Question

An infant presents with vomiting after feeding. A Benedict’s test was performed and returned positive for a non-glucose substance. Which of the following is the most likely diagnosis?

• A. Galactosemia due to GAL-1-P uridyl transferase enzyme deficiency
• B. Hereditary fructose intolerance due to aldolase B deficiency
• C. Glucose-6-Phosphate dehydrogenase (G6PD) deficiency
• D. Galactosemia due to galactokinase enzyme deficiency

Hint:

In infants with vomiting after feeding and a positive Benedict's test, consider galactosemia. The absence of GAL-1-P uridyl transferase enzyme activity is the most common cause.

Answer 1

The Correct Option is A

The positive Benedict's test for a non-glucose substance suggests a metabolic disorder involving sugar metabolism. This clinical presentation, along with vomiting after feeding, is highly indicative of galactosemia, specifically due to GAL-1-P uridyl transferase enzyme deficiency. Galactosemia is an inborn error of metabolism that affects the body's ability to metabolize galactose, a component of lactose found in milk. Without proper metabolism, galactose accumulates in the body, leading to symptoms such as vomiting, failure to thrive, and hepatomegaly.
- Hereditary fructose intolerance involves a deficiency of aldolase B and presents with similar symptoms such as vomiting and hypoglycemia but does not typically show a positive Benedict's test for non-glucose substances.
- G6PD deficiency leads to hemolysis, especially following oxidative stress (like certain infections or drugs), but does not cause the vomiting after feeding or positive Benedict’s test for non-glucose substances.
- Galactosemia due to galactokinase deficiency presents similarly but tends to cause cataracts rather than the severe manifestations seen with GAL-1-P uridyl transferase deficiency.
The definitive diagnosis for this infant is galactosemia due to GAL-1-P uridyl transferase enzyme deficiency.