inborn errors of metabolism Flashcards

1
Q

deficiency in pku

A

phenylalanine transferase (cant convert phe to tyrosine); mild problem with BH4

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2
Q

lab results for pku

A

UOA: inc phenylketones
PAA: inc Phe, low tyrosine

due to low tyrosine-
1. low neurotransmitters: dopamine, norepinephrine, and adrenaline
2. fair skin (Tyr is a precursor of the skin pigment melanin)

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3
Q

PKU as teratogen (features)

A

dysmorphic features, microcephaly, IUGR, congenital heart

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4
Q

clinical features in infant with PKU

A

fair skin

eczematoid rash

mousy/musty odor

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5
Q

treatment of PKU

A

restrict phe, BH4 supplement

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6
Q

first test for change in mental status

A

blood glucose

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7
Q

condition could falsely elevate NH4

A

use torniquet, prolonged process in lab (result in 1 hr), no ice

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8
Q

how to collect NH4

A

free flow, ice, process within 1 hr

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9
Q

Condition with elevated lactate:pyruvate

A

mitochondrial d/o

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10
Q

What presents with elevated plasma AA

A

aminoacidopathies, urea cycle, organic acedemia

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11
Q

What presents with abnormal urine organic acid

A

AA, FAOD, organic acid

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12
Q

Mode of inheritance of aminoacidopathies

A

autosomal recessive

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13
Q

Labs suggestive urea cycle do

A

AbN PAA, elevated NH4, respiratory alkalosis

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14
Q

Labs suggestive Organic Acids

A

Abn PAA, metabolic acidosis, AbN UOAs

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15
Q

Deficiency in MSUD

A

branched chain alpha ketoacid dehydrogenase

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16
Q

What are the Branched-chain AA

A

Isoleucine, valine, LEUCINE

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17
Q

MSUD and ethnic group

A

Old order Mennonites

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18
Q

presentation MSUD

A

diminished arousal

poor feeding

hypertonia

coma

death

maple syrup smell

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19
Q

which branched-chain AA causes Sx in MSUD

A

Leucine (neurotoxic and osmotic effect)

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20
Q

Acute mgt of MSUD

A

high dextrose isotonic Iv and lipids; serum Na high normal

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21
Q

long term mgt for MSUD

A

diet, liver transplant

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22
Q

deficiency in homocystinuria

A

deficiency in cystathionine beta synthetase

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23
Q

labs finding homocystinuria

A

elevated homocysteine and methionine in blood, urine, NBS, plasma AA

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24
Q

clincal features of homocystinuria

A

intellectual disability

tall stature

osteoporosis

recurrent thrombosis

ectopia lentis (lens dislocation- downwards)

