The history of the mitochondrial medicine society and advancement of mitochondrial global networks for international collaboration

Abstracts

diagnoses such as cerebral palsy, few tools are available and relevant to children with complex metabolic pathologies such as mitochondrial disorders. The inability to assess and serve the undiagnosed population leads to dump diagnoses, operationally defined here as the diagnosis that most closely fits and provides for services and reimbursement by third party payers. Moreover, patients with multisystem system diagnoses are referred to many health care providers for treatment, but the responsibility for centralized data collection from all providers is undefined. Clinical indicators (cluster of signs and symptoms) that may be exhibited are currently not compiled in any national database or referenced in any literature. The possibility of grouping according to these indicators is plausible as a mechanism of organization, but is not yet in place for undiagnosed children with multisystem disorders. A tool to assist health care professionals with identifying clusters of clinical indicators could benefit many individuals with complex metabolic disorders. Expanding the scope of identification beyond the physician realm may ultimately serve all aspects of patient care, and make the task of diagnosis more expeditious with appropriate referrals. Ultimately, both providers and patients would benefit with a honed diagnostic paradigm. doi:10.1016/j.mito.2015.07.107

Abstract 103 Mitochondrial respiratory chain disorders in the old order Amish population Presenter: Amy Goldstein Amy Goldsteina, Lina Ghaloul-Gonzaleza,1, Steven Dobrowolskib, Cate Walsh Vockleya, Afifa Iranic, Bess Wayburnc, D. Holmes Mortond, Jerry Vockleya,c a Department of Pediatrics, University of Pittsburgh, School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA b Pathology Department, University of Pittsburgh, Pittsburgh, PA, USA c Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA d Clinic for Special Children, USA 1 The first co-authors have contributed equally to the abstract. Abstract: Mitochondrial DNA (mtDNA) mutations have not previously been reported in any Old Order Amish community. We describe here an Amish family with the MTTL1 mitochondrial gene mutation m.3243ANG. A second patient with a m.13513GNA (D393N) mutation has also been diagnosed. These mutations classically cause MELAS syndrome (Mitochondrial Encephalopathy, Lactic Acidosis and Strokelike episodes). We identified the first mutation in a young woman from the Mercer County Amish community at age 15 years. She had a history of developmental delay, short stature, hearing loss, fatigability, and poor appetite. She presented acutely with vomiting, altered mental status, status epilepticus, and lactic acidosis. MRI of the brain showed a small, focal, left occipital lobe infarct. She subsequently developed other strokelike episodes in the left occipital and temporal areas. Molecular testing revealed 74% heteroplasmy in saliva for the MELAS 3243ANG mutation. Several members of the extended maternal pedigree exhibit variable clinical problems including developmental delay, mild hypotonia, hearing loss, renal failure, migraine headaches, adult onset diabetes mellitus and recurrent miscarriages, but have never had genetic evaluations. Targeted assessment for the m.3243ANG mutation using high resolution melt profiling (HRM) on urine and blood spot samples was performed on 15 individuals from this family, 13 adults and 2 children. Saliva and buccal mucosa cells were also tested in some patients. Detailed pedigree, clinical symptoms and physical findings were collected at a family meeting. The mutation was found in 11 adults and 2 children. Heteroplasmy levels varied in family members and tissue

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sample tested, typically higher in urine sediment cells than in peripheral blood cells. In five individuals with testing of buccal mucosa cells collected by swab, heteroplasmy level was lower and more similar between saliva and blood compared to urine sediment. The degree of heteroplasmy in the 2 year old was similar in blood and urine. The decline in the mutation rate in blood with time has previously been observed (McDonnell et al., 2004; Rahman et al. 2001; and t' Hart et al. 1996). The degree of heteroplasmy in the urine sediment cells correlated more closely with clinical severity, concurring with a previous description of urine sediment as the best non-invasive sample in which to measure m.3243ANG heteroplasmy (Whittaker RG, et al. 2009) A patient from a second Amish family was diagnosed with MELAS/ Leigh overlap syndrome resulting from the mitochondrial mutation m.13513GNA(D393N) in the ND5 subunit of respiratory chain complex I, with blood heteroplasmy level of 2% and urine heteroplasmy level of 43%. The proband was diagnosed at 12 years of age with an acute stroke after a history of developmental delay. His lactate was mildly increased. He has subsequently had recurrent strokes and developed Leigh-like basal ganglia and brainstem lesions with progressive spasticity, dysphagia, and weakness. No siblings were affected and the mother tested negative for the mutation in blood and urine. A third patient in this Amish community has been diagnosed with an autosomal recessive respiratory chain disorder due a homozygous deletion in the NDUFAF2 gene, which was in one of the 9 areas of homozygosity detected on SNP microarray. He had a history of developmental delay, nystagmus and hypotonia, subsequently admitted to the hospital with a viral illness, with progressive respiratory failure. He required intubation and his MRI revealed Leigh-like lesions. He could not be weaned from the ventilator and 3 weeks later his repeat MRI showed worsening of lesions with infarction of cerebellar white matter. He remained unresponsive and fulfilled brain death criteria, ultimately dying after discontinuation of life support. Our findings represent the first report of mitochondrial respiratory chain disorders in the Amish community, and suggest that it may be under diagnosed. Testing for these disorders is warranted in Amish individuals with suggestive symptoms. doi:10.1016/j.mito.2015.07.108

