Total Points Section II:

(4 points max this section) Total Points Section III:

(2 points max this category) Points I(a)

II

III

I + II + III

(2 points max this category) Points I(b)

(3 points max this category) Points I(c)

(4 points max this section) Total Points Section I:

I

I(a) + I(b) + I(c)

Total Score



Tese ndins suest that mitochondria rom children with ASD ma be morevulnerable to damae rom environmental toxicants than mitochondria rom tpicall

developin children. In this context, exposures to environmental toxicants couldcontribute to secondar mitochondrial dsunction in some children with ASD.

individuals with ASD compared to controls.Additionally, in one study, exposure to ethylmercury (thimerosal)

led to a larger increase in ree radical generation and a greaterreduction in the ratio o reduced GSH to oxidized GSH in ASD cellscompared to control cells.11 These fndings suggest that mitochondriarom children with ASD may be more vulnerable to damage romenvironmental toxicants than mitochondria rom typically developingchildren.11 In this context, exposures to environmental toxicants couldcontribute to secondary mitochondrial dysunction in some childrenwith ASD.5, 22 For example, in vitro exposure to diesel exhaustparticles (DEP) has been shown to inhibit mitochondrial unction,23and elevated environmental concentrations o DEP have beenassociated with ASD.24 Other environmental toxicants that inhibitmitochondrial unction and have been associated with ASD includemercury,24-28 lead,29-32 cadmium,24, 33 PCBs,34, 35 and pesticides.36-39

Finally, Clostridia, an anaerobic, spore-orming Gram-positive rodbacterium, is known to produce propionic acid,40 and a derivativeo propionic acid recovered in the urine o ASD individuals hasbeen reported as a marker o Clostridia.41 A recent rat modelo ASD demonstrated that the administration o propionic acidinduced mitochondrial dysunction and led to certain behavioraland biochemical eatures o ASD such as repetitive behaviors, socialinteraction problems, hyperactivity, oxidative stress, lowered GSHlevels and altered carnitine levels.40, 42-44 Furthermore, signifcantlyelevated concentrations o Clostridia in the GI tract have been

reported in some ASD children compared to controls,45-47

withimprovements noted with vancomycin treatment in some children.48, 49Thereore, Clostridia may be a contributor to mitochondrial dysunctionin some children with ASD.

TreaTmenTs for miTochondrial dysfuncTionin asdSeveral studies have reported that nutritional supplementsand/or antioxidants may be benefcial in some children with ASDwho have mitochondrial dysunction. Six studies have reportedvarious improvements (including language and coordination)with the use o carnitine in children with ASD and mitochondrialdisease.1,8,50-53 Recently, another study reported improvements in

children with ASD using carnitine compared to placebo, althoughit was not reported i the children had concomitant mitochondrialdysunction.54 Along with carnitine, some investigators reportclinical improvements with coenzyme Q101,53,55 and high doses o

B vitamins, including thiamine or riboavin.1, 50, 53

Cerebral olatedefciency (CFD) has been described in one child with ASD andmitochondrial disease.56 In some studies, treatment with olinicacid and a milk-ree diet has been reported to result in signifcantimprovements in ASD symptoms in children with CFD.57, 58

Treatment o mitochondrial dysunction also consists o specifcprecautions to avoid prolonged asting, implement dietaryrecommendations (ensuring an adequate number o calories),59avoid certain medications,60 adopt anesthesia precautions orsurgery, and avoid inections61 (i possible). Additional treatmentrecommendations pertain to antipyretic (ever) therapy, intravenoushydration, and nutritional supplements during acute illnesses.Furthermore, because hypoxia can impair mitochondrial unction,62

increasing oxygen delivery to dysunctional mitochondria throughhyperbaric oxygen therapy (HBOT) might aid in improvingmitochondrial unction.63-67 In one animal study, HBOT was reportedto activate mitochondrial DNA transcription and replication, andincrease the biogenesis o mitochondria in the brains o animals.68Clinically, some patients treated by Dr. Rossignol who have ASDand mitochondrial disease have improved with the use o HBOTprovided at low atmospheric pressure (1.3 to 1.5 atmospheres),including one child whose improvements in mitochondrial unctionwere documented by repeat muscle biopsy. However, increasingoxygen delivery to mitochondria can increase oxidative stress; theHBOT pressure should thereore be careully monitored under the

guidance o an experienced physician, and generally low levels opressure (1.3 to 1.5 atmospheres) and lower oxygen concentrations(~24%) should be used initially.

