EK 1001 Biology #985

[apgar]

An untreated newborn diagnosed with classical galactosemia is expected to have an accumulation of which of the following substances in the blood?

A. galactose only
B. galactose-1-phosphate only
C. both galactose and galactose-1-phosphate
D. neither galactose nor galactose-1-phosphate


The answer listed is C. However, the passage states that classical galactosemia has a defective galactokinase protein. How can there be an accumulation of galactose-1-phosphate is the enzyme leading to this product is defective? The answer key does not really address this. Am I simply overthinking this?

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[MiCasaMD]

An untreated newborn diagnosed with classical galactosemia is expected to have an accumulation of which of the following substances in the blood?

A. galactose only
B. galactose-1-phosphate only
C. both galactose and galactose-1-phosphate
D. neither galactose nor galactose-1-phosphate


The answer listed is C. However, the passage states that classical galactosemia has a defective galactokinase protein. How can there be an accumulation of galactose-1-phosphate is the enzyme leading to this product is defective? The answer key does not really address this. Am I simply overthinking this?

General Discussion Galactosemia is a rare, hereditary disorder of carbohydrate metabolism that affects the body's ability to convert galactose (a sugar contained in milk, including human mother's milk) to glucose (a different type of sugar). Galactose is converted to glucose by a series of three enzyme reactions. The disorder is caused by a deficiency of an enzyme known as "galactose-1-phosphate uridyl transferase" which is vital to this process. Galactosemia may also be referred to as classic galactosemia because a few variants of the gene for galactosemia have been identified. One variant causes a milder form of the disorder known as Duarte galactosemia. Classic galactosemia is the most severe form. Synonyms * Galactose-1-Phosphate Uridyl Transferase Deficiency * GALT Deficiency * Classic Galactosemia * Galactokinase deficiency * Galactose-6-phosphatase emirase deficiency Source: WebMD

 

[Salient]

Yeah, so GALT is the enzyme that converts galactose 1 phosphate to glucose 1 phosphate... a GALT deficiency would probably lead to C depending on where the equilibrium for the kinase sits, but that's not what you say the passage said. Could you post the whole passage here? I don't have the EK book.