Inborn Errors of Metabolism

Question 1

Why does newborn crash occur in patients with metabolic diseases?

Answer 1

Prior to birth the placenta filters the fetus’ blood

Question 2

What is the main cause of newborn crash?

Answer 2

Sepsis

Question 3

A baby presents at 4 days of life with lethargy and decreased p.o. intake. A septic workup is negative. He is noted to have a blood gas with a ph of 7.49. The NH3 is 1200. What is the most likely diagnosis?

A. Ornithine Transcarbamylase deficiency
B. Maple Syrup Urine Disease
C. MCAD
D. Galactosemia
E. Phenylketonuria (PKU)

Answer 3

A. Ornithine Transcarbamylase deficiency

Question 4

What are some of the causes of normal anion gap metabolic acidosis?

Answer 4

• Diarrhea

- Renal tubular acidosis

Question 5

What group of diseases are the following associated with:

 Methylmalonic
 Isovaleric
 Proprionic
 Glutaric acidemia

Answer 5

Organic Acidemias

Question 6

What is the function of phenylalanine hydroxylase?

Answer 6

Converts phenylalanine to tyrosine

Question 7

What converts arginine to ornithine?

Answer 7

Arginase

Question 8

What is the pH of a patient with a urea cycle defect?

Answer 8

Alkalotic (greater than 7.45)

Question 9

What can agenesis of the corpus collosum indicate?

Answer 9

Nonketoic Hyperglycinemia

Question 10

What is the inheritance of Maple Syrup Urine disease?

Answer 10

Autosomal Recessive

Question 11

What group of people is more commonly affected by Maple Syrup Urine disease?

Answer 11

Mennonites

Question 12

What is the urine smell of tyrosinemia?

Answer 12

Rotten Cabbage

Question 13

A 6 month old presents to the ER with lethargy. He was diagnosed with a viral illness 3 days prior. He had poor p.o. intake for the past 2 days. Initial laboratory studies showed glucose of 50. Blood gas showed Ph 7.38, CO2 21. The lactic acid was 1.8, NH3 was 80. The urine dip was negative for ketones. The most likely diagnosis:

A. Ornithine Transcarbamylase deficiency
B. Maple Syrup Urine Disease
C. MCAD
D. Galactosemia
E. Phenylketonuria (PKU)

Answer 13

C. MCAD

Question 14

What is Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency?

Answer 14

•  Classic disorder of fatty acid oxidation
•  Most common of the FA oxidation disorders
• Patients cannot break down fat

Question 15

•  Megalencephaly
• MRI abnormalities including lesions to the basal ganglia and subdural hematoma
• Acidemia

Answer 15

Glutaric Acidemia

Question 16

A newborn begins vomiting after feeding and is severely jaundiced. Treatment for possible sepsis is initiated. A blood screen of galactosemia is positive. Which of the following studies would also be expected?

A. Urine amino acids will show an elevation of phenyalanine
B. Urine organic acids will show elevation of branched chain
amino amino acids
C. Lactic acid will be elevation
D. Urine will be positive for reducing substances
E. Blood culture will indicate Streptococcal sepsis

Answer 16

D. Urine will be positive for reducing substances

Question 17

What is galactose converted to if it cannot be converted to glucose?

Answer 17

Galactitol

Question 18

What are the features of galactosemia?

Answer 18

• E. coli sepsis
• Jaundice
• Hepatosplenomegaly
• Cataracts

Question 19

What is the treatment for galactosemia?

Answer 19

Lactose free diet - no breastfeeding and must use a soy formula

Question 20

Von Gierke Disease - Glycogen Storage Disease Type I

Answer 20

Cannot convert glucose-6-phosphate to glucose - glucose-6-phosphatase deficiency

Question 21

McArdle Disease - Glycogen Storage Disease Type V

Answer 21

Deficiency of the enzyme muscle phosphorylase which results in reduced ATP generation by glycogenolysis.

Question 22

A college student comes into clinic. He recently started a weight lifting program. After a 30 minute work out he experiences severe pain which has not improved over the past week. The day prior he had red colored urine. A urine dip is negative for blood. A CK was noted to be elevated at 600. What is the most likely diagnosis?

A. Beckers Muscular Dystrophy
B. MCAD
C. Galactosemia
D. Pompe Disease
E. McArdles Disease

Answer 22

E. McArdles Disease

Question 23

What color urine can be seen with McArdle disease?

Answer 23

Burgundy colored urine - muscle breakdown NOT blood