Abstract 104 The history of the mitochondrial medicine society and advancement of mitochondrial global networks for international collaboration Presenter: Amy Goldstein Amy Goldstein Department of Pediatrics, University of Pittsburgh, School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA Abstract: The Mitochondrial Medicine Society (MMS) was founded in 2000 by Drs. Richard Haas and Robert Naviaux. Currently, the MMS represents an international group of researchers and clinicians working towards improved diagnosis, management, and treatment of mitochondrial diseases. The MMS maintains an active website www.mitosoc.org which includes important publications and resources. In 2014, the MMS Board revised the mission statement: “Advancing education, research, and global collaboration in clinical mitochondrial medicine”, inspired by our international colleagues and the realization that global collaboration will be necessary to power clinical trials to reach statistical significance. MitoGlobal or the ‘Mitochondrial Global Network’ has been in discussion for several years at the Mitochondrial Physiology Society (MiP) (www.mitophysiology.org) meetings, spearheaded by Dr. Erich Gnaiger. The purpose of MitoGlobal includes forming a network of national and international mitochondrial societies; organizers of national and international mitochondrial conferences

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Abstracts

and workshops; scientific, medical and public opinion leaders in mitochondrial research and medicine; mitochondrial network initiatives; and mitochondrial centers of excellence. The aims of MitoGlobal include: promoting mitochondrial medicine, mitochondrial health care, preventive and protective medicine; improving communication between mitochondrial societies, and integrating with general scientific societies; providing a comprehensive list of mitochondrial communications networks, mitochondrial network projects; providing a comprehensive list of mitochondrial centers of excellence; and establishing and maintaining contact with patient organizations. Mitochondrial medicine in the United States has been challenged by the large geographical area, lack of clinicians with expertise, and health insurance. International examples of mitochondrial medicine networks can be found in the United Kingdom (NHS England) with collaborating sites in Newcastle/London/Oxford with the main objective of the service to improve the diagnosis and clinical care for patients with rare mitochondrial diseases. Diseases such as cystic fibrosis found improvements in survival outcomes by creating standardized care, a patient registry, and a foundation which oversees that clinical care standards are maintained. Mitochondrial medicine in the US has improved by the creation of NAMDC (North American Mitochondrial Disease Consortium patient registry and Biorepository) and the UMDF Patient Registry. In addition, the National Institute for Neurological Disorders and Stroke published Common Data Elements (CDEs) for Mitochondrial Disease (http://www.commondataelements.ninds.nih.gov/ MITO.aspx#tab=Data_Standards) recently, helping to standardize outcome measures for clinical trials. In order to foster international collaboration, a live Google map will be maintained by the MMS which will include: international clinicians, medicine networks, patient support groups. https:// www.google.com/maps/d/edit?mid=zCp3eT4omt2w.kZbWhUxIlrFk. doi:10.1016/j.mito.2015.07.109