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25
differential for homocystinuria
marfans
26
Management of homocystinuria
vit B6 (cofactor) betaine (dec homocysteine in bld) aspirin (prevent stroke)
27
deficiency in tyrosinemia (hepatorenal tyrosinemia)
fumarylacetoacetase
28
pathognomonic tyrosinemia
inc tyrosine (lacks specificity and sensitivity) must differentiate from transient tyrosinemia of newborn inc urine and bld succinyl acetone
29
Confirmation tyrosinemia
UOA: succinylacetone PAA inc tyrosine and methionine (liver issue)
30
Treatment tyrosinemia
Nitisinone, tyrosine restrict
31
Deficiency Hyperglycinemia (nonketotic hyper**glycine**mia)
deficiency in glycine cleavage
32
lab and clinical findings in hyperglycinemia
inc CSF glycine seizure hiccups apnea Absent corpus collosum EEG burst supression
33
urea cycle
A- N-acetylglutamate synthetase B- Carbamyl phosphate synthetase C- Ornithine carbamyl transferase D- Arginosuccinic acid synthetase E- Argininosiccinic lyase F- Arginase
34
findings in urea cycle oct def
high: glutamine, orotic acid low: citrulline, arginine
35
urea cycle def arginosuccinic acid synthetase
high: glutamine, orotic acid, citrulline low: arginine
36
urea cycle arginase def
cant change arginine last step- all high: glutamine, orotic acid, citrulline, arginine
37
Which inborn metab defect is X-linked recessive
OCT (ornithine carbamyl transferase)
38
Treatment to remove ammonia
1. hemodialysis (fastest) 2. Hydration 3. Remove nitrogen: sodium benzoate and sodium phenylacetate- scavenger, water soluble 4. Sodium phenylbutyrate- once stable
39
What to monitor when treating with Benzoate for NH4
Na and Cl (high Na content, hence improtance of hydration)
40
What affects outcome for urea cycle DO
length of time with high NH4
41
Outcome/Risk for arginase deficiency
Spastic diplegia
42
What is organic acids
deaminated remains of amino acids
43
What is lab finding for organic acidemia
1. metabolic acidosis with elevated anion gap 2. NBS: odd chain acylcarnitine (C3, C5)
44
Treatment of acute episode organic acidemia (6)
1. high dose carnitine 2. IVF D10 with NS 3. IV lipid 4. Insulin (anabolic) 5. Biotin and Vit B12 (cofactor) 6. Glycine (binds to nontoxic form)
45
lab findings pathognomic of urea cycle DO
Elevated ammnonia Respiratory alkalosis No ketoacidosis
46
What is the major metabolite of AA and lipid
Propionyl-CoA
47
Defect in glutaric acid acidemia
defect in glutaryl CoA dehydrogenase (metabolism of tryptophan and lysine)
48
Ethnic group associated with glutaric acidemia
Amish
49
Which organic acidemia does not present with metabolic acidosis, ketosis and hyperammoniemia
Glutaric acidemia
50
Long term morbidity in glutaric acidemia
Involuntary movements (due to basal ganglia injury)
51
What organic acidemia is child abuse a differential?
Glutaric acidemia (risk for subdural hemorrhage and retinal hemorrhage)
52
What triggers the sequela of glutaric acidemia
**Fever** (resulting in dystonia and movement disorder)
53
Associated with sweaty feet
Isovaleric aciduria
54
Associate with male cat urine
3 methylcrotonyl glycinuria
55
Key feature of FAOD (fatty acid oxidation do)
hypoketotic hypoglycemia with prolonged fasting
56
Long Term complication of LCHAD and VLCAD
1. rhabdomyolysis 2. cardiomyopathy 3. liver dysfunction 4. retinopathy 5. peripheral neuropathy
57
Complication of heterozygous LCHAD preg women
1. fatty liver 2. HELLP 3. if with this- 1:5 chance of delivering baby with LCHAD
58
Management with LCHAD
1. frequent feed 2. mct formula 3. Avoid breastfeeding initially
59
What AA is carnitine made by human de novo from?
Lysine and methionine
60
What causes carnitine deficiency
1. failure to synthasize (Glutaric acidemia) 2. Defective carnitine transport (defect in OCTN2 carnitine transporter- dec intestinal absorption and renal reabsroption) 3. Depletion of carnityl esters (FAO) 4. preterm infants
61
Function of carnitine
1. Transport long chain FA into the mitochondria to produce energy 2. Metabolic scavenger
62
presentation of galactosemia
1. poor feeding 2. vomiting 2-3 DOL 3. Jaundice- hepatomegaly, liver failure 4. RTA (acidosis, glycosuria, aminoaciduira) 5. Cataract (from excess galactitol)
63
Sepsis from E coli think of...
galactosemia
64
Long term risk with galactosemia even wth proper treatment
1. premature ovarian failure 2. tremors 3. learning disability
65
lab test for galactosemia
1. LFT 2. low glucose 3. Inc galactose in urine (use clinitest- use to identify reducing substance)
66
Management for galactosemia
1. initiate tx immediately with positive NBS result 2. No BM (avoid lactose and galactose)- switch to soy or elemental formula 3. estrogen replacement for female 4. screen for learning disability
67
What are the 2 glycogen storage do can present in neonates
1. von Gierke disease (type I) 2. Pompe (type II)
68
GSD that affects the liver with direct influence with blood glucose and present with lactic acidosis
Von Gierke Enzyme: glucose 6 phosphatase
69
Which GSD affects various tissue but no direct effect on blood glucose
Pompe (Type II) Enzyme lysosomal alpha glucosidase
