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Biomarkers of Abnormal Energy Metabolism in Children with Autism

Biomarkers of Abnormal Energy Metabolism in Children with Autism. Richard E. Frye, M.D., Ph.D. Assistant Professor of Pediatrics and Neurology University of Texas Health Science Center. Guiding Principles of A New Paradigm . Autism, although not a medical diagnosis, is biologically based

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Biomarkers of Abnormal Energy Metabolism in Children with Autism

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  1. Biomarkers of Abnormal Energy Metabolism in Children with Autism Richard E. Frye, M.D., Ph.D. Assistant Professor of Pediatrics and Neurology University of Texas Health Science Center

  2. Guiding Principles of A New Paradigm • Autism, although not a medical diagnosis, is biologically based • The rise in Autism cases is due to a complex interaction between genetics and environment. • Autism is a systemic disorder with primary neurological manifestations.

  3. Guiding Principles of A New Paradigm • Based on biological markers, subpopulations must be defined to guide proper basic science, epidemiology, diagnosis, treatment, and prevention. • Epidemiology and genetics studies have failed to identify a basic cause of Autism because the clinicians have not properly defined the endophenotypes/subpopulations

  4. The Mighty Mitochondria

  5. The Mighty Mitochondria

  6. The Mighty Mitochondria • Key Pathway for Processing Glucose, the body’s primary energy source • Mitochondrial Dysfunction causes build up of potentially toxic acids • Mitochondrial Dysfunction can cause depletion of glutamate, a key neurotransmitter important in learning

  7. The Mighty Mitochondria • The final step for making energy • Needs Co-Q10

  8. The Mighty Mitochondria Dysfunction of the Electron Transport Chain Results in build-up of organic acids

  9. Mitochondrial disease • Young field, 1988 DC Wallace, • Extremely clinical symptoms • Neurological Disease • Gastrointestinal Disease • Immune Dysfunction • Extremely complex genetics • Two Types of DNA • mtDNA and nuclear DNA • Not just powerhouse—programmed (apoptotic) cell death

  10. Mitochondrial Dysfunction Important in Many Diseases

  11. New or Underrecognized? • Dr. Mary Coleman, Georgetown U 1985 • 4 of 80 (5%) of patients with lactic acidemia • 1 of 4 pts with regression • Propose primary defect in carbohydrate metabolism, pyruvate dehydrogenase • Speculate that Ketogenic diet may be helpful

  12. Can Autism Be A Mitochondrial Disease? • 3+ systems involved, fluctuating symptoms, intolerance to fasting/dietary changes • Nervous system, muscle, gut, immune system involvement—most energy dependent tissues • Response to carbohydrate exclusive diets (GCFC, ketogenic, specific carbohydrate) • High heritability by family history with near failure of classic Mendelian genetics to explain • Spectrum of severity

  13. Can Autism Be A Mitochondrial Disease? • Proposed environmental precipitants may selectively injury metabolically susceptible individuals. • Data analogous to Parkinson’s disease research. • Environmental/Epigenetic toxins act via mitochondrial mechanism • Other non-mitochondrial genetic lesions which increase oxidative stress increase ASD risk • GSTP1*A haplotype Williams, T.A., et al., Risk of autistic disorder in affected offspring of mothers with a glutathione S-transferase P1 haplotype. Arch Pediatr Adolesc Med, 2007. 161(4): p. 356-61. • James, S.J., et al., Metabolic endophenotype and related genotypes are associated with oxidative stress in children with autism. Am J Med Genet B Neuropsychiatr Genet, 2006. 141(8): p. 947-56.

  14. Can Autism Be A Mitochondrial Disease? Divergent Evidence Multiple mitochondrial lesions appear to produce an ASD phenotype

  15. Divergent Evidence • 15q inverted duplication Filipek, P.A., et al., Mitochondrial dysfunction in autistic patients with 15q inverted duplication. Ann Neurol, 2003. 53(6): p. 801-4. PRADER WILLI TYPE MUTATION • A3243G mtDNA mutation and mtDNA depletion. Pons, R., et al., Mitochondrial DNA abnormalities and autistic spectrum disorders. J Pediatr, 2004. 144(1): p. 81-5. MIDD MELAS MUTATION • mitochondrial DNA G8363A transfer RNA(Lys) mutation. Graf, W.D., et al., Autism associated with the mitochondrial DNA G8363A transfer RNA(Lys) mutation. J Child Neurol, 2000. 15(6): p. 357-61. MERRF, LEIGH, CARDIOMYOPATHY, ATAXIA LIPOMA SYNDROME • Rett Syndrome MECP2 knockout. Kriaucionis, S., et al., Gene expression analysis exposes mitochondrial abnormalities in a mouse model of Rett syndrome. Mol Cell Biol, 2006. 26(13): p. 5033-42. RETT SYNDROME