69, 70 Further studies examining thesetreatments or mitochondrial dysunction in ASD are needed.

miTochondrial dysfuncTion and asd:implicaTions for The fuTureThere is much still to be learned regarding the biology omitochondrial disease and ASD. Evidence has rapidly accumulatedthat clearly supports an association between these two seeminglydierent disorders. Although some children with ASD have a geneticcause or mitochondrial dysunction, many will have a secondarycause. It appears that at least a subpopulation o children with ASD

has mitochondrial disease as the core biological lesion contributingto their ASD and associated comorbidities. Further studies in the feldo mitochondrial medicine may one day help unlock the mysteriesthat defne ASD.

Clinicall, some patients treated b Dr. Rossinol who have ASD and mitochondrialdisease have improved with the use o HBO provided at low atmospheric pressure(1.3 to 1.5 atmospheres), includin one child whose improvements in mitochondrial

unction were documented b repeat muscle biops.


8/8

reFerenCes

1. Poling JS, Frye RE, Shoner J, Zimmerman AW.Developmental regression and mitochondrial dysunction in achild with autism.J Child Neurol. 2006;21(2):170-2.

2. Haas RH. Autism and mitochondrial disease. Dev Disabil ResRev. 2010;16(2):144-53.

3. Frye RE, Rossignol DA. Mitochondrial dysunction canconnect the diverse medical symptoms associated with autismspectrum disorders. Pediatr Res. 2011 May;69(5 Pt 2):41R-7R.

4. Rossignol DA, Frye RE. Mitochondrial dysunction in autismspectrum disorders: a systematic review and meta-analysis.MolPsychiatry. 2011 Jan 25.

5. Rossignol DA, Bradstreet JJ. Evidence o mitochondrialdysunction in autism and implications or treatment.Am JBiochem Biotech. 2008;4(2):208-17.

6. Ahola-Erkkila S, Carroll CJ, Peltola-Mjosund K, Tulkki V,Mattila I, Seppanen-Laakso T et al. Ketogenic diet slows downmitochondrial myopathy progression in mice. Hum Mol Genet.2010;19(10):1974-84.

7. Morava E, van den Heuvel L, Hol F, de Vries MC,Hogeveen M, Rodenburg RJ et al. Mitochondrial diseasecriteria: diagnostic applications in children. Neurology.2006;67(10):1823-6.

8. Pastural E, Ritchie S, Lu Y, Jin W, Kavianpour A, Khine Su-Myat K et al. Novel plasma phospholipid biomarkers o autism:mitochondrial dysunction as a putative causative mechanism.Prostaglandins Leukot Essent Fatty Acids. 2009;81(4):253-64.

9. James SJ, Cutler P, Melnyk S, Jernigan S, Janak L, GaylorDW et al. Metabolic biomarkers o increased oxidative stressand impaired methylation capacity in children with autism.Am JClin Nutr. 2004;80(6):1611-7.

10. James SJ, Melnyk S, Jernigan S, Cleves MA, HalstedCH, Wong DH et al. Metabolic endophenotype and relatedgenotypes are associated with oxidative stress in childrenwith autism.Am J Med Genet B Neuropsychiatr Genet.2006;141(8):947-56.

11. James SJ, Rose S, Melnyk S, Jernigan S, Blossom S, Pavliv Oet al. Cellular and mitochondrial glutathione redox imbalance inlymphoblastoid cells derived rom children with autism. FASEB J.2009;23(8):2374-83.

12. Vali S, Mythri RB, Jagatha B, Padiadpu J, Ramanujan KS,Andersen JK et al. Integrating glutathione metabolism andmitochondrial dysunction with implications or Parkinsonsdisease: a dynamic model. Neuroscience . 2007;149(4):917-30.

13. Fernandez-Checa JC, Kaplowitz N, Garcia-Ruiz C, ColellA, Miranda M, Mari M et al. GSH transport in mitochondria:deense against TNF-induced oxidative stress and alcohol-induced deect. Am J Physiol. 1997;273(1 Pt 1):G7-17.

14. Wallace DC. Mitochondrial diseases in man and mouse.

Science. 1999;283(5407):1482-8.15. Chauhan A, Chauhan V. Oxidative stress in autism.Pathophysiology. 2006;13(3):171-81.

