Interpret tests for metabolic diseases talk sk yachha

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Interpret tests for metabolic diseases talk sk yachha

  1. 1. Clinical suspicion of metabolic liver disease• Parental consanguinity• Positive family history• Sibling deaths Sudden unexplained / Neuropsychiatric illness/ Seizure disorder/ Myopathies
  2. 2. Inborn errors ± Liver involvement Aminoaciduria 21-70% Incidence in SE Asia Organic acidemia 12-51% 1:2000-9300 live births Fatty Acid Ox Defects 7-27%Condition Incidence/ live births in West Treatable Hereditary Fructose Intolerance 1:20,000 yes Galactosemia 1:40,000-60,000 yes Cong dis of Glycosylation 1b 1:40,000 (Danish) yes Wolman’s ds 1:50,000 no Gauchers 1:100,000 yes Primary hyperoxaluria 1:120,000 yes Niemann-Pick Type C 1:150,000 no Neonatal Hemochromatosis NA yes Bile acid synthetic defects NA yes
  3. 3. Persisting into adulthoodChildren Adults Presenting for the first time Family history Diet history Past history
  4. 4. Hereditary Fructose Intolerance Infant on breast milk
  5. 5. Screening Definitive (available in India) (not available in India) Aldolase B Urine (enzyme assay); Non- glucose reducing Labs. to develop in India, substances + tissue based  Liver <15% of normal, best liver biopsy sample  Small Intestine (in presence of coagulopathy)Liver Bx: “Fructose holes” in EM Gene mutations (20) in 9q
  6. 6. Niemann-Pick Disease Type A Type B Type C (important)(neuronopathic) (non-neuronopathic) Deficiency of enzyme – Cholestrol trafficking Sphingomyelinase effect (Detection in WBC, fibroblasts) Not related to enzyme Neurological Respiratory Liver (45-65%) ± Liver: rare Liver: rare Neurological Neonatal cholestasis (20-30%) with splenohepatomegaly Rarely decompensation and liver failure Older children (50-70%) : Splenohepatomegaly with cirrhosis /portal hypertension Liver adenomas (rarely)
  7. 7. Splenohepatomegaly with liver disease Bone marrow: Foam cells Condition Enzymatic defect Hallmark GM1 gangliosidosis B- galactosidase Dysostosis multiplex, cherry red spotGaucher types I,II, III B- glucoronidaseNiemann Pick A and B Sphingomyelinase Niemann Pick C Cholesterol and Vertical lipid trafficking ophthalmoplegia defect ataxiaWolman ds / Cholestrol Acid estrase Adrenal ester storage ds calcification
  8. 8. Screening Definitive (available in India) (NOT available in India) Bone marrow/Liver Filipin testing histology : foam cells (Accumulation of intracytoplasmic(D/D: Gauchers, Wolman, unesterified cholesterol) GM1 gangliosidosis) To develop in IndiaPlasma chitotriosidase 20-30X elevated than Enzyme analysis normal not to be done (also abnormal (cholesterol trafficking defect) in Gauchers) Available in India Gene mutations (2)
  9. 9. Intracytoplasmic unesterified cholesterol
  10. 10. Wolman’s disease Stormy onsetFirst 2 weeks of life Death 3-6mo
  11. 11. Supportive Definitive Definitive (available in India) (NOT available in India)Hypertriglyceridemia Enzyme assay: GeneHypercholestrolemia Acid Lipase mutations (<10% of normal) 10qFoamy Histiocytes in WBC, skin fibroblasts (LIPA gene) BM/Liver Antenatal Diagnosis (vacuolated chorionic villous sampling hepatocytes) (<12 weeks) Aut. Recessive
