What endocrine disorder is caused by excessive secretion of growth hormone before skeletal maturity?

The condition caused by excessive secretion of growth hormone before skeletal maturity is known as gigantism. In children and adolescents, when growth plates have not yet fused, an overproduction of growth hormone leads to an accelerated growth rate, resulting in increased height and size. This is due to the stimulating effect of growth hormone on the growth plates of long bones, which allow for continued linear growth.

In contrast, acromegaly refers to the condition that occurs in adults when growth hormone secretion is excessive after the fusion of growth plates. It is characterized by bone enlargement and soft tissue swelling, but does not result in increased height as it does in the case of gigantism.

Pituitary dwarfism, on the other hand, is associated with inadequate secretion of growth hormone during childhood, leading to reduced growth and height.

Turner syndrome is a genetic condition affecting females, resulting from the absence of all or part of one X chromosome, and is characterized by short stature among other features, but it is not directly related to an excess of growth hormone.

Thus, the key to understanding why gigantism is the correct answer lies in recognizing the timing of growth hormone excess: it must occur before the closure of growth plates to result in increased height.