What disorder is associated with defects in glucosylcerebrosidase?

Gaucher disease is directly linked to defects in the enzyme glucosylcerebrosidase. This enzyme is responsible for the metabolism of glucocerebroside, a type of lipid. When glucosylcerebrosidase is deficient or dysfunctional, glucocerebroside accumulates, leading to a range of symptoms including enlargement of the liver and spleen, bone disorders, and in some cases, neurological problems.

In the context of the other disorders mentioned, Tay-Sachs disease is associated with a deficiency in hexosaminidase A, which leads to the accumulation of GM2 gangliosides in nerve cells. Fabry disease results from a deficiency in alpha-galactosidase A, leading to the accumulation of globotriaosylceramide. Krabbe disease is caused by a deficiency in galactocerebrosidase, which is responsible for the breakdown of galactocerebroside.

Thus, Gaucher disease stands out as the disorder specifically characterized by defects in glucosylcerebrosidase, which helps clarify why this answer is the correct choice.