Metabolic Disorders Flashcards

(48 cards)

1
Q

PKU

A
  • MOST COMMON amino aciopathy (1/10,000-15,000)
  • AR mutations in PAH
  • untreated: ID, seizures, musty odor, psych
  • inc. phenylalanine, dec. tyrosine
  • treated: generally unaffected
  • dietary protein restriction
  • Kuvan works for some
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2
Q

Tyrosinemia type I

A
  • amino aciopathy
  • AR mutations in FAH
  • more common in Quebec (1/16,000)
  • untreated: liver failure in infancy, kidney dysfxn, growth failure, rickets, neuro crises, death <10y, rotton eggs odor
  • increased phenylalanine and tyrosine in plasma, increased succinylacetone in urine
    treated: inc. risk hepatocellular carcinoma, corneal cysts, normal growth, increased liver fxn
  • drug treatment NTBC, dietary protein restriction, manage liver disease
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3
Q

Homocytinuria

A
  • amino aciopathy
  • AR mutations in CBS
  • more common in Qatar (1/1,800)
  • untreated: ID, marfanoid, ectopia lentis (down), thromboembolism, neuro sequelae
  • increased homocystine and methionine
  • treated: inc. risk for thromboembolism, risk of ectopia lentic, normal growth and intelligence
  • supplement with B6, folate, B12, dietary protein restriction, avoid OCPs
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4
Q

MSUD

A
  • amino aciopathy
  • AR mutations in BCKDHA (45%), BCKDHB (35%), DBT (20%)
  • more common in Mennonites
  • newborn metabolic crisis: irritability, feeding and resp issues, opisthotonas
  • reduced IQ, movement disorders, risk of depression, ADHD, and anxiety
  • increased BCAAs (leucine, isoleucine, valine)
  • dietary protein restriction (most aggressive when sick)
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5
Q

Amino acidopathies presentation

A
  • chronic and progressive
  • usually no neonatal crisis (except MSUD)
  • all AR
  • symptoms develop slowly
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6
Q

Urea cycle defects

A
Neonatal presentation:
- increased ammonia, encephalopathy, resp. alkalosis:
- seizure, coma, death
- resembles sepsis but normal glucose
- onset 24-72hrs of life
Childhood and adult presentation
-  infections, neuro involvement, psych issues
- PREVENT CATABOLISM
- SUPPLEMENT WITH ARGININE (unless ARG)
LIVER TRANSPLANT = CURE
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7
Q

CPS deficiency

A
  • urea cycle defect
  • AR mutations in CPS1
  • plasma AAs: low citrulline and arginine
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8
Q

OTC deficiency

A
  • MOST COMMON urea cycle defect
  • XL mutations in OTC
  • plasma AAs: low citrulline and arginine
  • high urinary orotic acid
  • 10-15% CARRIER females symptomatic
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9
Q

ASS deficiency/Citrullinemia

A
  • urea cycle defect
  • AR mutations in ASS1
  • super inc. citrulline, dec. arginine
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10
Q

ASL deficiency

A
  • urea cycle defect
  • AR mutations in ASL
  • inc. citrulline and arginosuccinate, dec. arginine
  • variable
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11
Q

ARG deficiency

A
  • urea cycle defect
  • AR mutations in ARG1
  • onset 1-3y: progressive spasticity, psychomotor retardation, feeding issues, DD, seizures
  • increased arginine
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12
Q

Organic Acidurias

A
  • high risk of decompensation prior to NBS results
  • prevent catabolism!
  • acute presentation: toxic encephalopathy, dec. feeding, poor tone, seizures, irritability, lethargy -> coma
  • all AR
  • treat with carnitine supplementation
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13
Q

Propionic acidemia

A
  • organic aciduria
  • AR mutations in PCCA, PCCB
  • cannot metabolize: isoleucine, valine, threonine, methionine
  • neonatal fast breathing
  • cardiomyopathy
  • pancreatitis
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14
Q

Glutaric Acidemia

A
  • MOST COMMON organic aciduria (1/30-40,000)
  • AR: GCDH
  • up to 1/300 Amish
  • metabolic crisis after 2 months
  • severe movement disorder: spasticity/dystonia (from glutaric acidemia)
  • macrocephaly
  • treat: low lysine diet
  • 30-40% have neuro impariment w/ treatment
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15
Q