  16. Empirical Evidence • Filipek, P.A., et al., Relative carnitine deficiency in autism. J Autism Dev Disord, 2004. 34(6): p. 615-23. NONSPECIFIC MITO DYSFUNCTION • Poling, J.S., et al., Developmental regression and mitochondrial dysfunction in a child with autism. NONSPECIFIC MITO DYSFUNCTION • J Child Neurol, 2006. 21(2): p. 170-2. Tsao, C.Y. and J.R. Mendell, Autistic disorder in 2 children with mitochondrial disorders. J Child Neurol, 2007. 22(9): p. 1121-3. CO Q10 DEFICIENCY AND THE OTHER NONSPECIFIC RC DYSFUNCTION II/III & IV

  17. Mitochondrial Dysfunction emerging as most common medical condition associated with autism. • Of 159 autism patients in one autism clinic, 38% had non-specific biochemical abnormalities. Poling et al. Developmental regression and mitochondrial dysfunction in a child with autism. J Child Neurol, 2006. 21(2): p. 170-2. • 7.2% of patients with Autism could be classified as having a ‘definite’ mitochondrial respiratory chain disorder and 20% had elevated serum lactic acid Oliveira, G., et al., Mitochondrial dysfunction in autism spectrum disorders: a population-based study. Dev Med Child Neurol, 2005. 47(3): p. 185-9. • 2nd study 4%; Oliveira, G., et al., Epidemiology of autism spectrum disorder in Portugal: prevalence, clinical characterization, and medical conditions. Dev Med Child Neurol, 2007. 49(10): p. 726-33.

  18. Mitochondrial Dysfunction emerging as most common medical condition associated with autism. • 36% of 100 autism patients have total carnitine levels 1SD below mean control, pattern suggestive mild mitochondrial dysfunction. Filipek, P.A., et al., Relative carnitine deficiency in autism. J Autism Dev Disord, 2004. 34(6): p. 615-23. • 65% of autism pts referred for mitochondrial evaluation to specialty clinic positive for OxPhos disorder on muscle biopsy. Shoffner, J., L.C. Hyams, and G.N. Langley, Oxidative Phosphorylation (OXPHOS) Defects in Children with Autistic Spectrum Disorders, in AAN. 2008: Chicago.

  19. Autistic Spectrum Cases--AST vs. Age AST declines by 3.2 IU/L/10years JS Poling Johns Hopkins Neurology Grand Rounds 6/21/2001 Metabolic Disturbances in Autistic Children: The KKI Experience from 1995-2001

  20. Autistic Spectrum--CPK 7 of 14 elevated 50% Mean 168 N=14 IU/L Age (years)

  21. Mmol/L (40%) Age (years) Autistic Spectrum—Lactate

  22. Biomarkers of Abnormal Energy Metabolism in Children with Neurodevelopmental Disorders A review of metabolic studies from 133 consecutive patients evaluated in a medically-based autism clinic

  23. Pyruvic Acid CMA MitoMet mtDNA point mutations Start Supplements L-Carnitine (Carnitor) Ubiquinol (Douglas Labs) B-Complex (Supra-Nu Thera) Suspect Mitochondrial Disorder Morning Fasting CMP Lactic Acid Amino Acids Ammonia Acyl-Carnitine Creatine Kinase Urine Organic Acids CO2 LFTs Glucose No Diagnosis If Lab Abnormal Repeat to Confirm Muscle Biopsy Histology Electron Microscopy Electron Transport Chain Studies mtDNA Content Studies Suspect Fatty Acid Disorder RBC Zinc & Copper, Biotin Triglyceride & Cholesterol Panel Urine Acyl-Glycine & Ketones More Specific Diagnosis Testing of Specific Genes mtDNA sequencing No Diagnosis Skin Biopsy with Fatty-acid oxidation and electron transport chain studies, MitoMet Specific Therapy

  24. 6 Biomarkers Reviewed 4 Groups with high prevalence Identified Lactate, Alanine-to-Lysine & Acyl-Carnitine 34.3% with AST 53.0%

  25. Symptoms reviewed for 4 Groups with high prevalence Lactate -- High Rate of Global Delay Alanine-to-Lysine – High Rate of Epilepsy Acyl-Carnitine -- High Rate of Regression

  26. Elevated Lactate Group

  27. Elevated AST Group

  28. Alanine to Lysine Elevation Group

  29. Acyl-Carnitine Elevation Group

  30. Treatment of Mitochondrial Disease

  31. Treatment of Mitochondrial Disease • Carbohydrate exclusive diets • GCFC • Ketogenic Diet • Specific carbohydrate diet • Avoid Fasting and Dehydration • Avoid Sleep Deprivation • Future Therapies

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