Mitochondrial Diseases

Transcription

1 Mitochondrial Diseases Simon Heales SWIM Conference Taunton, November 29 th 2018

2 Respiratory Failure Cardiomyopathy Optic Atrophy / Retinitis Pigmentosa Seizures / Developmental delay Liver Failure Deafness Short Stature Marrow Failure Peripheral Neuropathy Diabetes Thyroid Disease Myopathy Red Flags

3 1 in 5,000

4 Heteroplasmy & oogenesis Adapted from Taylor, R. W. & Turnbull, D. M. Mitochondrial DNA mutations in human disease. Nat. Rev. Genet. 6, (2005), Nature Publishing Group Gorman, G. S. et al. (2016) Mitochondrial diseases Nat. Rev. Dis. Primers doi: /nrdp

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6 Clinical Picture Genetics Biochemistry Histochemistry Neuroimaging

7 Leigh syndrome Alpers syndrome Phenotypic Syndromes Mitochondrial recessive ataxia syndrome Mitochondrial encephalomyopathy, lactic acidosis & stroke like episodes (MELAS) Myoclonic epilepsy with ragged red fibres (MERFF) Pearson syndrome Kearns-Sayre syndrome (KSS) Progressive external ophthalmoplegia (PEO) Leber hereditary optic neuropathy (LHON) Neuropathy, ataxia and retinitis pigmentosa (NARP) Mitochondrial neurogastrointestinal encephalopathy (MNGIE) Myopathy lactic acidosis and sideroblastic anaemia (MLASA)

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9 Metabolic Biochemistry Lactate normal levels do not exclude. Secondary factors. Plasma amino acids, e.g. alanine Plasma acylcarnitines differential diagnosis. Urine organic acids lactate, TCA cycle intermediates, ethylmalonic acid, 3-methylglutaconic acid, methylmalonic acid (SUCLA2). FGF21 GDF15

10 Diagnostic algorithm for suspected mitochondrial diseases Gorman, G. S. et al. (2016) Mitochondrial diseases Nat. Rev. Dis. Primers doi: /nrdp

11 Muscle Biopsy Skeletal muscle (50-100mg). Flash frozen at bedside. Store at -70 o C. Transported on dry ice. Store at -70 o C. Homogenise (1:9 w/v) Freeze Thaw (x3). Assay.

12 Citrate Synthase a Marker of Mitochondrial Enrichment

13 Mitochondrial Complex Assays NADH Q Succinate Cyt c (Ox) NAD + I QH 2 Fumarate II Q III Cyt c (Red) Rotenone Anitmycin Cyt c (Red) Cyt c (Ox) IV Cyanide O 2 H 2 O

14 Case 7 days; history of poor feeding and lethargy. Elevated serum lactate and hypoglycaemia. 3 weeks; right-sided twitching episodes. EEG revealed asymmetric discharges. MRI normal. TCA cycle intermediates present in urine. 7 weeks: Skin, liver and muscle obtained

15 Muscle Respiratory Chain Enzymes Complex I ( ) Complex II/III ( ) Complex IV ( )

16 Liver Respiratory Chain Enzymes Complex I ( ) Complex II/III ( ) Complex IV ( )

17 Fatty Acid Oxidation Studies Fibroblasts - Sheffield All chain length activities depressed Can support diagnosis of mitochondrial defect

18 Blue Native Gel Electrophoresis Complex V Activity Patient Pooled control V (F 0 + F 1 ) F 1

19 Blue Native Gel Electrophoresis I V III IV II Absent complex III

20 Case Acute regression of motor skills. MRI brain demonstrates bilateral, symmetrical high signal in the basal ganglia and brain stem suggestive of Leigh's syndrome. Also noted to be some thinning of optic chiasm. CSF lactate = 3.2 and serum lactate = 4 and 2.51 on repeat. Current medication: Biotin 30mg bd, Thiamine 100mg tds and Ubiquinone 25mg bd.

21 NDUFV1 mutation.

22 Oxidative Phosphorylation CoQ and Cytochrome c Gorman, G. S. et al. (2016) Mitochondrial diseases Nat. Rev. Dis. Primers doi: /nrdp

23 Neonatal presentation of CoQ 10 Deficiency. J. Pediatr; 139: Presented at 6 hrs with poor feeding, hypothermia and shaking of both arms. Generalised increase in peripheral tone with reduced truncal tone. Initial investigations; lactic acidosis (plasma lactate 19.4 mmol/l). Renal tubulopathy and mild left ventricular hypertrophy with global hypokinesia. Brain MRI demonstrated generalised atrophy and cerebellar atrophy.

24 Muscle Complex II+III Succinate Cyt c (Ox) Fumarate II Q III Cyt c (Red) Anitmycin Complex Activity Ref Range II+III < II III CoQ10 37* ( pmol/mg)

25 Oral CoQ10 therapy 60 to 300 mg/day Decreased plasma lactate 7.6 to 2.5 mmol/l after 4 months Not accompanied by clinical improvement

26 Secondary muscle CoQ10 Deficiency associated with mitochondrial respiratory chain defects. Reported benefits from supplementation.

27 Groups ETC Defects (n=22) Disease Controls (n=26) Cytosolic Cytochrome C ng/mg protein 63.7 ± 15.5* 27.7 ± 2.5

28 SHMT Glycine Serine Diet THF Methionine MAT X Cbl(II) Adomet Methyl transferases B12 Methyl-cbl MS DMG Betaine Gly GNMT Sar Ado.hcy Methyl-cbl Methyl-X Methyl-THF Homocysteine B6 CBS Cystathionine Cysteine

29 5-Methyltetrahydrofolate H 2 N N H N N N O OH CH 3 HN H N OH O O OH CSF deficiency documented in mitochondrial disorders (Allen et al., 1983, Dougados et al., 1983) Responsive to folinic acid No apparent correlation with magnitude of defect

30 CSF 5-MTHF Deficiency & Mitochondrial Respiratory Chain Defects Sex Age (years) 5-MTHF Ref Range (nmol/l) F M M F F Associated in some (25%) but not all patients

31 PLASMA CSF -ve 5MTHF FR1 Endocytosis 1 2 RFC 5MTHF Folate Polyglutamate Pool sfr1 O 2._ 5MTHF???

32 FGF21

33 FGF21 Al Shahrani et al. Unpublished

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35 Relative mtdna content Decanoic Acid & Function Control C10 Treated Control C10

36 ? Biobank Specimen Reception Trials, Research Combined Omics Platforms Personalised Testing Integrated Comprehensive Report

37 Flow Chart Showing Gene-Discovery Approach with the Use of Collaborative Phenomics and Semiautomated Genomics. Tarailo-Graovac M et al. N Engl J Med 2016;374:

38 Acknowledgements Amanda Lam Stuart Bennett Iain Hargreaves Viruna Neergheen Simon Pope Simon Eaton Michael Orford Aziza Khabbush Tom Baldwin Sean Hughes Marta Kanabus Shamima Rahman