Methlymalonic aciduria

A
  • organic aciduria
  • AR: MUT (genotype/phenotype…22% have limited activity)
  • looks like PA in severe genotype
  • very high MMA
  • treatment: DPR, B12 injections, prophylactic antiboitics
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16
Q

Isovaleric Aciduria

A
  • organic aciduria
  • AR: IVD
  • similar to PA and MMA neonatal crisis, BUT fewer longterm complications
  • “sweaty feet odor”
  • treatment: low leucine
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17
Q

Metabolic conditions w/ psychiatric findings

A

PKU, Galactosima, MCADD, ASA, Citrullinemia (ASD), homocystinuria

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18
Q

Fatty Acid Oxidation Disorders

A
  • causes sudden infant death
  • avoid fasting!
  • low fat diet w/ fatty acid supplementation
  • cornstarch
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19
Q

SCAD

A
  • not a disorder…in vast majority

-

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20
Q

MCADD

A
  • most common fatty acid oxidation disorder
  • AR: ACADM
  • NBS: ^C6-C10
  • presentation 3-24 months (when feeds decrease at night)
  • vomiting, seizure etc etc
  • hypoketotic hypoglycemia
  • no impact on congnition if caught early
  • acute liver disease
21
Q

LCHAD

A
  • FAOD
  • AR: HADHA
  • NBS: ^C14-C18
  • female carriers at risk for HELLP during pregnancy (treatment=delivery)
  • cardiomyopathy, liver disease, hypotonia, neuropathy, retinopathy
22
Q

VLCAD

A
  • FAOD
  • AR: ACADVL
  • NBS: ^C14
  • cardiac issues, hypotonia, hepatomegaly, intermittent hypoglycemia
23
Q

CPTII

A
  • FAOD
  • AR: CPT2
  • lethal neonatal form: liver failure, CM, death in days/mos
  • Severe infantile form: liver failure, CM, onset in 1st year, sudden death common
  • Myopathic form: most common, variable AOO, myalgia attacks only
24
Q

