Final answer:
Galactokinase deficiency results in the build-up of galactose in the blood and its subsequent excretion via urine, known as galactosuria. It is a genetic disorder that impedes the conversion of galactose to glucose due to lack of the enzyme galactokinase.
Step-by-step explanation:
The sole manifestation of galactokinase deficiency is galactosuria, which is characterized by the presence of galactose in the urine. Galactokinase deficiency is a less common and milder form of galactosemia, a genetic disease that prevents the body from converting galactose into glucose. This condition is different from lactose intolerance, where the individual lacks lactase, an enzyme that breaks down lactose found in milk. In contrast, galactokinase deficiency specifically leads to a build-up of galactose in the blood, as the pathway to metabolize galactose into glucose, for which galactokinase is crucial, is impaired. Consequently, the excess galactose is excreted in the urine, leading to galactosuria.