What condition is characterized by tightening of connective tissue?

Scleroderma is the correct answer because it primarily involves the tightening and hardening of the skin and connective tissues, resulting from an overproduction of collagen. This condition can affect various parts of the body and lead to symptoms such as skin thickening, joint stiffness, and internal organ involvement. The hallmark of scleroderma is the excessive collagen deposition that leads to fibrosis, which significantly compromises normal tissue function.

In contrast, polymyositis is an inflammatory disease that targets the muscles specifically, causing weakness and inflammation without the characteristic tightening of connective tissue. Rheumatoid arthritis is an autoimmune condition that primarily affects the joints, leading to pain and swelling but does not specifically involve the extensive connective tissue tightening seen in scleroderma. Juvenile rheumatoid arthritis refers to the form of arthritis that occurs in children and primarily affects joint health, also not presenting the connective tissue tightening associated with scleroderma.