Metabolic Disorders Disorders Inborn Errors Of Inborn Errors Of Metabolism Metabolism 1 DR. ABDULLAH ALOMAIR DR. ABDULLAH ALOMAIR MB ChB, MRCP (Edin), FRCP (Edin.), DCH (Glas.) MB ChB, MRCP (Edin), FRCP (Edin.), DCH (Glas.) Associate Professor of Pediatrics Associate Professor of Pediatrics Consultant Pediatrician Consultant Pediatrician Department of Pediatrics Department of Pediatrics PRESIDENT PRESIDENT SAUDI PEDIATRIC ASSOCIATION SAUDI PEDIATRIC ASSOCIATION
Metabolic Disorders Inborn Errors Of Metabolism. DR. ABDULLAH ALOMAIR MB ChB , MRCP ( Edin ), FRCP ( Edin .), DCH ( Glas .) Associate Professor of Pediatrics Consultant Pediatrician Department of Pediatrics PRESIDENT SAUDI PEDIATRIC ASSOCIATION. - PowerPoint PPT Presentation
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Metabolic Disorders Metabolic Disorders
Inborn Errors Of MetabolismInborn Errors Of Metabolism
Associate Professor of PediatricsAssociate Professor of PediatricsConsultant PediatricianConsultant Pediatrician
Department of PediatricsDepartment of Pediatrics
PRESIDENTPRESIDENT SAUDI PEDIATRIC ASSOCIATIONSAUDI PEDIATRIC ASSOCIATION
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Inborn Errors Of Metabolism (IEM)Inborn Errors Of Metabolism (IEM) - - A large group of hereditary biochemical A large group of hereditary biochemical
diseases diseases - Specific gene mutation cause abnormal - Specific gene mutation cause abnormal or missing proteins that lead to altered or missing proteins that lead to altered
function.function.
Metabolic Disorders Metabolic Disorders
Inborn Errors Of MetabolismInborn Errors Of Metabolism
PathophysiologyPathophysiology
SINGLE GENE DEFECTSSINGLE GENE DEFECTS in synthesis in synthesis or catabolism of proteins, or catabolism of proteins, carbohydrates, carbohydrates, or fats. or fats.
DDefect in an efect in an ENZYMEENZYME or or TRANSPORT TRANSPORT PROTEINPROTEIN , which results in a block in a , which results in a block in a metabolic pathway. metabolic pathway.
PathophysiologyPathophysiology
EFFECTS EFFECTS ::
- - toxic toxic ACCUMULATIONACCUMULATION of substrates before the block, of substrates before the block,
- - intermediates fromintermediates from ALTERNATIVEALTERNATIVE pathways pathways
- - defects indefects in ENERGY ENERGY production production and utilization caused band utilization caused by a deficiency of products beyond the BLOCK.y a deficiency of products beyond the BLOCK.
EEvery metabolic disease has very metabolic disease has several several forms that vary in forms that vary in AGEAGE OF OF ONSONSEETT , clinical , clinical severityseverity and, often, and, often, MODE OF INHERITMODE OF INHERITANCEANCE. .
Neonatal and Post Neonatal PresentationNeonatal and Post Neonatal Presentation
Neonatal presentationNeonatal presentationNormal-appearing child at birth (Normal-appearing child at birth (somesome conditions are associated with conditions are associated with dysmorphic features)dysmorphic features)
• poor feedingpoor feeding
• lethargylethargy
• vomitingvomiting
• seizuresseizures
• comacoma
• unusual odourunusual odour
• hypoglycaemia, acidosis (in some hypoglycaemia, acidosis (in some defectsdefects) )
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Neonatal and Post Neonatal PresentationNeonatal and Post Neonatal Presentation
Post neonatal presentationPost neonatal presentation
• Encephalopathy• Developmental regression• Reye syndrome• Motor deficits• Seizures• Intermittent episodes of vomiting, acidosis,
hypoglycaemia and/or coma triggered by
stress e.g. infections, surgery.