  12. 12. Congenital Disorders of Glycosylation CDG 1a CDG 1b (IMPORTANT) Other types Hypoglycemia Neurological Recurrent thrombosis/ No Liver /GI Dysmorphism Coagulopathy manifestations (inverted nipples, (imbalance in pro- and anti-abnormal pads of fat, coagulant factors) Neurological/almond shaped eyes) Protein losing enteropathy Musculo-skeletal and/or Rarely liver Congenital hepatic fibrosis no Rx Transaminitis (moderate) Cirrhosis / Liver FailureDeath by 2 yrs, no Rx Begins in infancyOral Mannose (100-150 mg/kg/dose 5 times a day) ?Cryptogenic May survive into adulthood Liver disease
  13. 13. Congenital Disorders of GlycosylationMannose-6-phosphate isomerase Phosphomannomutase 2 Biosynthesis of the Lipid-Linked Oligosaccharide and Localization of the Early Glycosylation Defects. Square: N-acetylglucosamine; circle: mannose; rhomb: glucose
  14. 14. Specific Definitive Supportive (NOT available in (NOT available in India) India) Quantitative : Serum Enzyme assay:Small bowel histology chromatographic in patients with GI carbohydrate Phosphomannose symptoms: deficient transferrin Isomerase (1b) assayVillous atrophy (x10-20 fold) PhosphomanomutaseLymphangiectasia (Ia) Qualitative: Isoelectric focusing WBC, liver of serum transferrin - cathodal shift Most commonly used Antenatal diagnosis
  15. 15. Non-ketotic hypoglycemia ± High CPK ± Developmental delay FAOD
  16. 16. Fatty Acid Oxidation Defects Screening Definitive (available in India) (NOT available in India) Quantitative Fatty acid analysis Hypoketotic / Non-ketotic C8-10 in MCAD hypoglycemia (in majority) C14-18 in LCHAD C14 in VLCAD GCMS: Urinary organic acid and acylglycine assay (available) Enzyme activity in cultured skinTandem MS: Plasma carnitine and fibroblasts or muscle biopsy acylcarnitine assay (available) Carnitine def. also •Very low levels reaching zero: primary carnitine def •25-50% reduction: Other FAOD
  17. 17. Respiratory Chain Defects Available in India
  18. 18. Definitive Tests Sample Availability in India Ragged red fiber Muscle Yes (Histology) Analysis of oxygen Liver, muscles, fibroblasts No consumption fresh biopsy specimensPolarographic studies required (5-10gm)Enzymatic activity of Frozen samples No respiratory chain (liver, kidney, myocardium) complexes larger tissue (open surgical in most centers)Mt DNA deletions and Muscle No mutations
  19. 19. Organic acidemia Condition Features Specific TreatmentPropionic acidemia None Liver failure Methylmalonenic Pancreatitis Vitamin B12 1mg/day acidemia (MMA) (13mo-9y) NeutropeniaIsovaleric acidemia Glycine 250mg/kg Low Protein diet Carboxylase Reye syndrome, Biotin 20-50mg/day deficiency Skin exfoliationHMG CoA Lyase def Reye syndrome NoneBeta ketothiolase def Fatty liver None
  20. 20. Organic acidemia Condition Urine Ammonia Lactate Glucose ketonesPropionic acidemia Very High normal High/Nl/ Methylmalonenic ++++ (>100µM) Low acidemia (Massive)Isovaleric acidemia Carboxylase ++ High Very High normal deficiency HMG CoA Lyase Absent High/Nl High Low def Beta ketothiolase ++ High/Nl normal Low def
  21. 21. Organic acidemia DiagnosisUrinary organic acid GCMS: ScreeningEnzyme levels fibroblasts: definitive
  22. 22. Courtesy: Dr Moinak Sarma
  23. 23. Urea Cycle Defects Intermittent Child/Adult