70
which GSD can have cardiomyopathy
Pompe disease
71
Which GSD can have hepatic tumor
Von Gierke
72
Presents with introduction of formula, fruit or vegtables
fructosemia - contains sucrose (formula), fructose or sorbitol
73
Which organelle digests complex molecules for recycling or degradation
lysosome
74
Pathognomonic for mucopolysaccharidoses
Dystosis multiplex (defects of bones and joints) Alder-Reilly bodies in WBC Urine with mucopolysacharrides
75
pathognomonic for lipid storage disease affecting the brain
Macular cherry red spot (Gaucher does not have macular cherry- does not affect CNS)
76
difference between lipidoses presenting in infancy
77
symptoms of Tay-Sachs
from accumulation of sphingolipid GM2 1. weakness 2. exagerated startle 3. myoclonic jerks 4. mental regression (unresponsive to environment) 5. cheery red spot 6. progressive macroecphaly
78
symptom of Gaucher dis Type I **(Ga-OUCH)**
from accumulation of glucocebroside in liver, spleen and bone marrow 1. anemia/thrombocytopenia 2. HSM 3. bone pain
79
Most common lysosomal storage disease
Gaucher Disease type 1 -non CNS disease with splenomegaly Ethnicity: Ashkenazi Jews
80
What is the late complication of propionic acidemia
Cardiomyopathy
81
What are the findings in propionic acidemia
Severe ketoacidosis w or w/o hyperammonemia Encephalopathy, vomiting, bone marrow suppression
82
Infant presents normal at birth but few weeks later presents with: hypotonia, muscle weakness Macroglossia Hepatomegaly CHF due to hypertrophic cardiomyopathy Elevated CPK, AST, LDH Muscle biopsy: vacuoles full of glycogen on staining
Pompe disease -defect in lysosomal acid alpha 1,4 glucosidase (acid maltase)
83
What defect has cataract as the only finding (completely asymptomatic)
Galactokinase deficiency Defect in chromsome 17
84
What is mode of inheritance of Mekes disease
X-linked recessive disease (only in boys) Impaired uptake of copper
85
What is the triad of holocarboxylase synthetase or biotinidase deficiency
Alopecia Skin rash (similar to acrodermatitis enteropathica) Encephalopathy
86
What is the bone marrow finding in niemann-pick
Foam cells
87
Which lysosomal disease presents as infantile neurodegeneration (inc muscle tone, profound irritabililty, FUO)
Krabbe disease
88
Which GSD presents with heart failure, respiratory insuffiency, death
Pompe disease - accumulation of glycogen in lysosome of muscles CK elevated, shortened P-R interval
89
How are mitochondrial disorders transmitted
Point mutation in mitochondrial genome via maternal inheritance (**Passed from mom**) ## Footnote **Mode of inheritance: autosomal recessive**
90
most important function of mitochondria
production of cellular energy in the form of ATP from respiratory chain - result: dysfuntion in tissue with highes energy demand (brain, skeletal, cardiac)
91
lab findings in mitochondrial do
Lactic acidosis (metabolic acidosis) MELaS- myophathy, encephalopathy, lactic acidosis, stroke Ragged red fibers (muscle myopathy)
92
What is the defect in Wilsons disease
Hepatic copper transport Deposition of copper in liver, cornea, basal ganglia, renal tubules Mode of inheritance: Autosomal recessive
93
What are the clinical symptoms of Wilsons
hepatic disease neurologic hemolysis, dyarthria, extrapyramidal movement kayser fleischer ring (eye exam)
94
What is the defect in Menkes disease
Defect in copper membrane transport channel leading to **poor absorption and distribution of copper**
95
What is the treatment for Wilsons
D-penicillamine (chelate copper)
96
What are the clinical symptoms of Menkes
Brittle kinky steely hair Pudy sagging lips abN eyebrow skin and joint laxity, wormian bones, osteoporosis
97
Diagnosis of Wilson and Menkes
Low ceruloplasmin genetic testing
98
What are peroxisome
cellular organelle with disparate function: oxidation of very long chain fatty acids results in neurodegenerative do
99
what is Zellweger syndrome
also known as neonatal adrenoleukodystrophy findings: 1. dysmorphic features (prominent forehead, wide open fontanel, hypertelorism, broad flat nasal brdige, micrognathia) 2. liver disease, cholestasis 3. bone involvement (calcified stippling) 4. hypotonia 5. hearing and vision deficits
100
What is the deficiency in galactosemia type II
Galactokinase -Long term complication: Cataract and psuedotumor cerebri (due to osmotic effect of galactitol)
101
What is deficient in Niemann-Pick
Sphingomyelinase
102
What is the defect in Gaucher
Glucocerbrosidase
103
symptoms of biotinidase deficiency
neuro: seizure, hypotonia, ataxia, blindness, hearing loss immune deficit alopecia developmental delay
104
Sugar found in: a. breastmilk b. formula
a. lactose (galactose and glucose) b. lactose plus sucrose (fructose and glucose)
105
findings in transient hyperammonemia of the newborn
elevated ammonia in the 1st 24 HOL normal PAA No acidosis
106
What medication can be considered for refractory seizures?
Pyridoxine (Consider possible inborn error of metabolism- cofactor ir vitmain deficiency) Caution: apnea and respiratory compromise may occur during administration