16. James SJ, Melnyk S, Fuchs G, Reid T, Jernigan S, Pavliv Oet al. Eicacy o methylcobalamin and olinic acid treatment onglutathione redox status in children with autism.Am J Clin Nutr.2009;89(1):425-30.

17. Samavati L, Lee I, Mathes I, Lottspeich F, Huttemann M.Tumor necrosis actor alpha inhibits oxidative phosphorylationthrough tyrosine phosphorylation at subunit I o cytochrome coxidase.J Biol Chem. 2008;283(30):21134-44.

18. Vempati UD, Diaz F, Barrientos A, Narisawa S, Mian AM,Millan JL et al. Role o cytochrome C in apoptosis: increasedsensitivity to tumor necrosis actor alpha is associated withrespiratory deects but not with lack o cytochrome C release.

Mol Cell Biol. 2007;27(5):1771-83.

19. Malik M, Sheikh AM, Wen G, Spivack W, Brown WT, LiX. Expression o inlammatory cytokines, Bcl2 and cathepsin Dare altered in lymphoblasts o autistic subjects. Immunobiology.2010 Jan-Feb;216(1-2):80-5.

20. Chez MG, Dowling T, Patel PB, Khanna P, Kominsky M.Elevation o tumor necrosis actor-alpha in cerebrospinal luid oautistic children. Pediatr Neurol. 2007;36(6):361-5.

21. Li X, Chauhan A, Sheikh AM, Patil S, Chauhan V, Li XM etal. Elevated immune response in the brain o autistic patients.JNeuroimmunol. 2009;207(1-2):111-6.

22. Zecavati N, Spence SJ. Neurometabolic disorders anddysunction in autism spectrum disorders. Curr Neurol NeurosciRep. 2009;9(2):129-36.

23. Hiura TS, Li N, Kaplan R, Horwitz M, Seagrave JC, NelAE. The role o a mitochondrial pathway in the induction oapoptosis by chemicals extracted rom diesel exhaust particles.

J Immunol. 2000;165(5):2703-11.

24. Windham GC, Zhang L, Gunier R, Croen LA, Grether JK.Autism spectrum disorders in relation to distribution o hazardousair pollutants in the San Francisco bay area. Environ HealthPerspect. 2006;114(9):1438-44.

25. Palmer RF, Blanchard S, Stein Z, Mandell D, Miller C.Environmental mercury release, special education rates, andautism disorder: an ecological study o Texas. Health Place.2006;12(2):203-9.

26. Fowler BA, Woods JS. Ultrastructural and biochemicalchanges in renal mitochondria during chronic oral methylmercury exposure: the relationship to renal unction. Exp MolPathol. 1977;27(3):403-12.

27. Shenker BJ, Guo TL, O I, Shapiro IM. Induction o apoptosisin human T-cells by methyl mercury: temporal relationshipbetween mitochondrial dysunction and loss o reductivereserve. Toxicol Appl Pharmacol. 1999;157(1):23-35.

28. Palmer RF, Blanchard S, Wood R. Proximity to point sourceso environmental mercury release as a predictor o autismprevalence. Health Place. 2009;15(1):18-24.

29. Lidsky TI, Schneider JS. Autism and autistic symptomsassociated with childhood lead poisoning.J Applied Research.2005;5(1):80-7.

30. Goyer RA. Toxic and essential metal i nteractions.Annu RevNutr. 1997;17:37-50.

31. Cohen DJ, Johnson WT, Caparulo BK. Pica and elevatedblood lead level in autistic and atypical children. Am J DisChild. 1976;130(1):47-8.

32. Campbell M, Petti TA, Green WH, Cohen IL, GenieserNB, David R. Some physical parameters o young autisticchildren. J Am Acad Child Psychiatry. 1980;19(2):193-212.

33. Pourahmad J, Mihajlovic A, OBrien PJ. Hepatocyte lysisinduced by environmental metal toxins may involve apoptoticdeath signals initiated by mitochondrial injury.Adv Exp MedBiol. 2001;500:249-52.

34. Wong PW, Garcia EF, Pessah IN. Ortho-s ubstitutedPCB95 alters intracellular calcium signaling and causes c ellularacidiication in PC12 cells by an immunophilin-dependentmechanism. J Neurochem. 2001;76(2):450-63.