Newborn ScreeningNewborn Screening
PKU - in NICU even if not advanced to full feedsPKU - in NICU even if not advanced to full feeds GalactosemiaGalactosemia HypothyroidismHypothyroidism HemoglobinopathiesHemoglobinopathies Biotinidase defic, CAH (21-OH’ase def), Biotinidase defic, CAH (21-OH’ase def), Maple syrup urine disease ( MSUD )Maple syrup urine disease ( MSUD )
- - GUTHRIE TESTGUTHRIE TEST
Specific Tests:Specific Tests:
• Direct biochemical Direct biochemical assays of assays of
metabolites or their metabolites or their metabolic by-metabolic by-
products, or of an products, or of an enzymeenzyme’’s function.s function.
• DNA studiesDNA studies
• Neuro-radiology Neuro-radiology
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PROCEDURES FOR DIAGNOSIC CONFIRMATION
Non – Specific Tests:
• Blood glucose, ammonia, bicarbonate and PH
• Peripheral Blood smear – WBC or bone marrow vacuolization , foam cells or granules.
• C.S.F. glycine , other amino acids , lactate.
Inborn Error of Inborn Error of MetabolismMetabolism
Consideration of Consideration of Prenatal diagnosis Prenatal diagnosis for for pregnancies at risk.pregnancies at risk.
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MANAGEMENT OF IEMMANAGEMENT OF IEM
Family counseling and support.Family counseling and support.
Education to promote increased Education to promote increased compliance with special form of therapy compliance with special form of therapy such as Protein – restricted diet.such as Protein – restricted diet.
Assessment of community resources Assessment of community resources and support groups. and support groups.
● Follows feeding with Follows feeding with lactose containing (breastmilk / formula) lactose containing (breastmilk / formula) ● Patient feeds poorly , have vomiting, jaundice, hepatomegaly Patient feeds poorly , have vomiting, jaundice, hepatomegaly
and hepatic failureand hepatic failure● Chronic liver diseaseChronic liver disease● CataractsCataracts● Developmental delay develop if condition is untreated.Developmental delay develop if condition is untreated.
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CYSTIC FIBROSISCYSTIC FIBROSIS
Cause : Cause : Loss of 3 DNA bases in a gene for the Loss of 3 DNA bases in a gene for the protein that transports Cl ions so salt balance is protein that transports Cl ions so salt balance is upset. Causes a build up of thick mucus in lungs upset. Causes a build up of thick mucus in lungs
Seborric dermatitis or eczema skin.Seborric dermatitis or eczema skin.
Hypertonia.Hypertonia.
Seizures.Seizures.
Severe mental retardation.Severe mental retardation.
Unpleasant odor of phenyl acetic acid.Unpleasant odor of phenyl acetic acid.
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PKU PKU
DIAGNOSISDIAGNOSIS
• Screening : Guthrie Test.
• High Phenylalanine > 20 mg/dl.
• High Phenyl pyruvic acid.
TREATMENTTREATMENT
• DIET.
• BH4 (Tetrahydrobiopterin).
• L – dopa and 5- hydroxytryptophan.
CLINICAL CLINICAL FEATURES FEATURES
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PKU
AlbinismAlbinism
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HomocystinuriaHomocystinuria
Elevated homocystine levels affect collagen , result in a Elevated homocystine levels affect collagen , result in a Marfanoid Marfanoid habitus, habitus, ectopia lentisectopia lentis, mental retardation and strokes, mental retardation and strokes
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METHIONINEMETHIONINE CYSTATHIONINECYSTATHIONINE
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Homocystinuria
Cysathionine
Synthatase
DIAGNOSIS:
High methionine and homocystine.
