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 given scenario describes an infant who exhibits vomiting after feeding. The positive Benedict's test indicates the presence of a reducing sugar that is not glucose.

The conditions to consider are:

• Galactosemia due to GAL-1-P uridyl transferase enzyme deficiency: This condition results in the accumulation of galactose-1-phosphate, galactitol, and free galactose in the blood. Infants present with vomiting, jaundice, and hepatomegaly shortly after starting milk feeding. Galactose, being a reducing sugar, will lead to a positive Benedict’s test.
• Hereditary fructose intolerance due to aldolase B deficiency: Symptoms occur after the ingestion of fructose-containing foods, typically presenting later after weaning from breast milk, as it requires the ingestion of fructose. It does not match the immediate onset after feeding as described in the question.
• Glucose-6-Phosphate dehydrogenase (G6PD) deficiency: This condition is related to hemolytic anemia triggered by certain drugs, foods, or infections; it does not typically present with vomiting after feeding and does not cause a positive Benedict’s test.
• Galactosemia due to galactokinase enzyme deficiency: This causes accumulation of galactose in the blood, which also tests positive on Benedict's test, but is less severe compared to GAL-1-P uridyl transferase deficiency and primarily presents with cataracts.

The most likely diagnosis given the immediate and severe symptoms after milk ingestion and the positive Benedict's test for a non-glucose reducing substance is Galactosemia due to GAL-1-P uridyl transferase enzyme deficiency.