Acromegaly is characterized by excess growth hormone (GH) production, leading to increased growth in bone and soft tissue and other disturbances throughout the body. In children, excess GH causes exceptional growth of long bones. This variant is called gigantism, because the additional bone growth causes unusual height. When too much GH is produced after a person has already reached adult height, the disorder is called acromegaly. Acromegaly is rare, affecting approximately 50 out of every 1 million people. Both men and women are affected. Because symptoms occur gradually, most patients are not identified until they are middle aged.

GH is one of several hormones produced by the pituitary gland, which is located in the brain. Pituitary hormones are involved in many activities throughout the body, including growth regulation and reproductive functions. Under normal conditions, the pituitary's activity is directed by the hypothalamus, a small structure located...