  24. 24. Investigations Available in India Amino acid analysis by GCMS Urine Yes Screening PlasmaEnzyme levels (confirmatory)• Carbomyl Phosphatase Fresh liver deficiency Type 1 tissue in• Ornithine transcarbamylase liquid No•N acetyl Glutamate synthetase nitrogen deficiency Comment• Arginino succinic synthetase Difficult• Arginino succinic Lyase Fibroblast deficiency• Arginase RBC
  25. 25. Treatment of urea cycle disorders
  26. 26. Bile Acid Synthetic Defects Supportive Definitive (Not available in India) Plasma bile acid profile (low or absent cholic or chenodeoxycholic acid, Increased intermediary metabolites)Low or normal GGT Fast Atom Bombardment NCS, Rickets, Tandem Mass Spectrometry – no pruritus Urinary bile acid metabolites
  27. 27. Negative for Bile acid disorder
  28. 28. Primary Hyperoxaluria Infancy (20%) Childhood (>50%) Adults (20%) 90% Recurrent Occ. stones Nephrocalcinosis urolithiasis20% Nephrolithiasis Often UTI20% Recurrent UTIESRD 80% at diagnosis Nearly all by 3rd 50% by 3yr decade Recurrence after renal transplant Death by 5yr
  29. 29. Screening Definitive (not available in India) ImagingStones/ nephrocalcinosis Liver biopsy: AGT activity RFT, GFR 50%-70%: undetectable levels 30%-50%: substantial residual 24 hr urine oxalate + compounds: Glycolate Gene mutations L-Glycerate
  30. 30. Normal valuesDisease 24 hr Oxalate excretion 24hr L-Glycerate excretion mmol/1.73m2/d mmol/mmol creatPrimary I >1 6-28Primary II 0.5-1.0 >28
  31. 31. Summary of investigations
  32. 32. Disease Diagnosis Sample India Herediary Aldolase B Liver tissue (best) Not available fructose- intol. (enzyme assay) Small bowel bx. Important , treatable Niemann-Pick Filipin testing Staining of skin Not availableDisease Type C fibroblasts Histopathologist Wolman’s Acid Lipase WBC ( cheaper), Available disease Fibroblasts (Sandor) Antenatal : yes CD Isoelectric serum transferrin Not available Glycosylation focusing -cathodal shift 1b Screening, Important , not specific treatable Enzyme not feasible
  33. 33. Disease Diagnosis Sample India FAOD Screening Blood and urine Sandor, Neogen (TMS/GCMS) Confirmatory Enzymes skin Not available fibroblastsOrganic aciduria Screening Blood and urine Sandor, Neogen (TMS/GCMS) Confirmatory Enzymes skin Not available fibroblasts Urea cycle Screening Blood and urine Sandor, Neogen defects (TMS/GCMS) Enzymes skin Not available Confirmatory fibroblasts LTx… Bile acid Bile acid profile Blood and urine Not availablesynthetic defects and metabolites Develop… treatable
  34. 34. Disease Diagnosis Sample India Primary Screening – 24hr urine Sandor, Neogenhyperoxaluria oxalate & glycolate Confirmatory Liver AGT activity Not available • GAL-1-PUTGalactosemia • Epimerase RBC Available Not widelyTyrosinemia Succinylacetone Urine available Develop… treatable
  35. 35. Sample Collection Storage Blood for TMS 5-7ml heparin tube 4-8°C centrifuge Do not freezeBlood for enzyme 7-8ml 4-8°C assay Do not freeze Urine 10-15ml Freeze 1-2ml for filter paper strip Skin 2x4mm 4-8°C (upper arm) Do not freeze (Do not use betadine) Transport in Gel packed Thermocol box ….Discussion Reach Lab in 2-3 days
  36. 36. Recurrent Recurrent unexplained (high Recurrent hypoglycemia anion gap) acidosis encephalopathy + ketosis No jaundice CNS Liver Heart Hypoglycemia Hyperammonemia Non-ketotic Abnormal urine Very high odour Rest normal hypoglycemia lactateL/P ratio >20 High CPK Organic acidemia Urea cycle defect RCD FAOD

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