Question

Galactosemia is a genetic defect in which an individual is unable to correctly metabolize galactose. This results in high galactose levels in the blood and galactose-1-phosphate in the tissues.

a. If you were a physician treating a person with this genetic disorder, what suggestions would you make to avoid high galactose levels in the blood?
b. Galactosemia is often a problem in infants. Why would infants be more likely to develop galactosemia?
c. From what you know about the metabolism of galactose can you suggest why galactosemia is more common than fructosemia?
d. Galactosemia is a genetic defect that results from a mutation that results in high levels of galactose-1-phosphate in the blood. The individual is unable to make fully functioning enzymes to metabolize galactose but can still metabolize starch and glycogen. Can you suggest a possible candidate for the flawed enzyme?

Answer 1

a. To manage galactosemia, dietary modifications are crucial, involving the exclusion of galactose-containing foods like milk. Substituting lactose-free alternatives and closely monitoring nutritional intake is advisable.

b. Infants are more prone to galactosemia as milk is a primary source of nutrition. Newborns lack the ability to metabolize galactose efficiently, leading to the accumulation of galactose and its derivatives.

c. Galactosemia is more common than fructosemia because the metabolism of galactose involves a series of enzymatic steps, and defects in any of these enzymes can lead to galactosemia. Fructose, on the other hand, has a simpler metabolic pathway.

d. The flawed enzyme in galactosemia is likely galactose-1-phosphate uridylyltransferase (GALT), which is essential for converting galactose-1-phosphate to glucose-1-phosphate.

Step-by-step explanation:

a. Management of Galactosemia: For individuals with galactosemia, dietary adjustments are critical. Since galactose is primarily found in milk, avoiding galactose-containing foods is essential. Lactose-free alternatives should be substituted, and close monitoring of nutritional intake is advisable.

b. Infants and Galactosemia: Galactosemia is often problematic in infants because milk, a primary source of nutrition, contains lactose. Newborns have underdeveloped galactose metabolism, leading to an inability to efficiently process galactose and subsequent accumulation of galactose and its derivatives.

c. Comparison with Fructosemia: Galactosemia is more common than fructosemia due to the complexity of galactose metabolism. Galactose undergoes a series of enzymatic conversions, and defects in any of these enzymes can result in galactosemia. In contrast, fructose has a simpler metabolic pathway, making fructosemia less common.

d. Flawed Enzyme in Galactosemia: The flawed enzyme in galactosemia is likely galactose-1-phosphate uridylyltransferase (GALT). This enzyme is crucial for converting galactose-1-phosphate to glucose-1-phosphate. While individuals with galactosemia cannot metabolize galactose properly, they can still metabolize starch and glycogen, suggesting that the defect lies in a specific enzyme within the galactose metabolic pathway.