35. Edelson SB, Cantor DS. The neurotoxic etiology o theautistic spectrum disorders: a replication study. Toxicol IndHealth. 2000;16(6):239-47.

36. Eskenazi B, Marks AR, Bradman A, Harley K, Barr DB,Johnson C et al. Organophosphate pesticide exposure andneurodevelopment in young Mexican-American children.Environ Health Perspect. 2007;115(5):792-8.

37. Yamano T, Morita S. Eects o pesticides on isolated rathepatocytes, mitochondria, and microsomes II.Arch EnvironContam Toxicol. 1995;28(1):1-7.

38. Roberts EM, English PB, Grether JK, Windham GC,Somberg L, Wol C. Maternal residence near agriculturalpesticide applications and autism spectrum disorders amongchildren in the Caliornia Central Valley. Environ HealthPerspect. 2007;115(10):1482-9.

39. Rauh VA, Garinkel R, Perera FP, Andrews HF, HoepnerL, Barr DB et al. Impact o prenatal chlorpyrios exposure onneurodevelopment in the irst 3 years o lie among inner- citychildren. Pediatrics . 2006 ;118(6): e1845- e1859.

40. MacFabe DF, Cain DP, Rodriguez-Capote K, FranklinAE, Homan JE, Boon F et al. Neurobiological eects ointraventricular propionic acid in rats: possible role o shortchain atty acids on th e pathogenesis and characteristics oautism spectrum disorders. Behav Brain Res. 2007;176(1):149-69.

41. Shaw W. Increased urinary excretion o a3-(3-hydroxyphenyl)-3-hydroxypropionic acid (HPHPA), anabnormal phenylalanine metabolite o Clostridia spp. in thegastrointestinal tract, in urine samples rom patients with autismand schizophrenia. Nutr Neurosci. 2010;13(3):135-43.

42. MacFabe DF, Rodrguez-Capote K, Homan JE, FranklinAE, Mohammad-Ase Y, Taylor AR et al. A novel rodent modelo autism: intraventricular inusions o propionic acid increaselocomotor activity and induce neuroinlammation and oxidative

stress in discrete regions o adult rat brain.Am J BiochemBiotech. 2008;4(2):146-66.

43. Shultz SR, MacFabe DF, Ossenkopp KP, Scratch S,Whelan J, Taylor R et al. Intracerebroventricular injection opropionic acid, an enteric bacterial metabolic end-product,impairs social behavior in the rat: implications or an animalmodel o autism. Neuropharmacology. 2008;54(6):901-11.

44. Thomas RH, Foley KA, Mepham JR, Ticheno LJ,Possmayer F, MacFabe DF. Altered brain phospholipid andacylcarnitine proiles in propionic acid inused rodents: urtherdevelopment o a potential model o autism s pectrum disorders.

J Neurochem. 2010;113(2):515-29.

45. Finegold SM, Molitoris D, Song Y, Liu C, Vaisanen ML,Bolte E et al. Gastrointestinal microlora studies in late-onsetautism. Clin Infect Dis. 2002;35(Suppl 1):S6 -S16.

46. Parracho HM, Bingham MO, Gibson GR, McCartneyAL. Dierences between the gut microlora o children withautistic spectrum disorders and that o healthy children.J Med

Microbiol. 2005;54(Pt 10):987-91.

47. Song Y, Liu C, Finegold SM. Real-time PCR quantitation oclostridia in eces o autistic children.Appl Environ Microbiol. 2004;70(11):6459-65.

48. Bolte ER. Autism and Clostridium tetani.Med Hypotheses. 1998;51(2):133-44.

49. Sandler RH, Finegold SM, Bolte ER, Buchanan CP,Maxwell AP, Vaisanen ML et al. Short-term beneit rom oralvancomycin treatment o regressive-onset autism.J Child Neurol.2000;15(7):429-35.

50. Filipek PA, Juranek J, Smith M, Mays LZ, Ramos ER, BocianM et al. Mitochondrial dysunction in autistic patients with 15qinverted duplication.Ann Neurol. 2003;53(6):801-4.

51. Gargus JJ, Lerner MA. Familial autism with primary carnitinedeiciency, sudden death, hypotonia and hypochromic anemia.

Am J Hum Genet. 1997;61:A98.

