Biochem & Storage Diseases

Question 1

Infant with hypoglycemia and vomiting after ingestion of new food. Dx’d as an aldolase B deficiency. What disorder is this and what food must be avoided?

Answer 1

Hereditary fructose intolerance

Avoid sucrose and fructose

Question 2

This increases orotic acid in urine, causes a megaloblastic anemia, and does NOT have hyperammonemia. Symptoms are not improved by Vit B12 supplmentation. What enzyme is deficient?

How do you treat this?

Answer 2

UMP Synthase deficiency
(Orotic aciduria)

Tx: Uridine supplementation (diet)

Question 3

Increased orotic acid in urine with hyperammonemia is a deficiency in what enzyme?

Answer 3

Ornithine transcarbamylase

Question 4

A child has mental retardation, hyperuremia, aggressive behavior, and intense biting of the lip. What enzyme is deficiency and what pathway does this effect? Whats the inheritance pattern?

Answer 4

Lesch-Nyhan Syndrome

*HGPRT enzyme deficiency used in purine salvage pathway
He’s got purine recovery troubles –> also shows its X-linked

Question 5

There is a newborn with chronic diarrhea, failure to thrive, and chronic candidiasis. What disorder do you suspect and what enzyme is deficient?

Answer 5

SCID

*Adenosine deaminase deficiency

Question 6

The following enzymes in the pyrimidine and purine synthesis pathways are inhibited by what drugs?

1. Ribonucleotide reductase
2. Dihydrofolate reductase
3. Thymidylate synthase
4. Inosine monophosphate dehydrogenase
5. PRPP amidotransferase

Answer 6

1. Ribonucleotide reductase
   - -Hydroxyurea
2. Dihydrofolate reductase
   - -Trimethoprim, Methotrexate
3. Thymidylate synthase
   - -5-Fluorouracil
4. Inosine monophosphate dehydrogenase
   - -Mycophenalate
5. PRPP amidotransferase
   - -6-Mercaptopurine

Question 7

An infant has corneal clouding, coarse facies, HSM, skeletal abnormalities, and restricted joints. What is deficient in this child?

Answer 7

Mannose-6-phosphate

Called I-disease (Inclusion cell disease)