TREATMENT:
•High dose of B6 and Folic Acid.•Low methionine and high cystine diet,•Betain (trimethylglycine)
HomocystinuriaHomocystinuria
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Amino acid disorders :Amino acid disorders :
Urea cycle defects and hyperammonemiaUrea cycle defects and hyperammonemia
All present with lethargy, seizures, ketoacidosis, neutropenia, and All present with lethargy, seizures, ketoacidosis, neutropenia, and
Remove metabolites via Remove metabolites via dialysisdialysis
Divert Divert metabolitesmetabolites
Supplement with Supplement with cofactor(s)cofactor(s)
An essential nutrient found in highest An essential nutrient found in highest concentration in red meat.concentration in red meat.
Primary function : Primary function : Transport long-chain Transport long-chain fatty acids into mitochondria for oxidation.fatty acids into mitochondria for oxidation.
Carnitine supplementation in Carnitine supplementation in fatty acid fatty acid oxidation disorders and organic acidosis oxidation disorders and organic acidosis may augment excretion of accumulated may augment excretion of accumulated metabolites metabolites , but may not prevent metabolic , but may not prevent metabolic crises in such patients .crises in such patients .
CARNITINE METABOLISMCARNITINE METABOLISM
Important IEM Treatment supplementsImportant IEM Treatment supplements::
Carnitine for elimination of Organic Acid through Carnitine for elimination of Organic Acid through creation of carnitine creation of carnitine esters.esters.
Sodium Benzoate, phenylacetate and Sodium Benzoate, phenylacetate and
phenylbutyrate for Hyperammonemia phenylbutyrate for Hyperammonemia eliminationelimination. .
Therapeutic Measures for IEMTherapeutic Measures for IEM
• D/CD/C oral intake temporarily oral intake temporarily• Usually IVF’s with Usually IVF’s with glucoseglucose to give 12-15 to give 12-15
mg/kg/min glu and at least 60 kcal/kg to mg/kg/min glu and at least 60 kcal/kg to prevent catabolism (may worsen PDH)prevent catabolism (may worsen PDH)
• Bicarb/citrateBicarb/citrate Carnitine/glycineCarnitine/glycine• Na Na Benzoate/arginine/citrullineBenzoate/arginine/citrulline• Dialysis-Dialysis--not exchange transfusion-not exchange transfusion• Vitamins-Vitamins--often given in cocktails after labs -often given in cocktails after labs
drawn before dx is knowndrawn before dx is known• Biotin, B6, B12, riboflavin, thiamine, folateBiotin, B6, B12, riboflavin, thiamine, folate
Type IB G-6-P translocase Same as in von Gierke's disease but may be less severe; neutropenia Pompe
(Type II) Acid maltase Enlarged liver and heart, muscle weakness
Forbe (Cori) (Type III)
Glycogen debrancher Enlarged liver or cirrhosis; low blood sugar levels; muscle damage and heart damage in some people
Andersen (Type IV)
Glycogen branching enzyme Cirrhosis in juvenile type; muscle damage and CHF
McArdle's (Type V)
Muscle glycogen phosphorylase
Muscle cramps or weakness during physical activity
Her (Type VI)
Liver glycogen phosphorlyase Enlarged liver; often no symptoms
Tarui (Type VII)
Muscle phosphofructokinase Muscle cramps during physical activity; hemolysis
Type VIII Unknown Hepatomegaly; ataxia, nystagmus Type IX Liver phosphorylase kinase Hepatomegaly; Often no symptoms Type X Cyclic 3-5 dependent kinase Hepatomegaly, muscle pain (1 patient) Type XI Unknown Hepatomegaly. Stunted growth, acidosis, Rickets
PPrinciple Groups of rinciple Groups of Glycogen Storage DiseasesGlycogen Storage Diseases
Clinical And Pathological Clinical And Pathological Ultra structure Of Ultra structure Of
MucopolysaccharidosesMucopolysaccharidosesDiseaseDisease Clinical ManifestationClinical Manifestation Ultrastructure of Stored Ultrastructure of Stored
MaterialMaterial
MPS type IMPS type I
HurlerHurler
Earliest, most severe Earliest, most severe developmental regressiondevelopmental regression
coarse facial featurescoarse facial features
HepatosplenomegalyHepatosplenomegaly
dystosis of bonedystosis of bone
cardiac involvementcardiac involvement
corneal cloudingcorneal clouding