52. Gargus JJ, Imtiaz F. Mitochondrial energy-deicientendophenotype in autism.Am J Biochem Biotech. 2008;4(2):198-207.

53. Ezugha H, Goldenthal M, Valencia I, Anderson CE, LegidoA, Marks H. 5q14.3 deletion maniesting as mitochondrialdisease and autism: case report. J Child Neurol. 2010Oct;25(10):1232-5.

54. Geier DA, Kern JK, Davis G, King PG, Adams JB, Young JLet al. A prospective double-blind, randomized clinical trial olevocarnitine to treat autism spectrum disorders.Med Sci Monit.2011;17(6):PI15-23.

55. Tsao CY, Mendell JR. Autistic disorder in 2 children withmitochondrial disorders.J Child Neurol. 2007;22(9):1121-3.

56. Shoner J, Hyams L, Langley GN, Cossette S, MylacraineL, Dale J et al. Fever plus mitochondrial disease could be riskactors or autistic regression. J Child Neurol. 2010;25(4):429-34.

57. Moretti P, Sahoo T, Hyland K, Bottiglieri T, Peters S, delGaudio D et al. Cerebral olate deiciency with developmentaldelay, autism, and response to olinic acid. Neurology.2005;64(6):1088-90.

58. Ramaekers VT, Sequeira JM, Blau N, Quadros EV. Amilk-ree diet downregulates olate receptor autoimmunity incerebral olate deiciency syndrome. Dev Med Child Neurol.2008;50(5):346-52.

59. Morava E, Rodenburg R, van Essen HZ, De Vries M,Smeitink J. Dietary intervention and oxidative phosphorylationcapacity.J Inherit Metab Dis. 2006;29(4):589.

60. Neustadt J, Pieczenik SR. Medication-inducedmitochondrial damage and disease.Mol Nutr Food Res. 2008;52(7):780-8.

61. Edmonds JL, Kirse DJ, Kearns D, Deutsch R, SpruijtL, Naviaux RK. The otolaryngological maniestations omitochondrial disease and the risk o neurodegeneration

with inection.Arch Otolaryngol Head Neck Surg.2002;128(4):355-62.

62. Magalhaes J, Ascensao A, Soares JM, FerreiraR, Neuparth MJ, Marques F et al. Acute and severehypobaric hypoxia increases oxidative stress and impairsmitochondrial unction in mouse skeletal muscle.J Appl Physiol.2005;99(4):1247-53.

63. Daugherty WP, Levasseur JE, Sun D, Rockswold GL,Bullock MR. Eects o hyperbaric oxygen therapy oncerebral oxygenation and mitochondrial unction ollowingmoderate lateral luid-percussion injury in rats. J Neurosurg.2004;101(3):499-504.

64. Dave KR, Prado R, Busto R, Raval AP, Bradley WG,Torbati D et al. Hyperbaric oxygen therapy protects againstmitochondrial dysunction and delays onset o motor neurondisease in Wobbler mice. Neuroscience . 2003;120(1):113-20.

65. Boveris A, Chance B. The mitochondrial generation ohydrogen peroxide. General properties and eect o hyperbaricoxygen. Biochem J. 1973;134(3):707-16.

66. Gosalvez M, Castillo Olivares J, De Miguel E, BlancoM, Figuera D. Mitochondrial respiration and oxidativephosphorylation during hypothermic hyperbaric hepaticpreservation.J Surg Res. 1973;15(5):313-8.

67. Bar-Sagie D, Mayevsky A, Bartoov B. Eects o hyperbaricoxygenation on spermatozoan motility driven by mitochondrialrespiration.J Appl Physiol. 1981;50(3):531-7.

68. Gutsaeva DR, Suliman HB, Carraway MS, Demchenko IT,Piantadosi CA. Oxygen-induced mitochondrial biogenesis in therat hippocampus. Neuroscience . 2006;137(2):493-504.

69. Rossignol DA, Rossignol LW, Smith S, Schneider C,Logerquist S, Usman A et al. Hyperbaric treatment or childrenwith autism: a multicenter, randomized, double-blind, controlledtrial. BMC Pediatr. 2009;9:21.

70. Rossignol DA, Rossignol LW, James SJ, Melnyk S, MumperE. The eects o hyperbaric oxygen therapy on oxidative stress,inlammation, and symptoms in children with autism: an open-label pilot study. BMC Pediatr. 2007;7(1):36.

Documents

Mitochondrial Dysfunction and Autism Spectrum Disorders: A Simplified Approach by Daniel Rossignol, MD, & Richard Frye, MD, PhD