In which disease is excess glycosaminoglycans a key feature?

Hunter syndrome, also known as mucopolysaccharidosis type II (MPS II), is characterized by the accumulation of glycosaminoglycans (GAGs) in the body due to a deficiency of the enzyme iduronate-2-sulfatase. This enzyme is responsible for breaking down specific GAGs, and its deficiency leads to the abnormal buildup of these molecules, resulting in various systemic and neurological symptoms.

The presence of excess GAGs is central to the diagnosis of Hunter syndrome and affects multiple organ systems, causing a range of clinical manifestations, including skeletal abnormalities, cardiovascular issues, and developmental delays. Recognizing this accumulation is critical for both diagnosis and management of the disease.

Although there are other metabolic disorders listed that involve amino acid or metabolic abnormalities, they do not feature the excess accumulation of glycosaminoglycans as a primary characteristic, making Hunter syndrome the correct answer.