Fibrillogranular Fibrillogranular mucopolysaccharides in cells of mucopolysaccharides in cells of viscera and brainviscera and brain
MPS type IIMPS type II
HunterHunterX-linkedX-linked
Later developmental regressionLater developmental regression
coarse facial featurescoarse facial features
hepatosplenomegaly hepatosplenomegaly
dystosis of bone cardiac dystosis of bone cardiac involvementinvolvement
minimal corneal cloudingminimal corneal clouding
Fibrillogranular Fibrillogranular mucopolysaccharides in cells of mucopolysaccharides in cells of viscera and brainviscera and brain
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63Hurler’s
64Hurler’s
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66 Mcopolysacch. Morquio
Due to dysfunction of a Due to dysfunction of a single or multiple single or multiple peroxisomal enzymesperoxisomal enzymes, or to failure to form or , or to failure to form or maintain a normal number of functional maintain a normal number of functional peroxisomes.peroxisomes.
PeroxisomesPeroxisomes = Subcellular = Subcellular organelles organelles involved involved in various essential in various essential anabolic or catabolic anabolic or catabolic processes, biosynthesis of Plasmalogens and bile processes, biosynthesis of Plasmalogens and bile acids. acids.
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PEROXISOMAL DISORDERSPEROXISOMAL DISORDERS
Hypotonia.Hypotonia.
Dysmorphia.Dysmorphia.
Psychomotor delay and seizures.Psychomotor delay and seizures.
Hepatomegaly.Hepatomegaly.
Abnormal eye findings such as retinitis pigmentosa Abnormal eye findings such as retinitis pigmentosa or cataract.or cataract.
Progressive degeneration of Brain/Liver/Kidney, with death ~6 mo after onset.
When screening for PDs. obtain serum Very Long Chain Fatty Acids- VLCFAs
70Zellweger
71Chond punct
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THANK YOU
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Metabolic Metabolic DisordersDisorders
Due to inherited reduced activities of proteins Due to inherited reduced activities of proteins involved in the synthesis, breakdown or transport of involved in the synthesis, breakdown or transport of amino acids, organic acids, fats, carbohydrates and amino acids, organic acids, fats, carbohydrates and complex macromolecules. complex macromolecules.
Most are autosomal recessive due to mutations that Most are autosomal recessive due to mutations that result in reduced enzyme activity or reduced amount result in reduced enzyme activity or reduced amount of enzyme.of enzyme.
Pathogenesis may include: accumulation of a toxic Pathogenesis may include: accumulation of a toxic intermediate, reduced amount of a necessary end intermediate, reduced amount of a necessary end product or activation of an alternate pathwayproduct or activation of an alternate pathway..
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Inborn Errors of Metabolism of Acute Onset: Nonacidotic, Nonhyperammonemic Features Neurologic Features Predominant (Seizures, Hypotonia, Optic Abnormality) Glycine encephalopathy (nonketotic hyperglycinemia) Pyridoxine-responsive seizures Sulfite oxidase/santhine oxidase deficiency
Clinical Symptomatology of Inborn Errors of Metabolism (IEM) in the Neonate or Infant Symptoms indicating possibility of an IEM (one or all)
Infant becomes acutely ill after period of normal behavior and feeding; this may occur within hours or weeks
Neonate or infant with seizures and/or hypotonia, especially if seizures are intractable
Neonate or infant with an unusual odor Symptoms indicating strong possibility of an IEM, particularly when coupled
with the above symptoms Persistent or recurrent vomiting Failure to thrive (failure to gain weight or weight loss)
Apnea or respiratory distress (tachypnea) Jaundice or hepatomegaly Lethargy Coma (particularly intermittent) Unexplained hemorrhage Family history of neonatal deaths, or of similar illness, especially in
GROUP I : GROUP I : BIOGENSISBIOGENSIS OF PEROXISOME OF PEROXISOME
GROUP III GROUP III :: POSITIVE PEROXISOMES BUT POSITIVE PEROXISOMES BUT MULTIPLEMULTIPLE DEFECTIVE DEFECTIVE ENZYME ENZYMEZellweger syndrome
(cerebrohepatorenal syndrome).