Sphingolipidoses

A
  • 3 classes 1) cerebrosides 2) sphingomyelins 3) gangliosides
  • Niemann-Pick
  • Gaucher
  • Fabry
  • Tay Sachs (GM2)
  • Krabbe
  • Metachromatic Leukodystrophy
25
Niemann-Pick
- LSD/sphingolipidosis - AR: SMPD1 - Type A: neuropathic, HSM, FTT, regression at 1yr, 100% have cherry red spot, respritory failure, early childhood death - Type B: non-neuropathic, similar but later onset, 1/3 neuro impairment and cherry red spot, delayed bone age, short stature
26
Gaucher
- MOST COMMON LSD/sphingolipidosis - AR: GBA - Type 1: least severe and most common, ERT (cannot cross BBB), excellent prognosis - Type 2: most severe, 2-4 yr lifespan - Type 3: intermediate, chronic neuro disease - Features: bone disease, HSM, anemia, thrombocytopenia, lung disease, decreased platelets
27
Fabry
- LSD/sphingolipidosis - XL: GLA - childhood/adolescent onset - Features: stroke, renal failure, CM, corneal opacities, GI issues, hypohydrosis/anhhydrosis - Males=enzyme testing, females=molecular testing - a lot of depression and anxiety in Fabry families - untreated= ESRD/CVD by 3rd to 5th decade - ERT= lowers substrate, but not proven to extend life
28
GM2/ Tay Sachs
- LSD/sphingolipidosis (gangliosidosis) - AR: HEXA - b-hexosaminidase A - onset 6 months: exaggerated startle response, loss of milestones, macular cherry red spot, spacticity, trouble swallowing, seizures, - death from asphyxiation 2-4yrs. - palliative - adult onset=ataxia + psychosis
29
Krabbe
- LSD/sphingolipidosis - AR: GALC b-galactocerebrocidase - usually 30 kb deletion - leukodystrophy, demylenating CNS+PNS - progressive: DD, regression, irritability, hypertonia, peripheral neuropathy, white matter disease, ^CSF protein concentration
30
Mucopolysacharidoses
- lack of lysosomal enzymes that break down glycosaminoglycans (aka mucopolysaccharides) - bone marrow
31
Hurler
- MPS I - AR: IUDA - severe ID/DD, corneal clouding, coarse facies, umbilical hernia at birth, hydrocephalus, hepatosplenomegaly, dysostosis multiplex, heart valve abnormalities, hearing loss, gibbus deformity, chronic resp. infections - ERT available, death in 8-10y without
32
Hunter
- MPS II - XLR: IDS - onset 2-4y - NO CORNEAL CLOUDING, HSM, communicating hydrocephalus, camptodactyly, joint contractures, "pebbly" skin, recurrent ear infections, hirsuitism, gait abnormality, cardiac problems, respiratory infections
33
Scheie
- MPS I-S - AR: IUDA - onset after age 5 - no psychomotor impairment, normal height, normal lifespan, normal intelligence - retinal degeneration, severe progressive skeletal disease, deafness, carpel tunnel syndrome - ERT available, more successful when no neuro involvement
34
Sanfilippo
- MPS III (MOST COMMON MPS) - AR: 4 genes (clinically same) - CNS degeneration 2-6y, profound ID by 6-10y, severe sleep disturbances, NO corneal clouding, typically normal stature, seizures (late stage) - no therapy, death in adolescence - early 20s
35
Morquio
- MPS IV - AR: 2 genes (clinically same) - severe skeletal involvement: shortening of trunk, kyphosis, C spine instability (spinal cord compression), pectus carinatum, dental abnormalities - normal intelligence - mitral valve insufficiency - mild corneal clouding and HSM - ERT for type A, survival to adulthood
36
Maroteaux-Lamy
- MPS VI - onset of growth retardation at 2-3y - resembles Hurler, but normal intelligence - shortened lifespan - cardiovascular disease - progressive pulm HTN - ERT available
37
Sly
- MPS VII - AR - slydrops fetalis in severe form - Hurler-like in moderate form: HSM, ID, dysostosis multiplex, coarse facies, short stature - No ERT, death in teens
38
Alpha-mannosidosis
- oligosaccharidosis - AR: MAN2B1 - clinically resembles an MPS but MPSs in urine are normal because enzymes never make it to lysosomes
39
Glycogen storage disorders
- increased glycogen in tissues - LIVER: Von Gierke (GSD I), Cori (GSD III), Anderson (GSD IV) - LIVER & MUSCLE: Phosphorylase kinase deficiency (GSD IX) - MUSCLE: Pompe (IIa), McArdle (V)
40
Von Gierke
- GSD I - MOST COMMON GSD - AR: G6PC, SLC37A4 - primarily affects liver - hepatomegaly, kidney failure, thrombocyte dsfxn - avoid fasting, supplement w/ cornstarch
41
Pompe
- GSD IIa - AR: GAA - more common in AA - primarily affects heart and muscle (myopathy and CM) - infantile form = death by 2 - juvenile form = myopathy - adult form = similar to MD - ERT available
42
McArdle
- GSD V - MOST COMMON MUSCLE GSD - AR: PYGM - affects muscles: exercise intol., inc. CK - "warm up phenomenon"
43
Galactosemia
- AR: GALT - brain damage, cataracts, jaundice, hepatomegaly, sepsis - treat: lactose and galactose restriction - diet independent long term complications: DD, ataxia, anxiety, depression, POF
44
Hereditary fructose intolerance
- AR: ALDOB - appears when fruits/juice enter diet - lethargy, jaundice, seizure, coma - treat: no fructose, sorbitol, sucrose
45
Lesch-Nyhan
- XL: HRPT1 - hyperuricemia --> gout, urea crystals - dystonia, chorea, self-injury - disorder of purine metabolism
46
Batten disease
- AR: CLN# - epilepsy, movement disorder, cognitive decline - terminal - regression
47
Metabolic Psych Stuff
- PKU: learning difficulties - Galactosemia: social anxiety - MCAD: withdrawn, lang. delays - Citrullinemia: delayed motor skills
48
ERT available
- MPS I (Hurler) - MPS II (Hunter) - MPS IVA (Morquio A) - MPS VI (Maroteaux-Lamy) - Gaucher - Fabry