Abstract 105 A case of canine mitochondrial myopathy with cardiomyopathy Presenter: Richard H. Haas G. Diane Sheltona, Ling Guoa, Thuy Lec,d, Robert K. Naviauxa,b,c, Kathy Wrighte, Richard H. Haasc,d a Dept. of Pathology, University of California San Diego, La Jolla, CA, USA b Dept. of Medicine, University of California San Diego, La Jolla, CA, USA c Dept. of Pediatrics, University of California San Diego, La Jolla, CA, USA d Dept. of Neurosciences, University of California San Diego, La Jolla, CA, USA e MedVet Medical and Cancer Centers for Pets, Cincinnati, OH, USA Abstract: Canine examples of mitochondrial disease are rare. A 3-month-old F Dachsund puppy presented for evaluation of a heart murmur. A variable intensity, right basilar, systolic murmur ranged from a 2/6 at slower heart rates to 4/6 at higher heart rates. Echocardiogram demonstrated severe concentric hypertrophy with normal systolic function and dynamic subaortic stenosis at heart rates greater than 200 bpm. Reevaluation over the next 9 months documented resolution of the subaortic stenosis, progressive concentric hypertrophy of both left and right ventricles in the absence of obstruction and progressive, severe systolic and diastolic dysfunction. The pup was always described by her owner as “laid-back” and not very active with a normal gait noted on exam. Bouts of vomiting and inappetance accompanied by severe lethargy and severe metabolic acidosis that persisted (although improved compared to the times of crisis) with resolution of the gastrointestinal signs. Transient improvement in this severe lactic acidosis was noted with bicarbonate infusion. Routine chemistry panels and CBCs were normal. Serum

CK was 134 U/L (Nl 10–200). There has been a clinical response to mitochondrial cofactor treatment. Metabolic testing revealed a plasma lactate of 18.8 mmol/L, pyruvate of 0.28 mmol/L and L/P of 68.4. Lactic aciduria (4374 mmol/mol creatinine, ref 0–200), pyruvic aciduria (2391 mmol/mol creatinine, reference 0–26) and hyperalaninemia (2291 μmol/L, reference 450–672) were found on urine organic acid and plasma amino acid analysis. Analysis of muscle cryosections showed numerous ragged-red fibers, excessive intramyofiber lipid accumulations and PAS positive deposits. Electron microscopy confirmed accumulation of abnormal mitochondria containing large vacuoles and linear crystalline inclusions. Muscle electron transport assays on frozen tissue revealed a very high citrate synthase 1282 nmol/min/mg protein (controls n = 3 mean 326 range 194–410) with CI/CS 33%, CII–III 53%, CIV/CS 28% and CII 40% of the control mean. The muscle histochemistry and EM findings are strongly suggestive of an abnormality in mtDNA and mtDNA analysis is underway. The low complex II activity does however suggest that a nuclear gene defect might be responsible.

doi:10.1016/j.mito.2015.07.110

Abstract 106 Rapamycin as a potential treatment for succinate dehydrogenase mutants in Drosophila melanogaster Presenter: Eugenia Villa-Cuesta Katherine Alvarado, Frances Fan, Eugenia Villa-Cuesta Department of Biology, Adelphi University, PO Box 701, Garden City, NY 11530-0701, USA Abstract: Mitochondria are cellular organelles responsible for the production of almost all energy used by animal cells. Mutations in crucial proteins of the mitochondria cause pathology affecting multiple organ systems; many different disorders can result, ranging from neurodegeneration to cardiomyopathy, and often leading to death. Treatments for mitochondrial disorders are currently based on a combination of vitamins and diet supplements, and are only partially effective. Drosophila melanogaster is an ideal model system for the study of genetic mitochondrial disease since there are multiple mutations in genes that codify for mitochondrial proteins, such as succinate dehydrogenase (SDH). SDH is a tetrameric enzyme involved in both Krebs cycle and electron transport chain. In D. melanogaster mutations affecting SDH contribute to degenerative disorders. Preliminary data in our laboratory showed that the drug rapamycin increases mitochondrial physiology and SDH activity in wild type flies. Here we test the hypothesis that rapamycin protects from SDH deficiency pathology in D. melanogaster. We use three different mutant strains for subunit B of dSDH of D. melanogaster (dSdhB). The climbing abilities, SDH enzymatic activity, ROS production and lifespan under normoxia and hyperoxia are measured to determine the effect of rapamycin on SdhB deficiency. Assessing the role of rapamycin as a potential drug in Drosophila SDH mutants contributes to the current research seeking a treatment for genetic mitochondrial disease in humans.

doi:10.1016/j.mito.2015.07.111

Abstract 107 LARS mutations in non-Irish travelers: An under-recognized multi-system disorder characterized by infantile hepatopathy during physiological stress Presenter: Amy Goldstein