Neonatal adrenoleukodystrophy.
Infantile Refsum disease.
Hyperpipecolic acidemia.
Refsum disease.
X - linked Adreno-Leuko-Dystrophy.
Pseudo – Zellweger syndrome.
Hyperoxaluria….etc.
Zellweger – Like.
Pseudo – infantile Refsum disease.
Rhizomelic chondro-dysplasia
punctata
Mitochondrial Syndromes Mitochondrial Syndromes Presenting in Childhood to Presenting in Childhood to
AdultAdultSyndromeSyndrome Most Common Most Common
Clinical Clinical PresentationPresentation
Other Cliical Other Cliical FeaturesFeatures
Mt DNA Mt DNA DefectDefect
MELAS: myopathy, MELAS: myopathy, encephalopathy, encephalopathy, lactic acidosis and lactic acidosis and stroke-like episodesstroke-like episodes
Stroke-like episodes Stroke-like episodes in the first and in the first and second decade of second decade of life often associated life often associated with migraine with migraine headache, blood headache, blood lactate lactate
Clinical Presentation of Amino Acid DisordersClinical Presentation of Amino Acid Disorders
Mitochondrial Mitochondrial DisordersDisorders
Classically involve mutations in Classically involve mutations in mitochondrial DNAmitochondrial DNA
Follow a Follow a maternalmaternal pattern of inheritance pattern of inheritance
Highly variable with regard to penetrance and Highly variable with regard to penetrance and expressivity based on the variability in tissue expressivity based on the variability in tissue distribution of abnormal mitochondriadistribution of abnormal mitochondria
OtherOther Most Common DiagnosisMost Common Diagnosis
KetoAcidosisKetoAcidosis
LethargyLethargy
OdorOdor
Ammonia: Normal or slightly Ammonia: Normal or slightly elevated Ketones: Elevated elevated Ketones: Elevated Glucose: Normal Glucose: Normal
Maple syrup urine diseaseMaple syrup urine disease
AcidosisAcidosis
LethargyLethargy
OdorOdor
Ammonia: Elevated Ammonia: Elevated Glucose: Normal or Glucose: Normal or decreased Ketones: decreased Ketones: May be elevated May be elevated Lactate: Slightly elevatedLactate: Slightly elevated
Acidosis: Usually present Acidosis: Usually present Ammonia: Normal or slightly Ammonia: Normal or slightly elevated elevated Ketones: May be elevated Ketones: May be elevated
Recurrent emesis with coma and hepatic dysfunction.Recurrent emesis with coma and hepatic dysfunction.
Hypertonia / hypotonia.
Failure to thrive.
Ophthalmic – related problems : e.g. cataract, corneal
cloudiness, cherry red spot, optic atrophy.
Renal failure or renal tubular acidosis.
CARNITINE METABOLISMCARNITINE METABOLISM
An essential nutrient found in highest concentration in red An essential nutrient found in highest concentration in red meat.meat.
Primary function : Primary function : Transport long-chain fatty acids into Transport long-chain fatty acids into mitochondria for oxidation.mitochondria for oxidation.
