ABGC Boards: Metabolics Exam Questions and
Answers 100% Pass
What causes inborn errors of metabolism? - ✔✔Enzyme deficiencies
What causes the symptoms of IEMs? - ✔✔1. Accumulation of substrate, or
2. Deficiency of product
T/F: Individuals with IEMs usually have dysmorphic features - ✔✔F
What is the usual inheritance pattern of IEMs? - ✔✔Recessive
T/F: IEMs usually have effective treatment options - ✔✔T
Why are IEMs common targets of NBS? - ✔✔Effective, preventive treatments available
What is the defect in PKU? - ✔✔Defect in phenylalanine hydroxylase, which converts phenylalanine to
tyrosine
What does high phenylalanine cause? - ✔✔Accumulation of phenylketones
What is the most common defect in CAH? - ✔✔Defect in 21-hydroxylase, which converts 17-
hydroxyprogesterone into 11-deoxycortisol
What does high 17-hydroxyprogesterone cause? - ✔✔Virilization in utero
What is treatment for IEMs based on? - ✔✔Correcting metabolic imbalances
With IEMs, how much enzyme activity is usually needed to avoid symptoms? - ✔✔~10% of normal
activity
Which test is better for quantitative analysis of amino acids - plasma or urine? - ✔✔Plasma
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,What circumstances are best for amino acid analysis? - ✔✔Fasting specimen
What specimen is usually used for organic acid analysis? - ✔✔Urine
Is organic acid analysis qualitative or quantitative? - ✔✔Can be either!
What are examples of clinical scenarios in which amino acids and/or organic acids may be ordered? -
✔✔FTT, unexplained acute illness, DD, monitoring of therapies for known IEMs
What specimen is usually used for acylcarnitine profile? - ✔✔Plasma
How are acylcarnitines usually reported? - ✔✔By carbon chain length and number of double bonds
What types of specimens might be used for enzyme assays? - ✔✔WBCs, newborn blood spots, fibroblast
bx and culture, liver bx, muscle bx
What type of mutations do partial activity mutants usually have? - ✔✔Point mutations resulting in
reduced enzyme activity
What type of mutations usually result in absence of protein? - ✔✔Deletions, splice junctions, premature
stop mutations
What are the pros of enzyme testing? - ✔✔Less expensive, not dependent on particular mutations
What are the cons of enzyme testing? - ✔✔Enzyme activity may not be stable, enzyme may not be
expressed in accessible tissues
What are the two types of genetic heterogeneity? - ✔✔1. Non-allelic/locus
2. Allelic
What is non-allelic/locus heterogeneity? - ✔✔Mutations in different genes cause same phenotype
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, What are examples of metabolic conditions with non-allelic heterogeneity? - ✔✔MPS, methylmalonic
aciduria, homocystinuria, propionic acidemia
What is allelic heterogeneity? - ✔✔Different mutations at same locus cause same phenotype
What are examples of metabolic conditions with allelic heterogeneity? - ✔✔PKU
What are examples of symptoms in neonatal onset IEMs? - ✔✔-Vomiting
-Lethargy
-Coma
-Severe acidosis (low blood pH)
-Respiratory distress
-Weakness
-Hypoglycemia
-Hepatomegaly
-Seizures
What is respiratory distress in IEMs caused by? - ✔✔Response to accumulated metabolites
What are the general principles that suggest an acutely ill newborn might have an IEM? - ✔✔-Full term
pregnancy
-Good APGARs
-Non-dysmorphic
-Normal for first 24-48 hrs
Page 3/16
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Answers 100% Pass
What causes inborn errors of metabolism? - ✔✔Enzyme deficiencies
What causes the symptoms of IEMs? - ✔✔1. Accumulation of substrate, or
2. Deficiency of product
T/F: Individuals with IEMs usually have dysmorphic features - ✔✔F
What is the usual inheritance pattern of IEMs? - ✔✔Recessive
T/F: IEMs usually have effective treatment options - ✔✔T
Why are IEMs common targets of NBS? - ✔✔Effective, preventive treatments available
What is the defect in PKU? - ✔✔Defect in phenylalanine hydroxylase, which converts phenylalanine to
tyrosine
What does high phenylalanine cause? - ✔✔Accumulation of phenylketones
What is the most common defect in CAH? - ✔✔Defect in 21-hydroxylase, which converts 17-
hydroxyprogesterone into 11-deoxycortisol
What does high 17-hydroxyprogesterone cause? - ✔✔Virilization in utero
What is treatment for IEMs based on? - ✔✔Correcting metabolic imbalances
With IEMs, how much enzyme activity is usually needed to avoid symptoms? - ✔✔~10% of normal
activity
Which test is better for quantitative analysis of amino acids - plasma or urine? - ✔✔Plasma
Page 1/16
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,What circumstances are best for amino acid analysis? - ✔✔Fasting specimen
What specimen is usually used for organic acid analysis? - ✔✔Urine
Is organic acid analysis qualitative or quantitative? - ✔✔Can be either!
What are examples of clinical scenarios in which amino acids and/or organic acids may be ordered? -
✔✔FTT, unexplained acute illness, DD, monitoring of therapies for known IEMs
What specimen is usually used for acylcarnitine profile? - ✔✔Plasma
How are acylcarnitines usually reported? - ✔✔By carbon chain length and number of double bonds
What types of specimens might be used for enzyme assays? - ✔✔WBCs, newborn blood spots, fibroblast
bx and culture, liver bx, muscle bx
What type of mutations do partial activity mutants usually have? - ✔✔Point mutations resulting in
reduced enzyme activity
What type of mutations usually result in absence of protein? - ✔✔Deletions, splice junctions, premature
stop mutations
What are the pros of enzyme testing? - ✔✔Less expensive, not dependent on particular mutations
What are the cons of enzyme testing? - ✔✔Enzyme activity may not be stable, enzyme may not be
expressed in accessible tissues
What are the two types of genetic heterogeneity? - ✔✔1. Non-allelic/locus
2. Allelic
What is non-allelic/locus heterogeneity? - ✔✔Mutations in different genes cause same phenotype
Page 2/16
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, What are examples of metabolic conditions with non-allelic heterogeneity? - ✔✔MPS, methylmalonic
aciduria, homocystinuria, propionic acidemia
What is allelic heterogeneity? - ✔✔Different mutations at same locus cause same phenotype
What are examples of metabolic conditions with allelic heterogeneity? - ✔✔PKU
What are examples of symptoms in neonatal onset IEMs? - ✔✔-Vomiting
-Lethargy
-Coma
-Severe acidosis (low blood pH)
-Respiratory distress
-Weakness
-Hypoglycemia
-Hepatomegaly
-Seizures
What is respiratory distress in IEMs caused by? - ✔✔Response to accumulated metabolites
What are the general principles that suggest an acutely ill newborn might have an IEM? - ✔✔-Full term
pregnancy
-Good APGARs
-Non-dysmorphic
-Normal for first 24-48 hrs
Page 3/16
Crafted for Academic Insight by KatelynWhitman. All rights reserved © 2025