Primary defects of carnitine transport manifest as Reye Primary defects of carnitine transport manifest as Reye syndrome , cardiomyopathy or skeletal myopathy with syndrome , cardiomyopathy or skeletal myopathy with hypotonia hypotonia
Secondary carnitine deficiency is due to diet Secondary carnitine deficiency is due to diet ( esp. I.V alimentation or ketogenic diet ) , renal losses , ( esp. I.V alimentation or ketogenic diet ) , renal losses , drug therapy ( esp. valproic acid) and other metabolic drug therapy ( esp. valproic acid) and other metabolic disorders ( esp. disorders of fatty acid oxidation and disorders ( esp. disorders of fatty acid oxidation and organic acidemias )organic acidemias )
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CARNITINE METABOLISMCARNITINE METABOLISM
Prognosis depends on the cause of the carnitine Prognosis depends on the cause of the carnitine abnormality.abnormality.
Free and esterified carnitine can be measured in Free and esterified carnitine can be measured in blood.blood.
Oral or I.V. L-carnitine is used in carnitine Oral or I.V. L-carnitine is used in carnitine deficiency or lnsufficiency in doses of deficiency or lnsufficiency in doses of 25-100mg/kgm/day or higher.25-100mg/kgm/day or higher.
Carnitine supplementation in Carnitine supplementation in fatty acid oxidation fatty acid oxidation disorders and organic acidosis may augment disorders and organic acidosis may augment excretion of accumulated metabolites excretion of accumulated metabolites , but may not , but may not prevent metabolic crises in such patients .prevent metabolic crises in such patients .
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Management of IEM - NICUManagement of IEM - NICU
• Stop nutrient Stop nutrient triggering triggering disorder e.g. protein, galactosedisorder e.g. protein, galactose• Give high-Give high-energyenergy intake intake• NICU care NICU care to correct tissue perfusion, dehydration, to correct tissue perfusion, dehydration,
acidosisacidosis• Hyperammonemia Rx with Na Hyperammonemia Rx with Na benzoatebenzoate, Na , Na
phenylbutyrate, argininephenylbutyrate, arginine• DialysisDialysis• Insulin Insulin to control hyperglycemia and reduce catabolismto control hyperglycemia and reduce catabolism• Vitamins e.g Biotin, B6, B12Vitamins e.g Biotin, B6, B12• Specific therapy e.g. Specific therapy e.g. carnitine, glycinecarnitine, glycine
SINGLE GENE DEFECTS in synthesis or catabolism of proteins, carbohydrates, or fats.
Defect in an ENZYME or TRANSPORT PROTEIN , which results in a block in a metabolic pathway.
EFFECTS :
- toxic ACCUMULATION of substrates before the block,
- intermediates from ALTERNATIVE pathways
- defects in ENERGY production and utilization caused by a deficiency of products beyond the BLOCK.
Every metabolic disease has several forms that vary in AGE OF ONSET , clinical severity and, often, MODE OF INHERITANCE.
Pathophysiology
Dependent on diagnosis and Dependent on diagnosis and
severity:severity:
Dietary or vitamin therapyDietary or vitamin therapy
Drug therapyDrug therapy
BMTBMT
Avoid known environmental triggersAvoid known environmental triggers
SurgerySurgery
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MEDICALMEDICAL
Transient Hyperammonemia of Transient Hyperammonemia of Newborn Newborn::
Markedly highMarkedly high NH4 NH4 in an infant less than 24 HOL, or first in an infant less than 24 HOL, or first 1-2 DOL before protein intake occurs.1-2 DOL before protein intake occurs.
Often in context of large, Often in context of large, prematurepremature infant with infant with symptomatic pulmonary disease.symptomatic pulmonary disease.
Very Very sick sick infant. infant.
Unknown precipitant, Unknown precipitant, unknownunknown etiology (possible slow etiology (possible slow delayed urea cycle initiation), with potential for severe delayed urea cycle initiation), with potential for severe sequelae (20-30% death, 30-40% abnl dev.) if not treated. sequelae (20-30% death, 30-40% abnl dev.) if not treated.
Does not recurDoes not recur after being treated. after being treated.