Causes of Acromegaly

Acromegaly is a rare hormonal disorder that results from the excessive production of growth hormone by the pituitary gland. The pituitary gland is a small, pea-sized structure located at the base of the brain, just below the hypothalamus.

The pituitary gland is often referred to as the “master gland” because it produces several hormones that regulate many important bodily functions. One key function of the pituitary gland is regulating the amount of growth hormone in the bloodstream. 

Excess growth hormone stimulates the liver to produce insulin-like growth factor 1 (IGF-1), another type of hormone. In a person with acromegaly, this excessive production of growth hormone leads to an elevated level of IGF-1 in the blood, which can contribute to the characteristic symptoms of the disorder, which includes enlarged hands and facial features.

Given the significance of our hands and feet in our daily lives, even basic tasks such as writing with pen and paper, or buttoning a shirt button can pose a challenge for someone living with acromegaly. Here, we explore the different causes of acromegaly and address common questions that patients may have.

• Pituitary Tumors—The most common cause of acromegaly is a non-cancerous (benign) tumor on the pituitary gland, known as a pituitary adenoma. A pituitary adenoma can trigger the pituitary gland to produce excess growth hormone, leading to abnormal growth of the tissues of the body.  
• Other Tumors—In more rare cases, a tumor outside of the pituitary gland, such as in the pancreas, lungs, or adrenal glands, can result in an excessive amount of growth hormone-releasing hormone, which stimulates the pituitary gland to produce more growth hormone.

Very rarely, acromegaly can manifest as a part of another genetic disorder. One such disorder is Carney complex.

This rare genetic disorder causes the formation of multiple benign tumors, including pituitary adenomas, that can lead to acromegaly. In addition, McCune–Albright syndrome, a rare genetic disorder that causes abnormal bone growth and skin pigmentation, can also cause pituitary tumors and acromegaly.

Certain environmental factors might indirectly influence the risk of developing a pituitary tumor, which can lead to acromegaly. For example, high-dose radiation therapy to the head or neck region, such as for the treatment of a previous tumor, can increase the risk of developing a pituitary tumor. This is a very rare situation.

There is ongoing research to understand the potential role of environmental factors such as exposure to certain chemicals in the development of pituitary tumors. However, conclusive evidence linking specific environmental factors to pituitary tumor development is currently lacking.  

Acromegaly can affect people of any age, sex, or ethnicity. However, it is relatively rare compared with other hormonal disorders. The onset of acromegaly typically occurs in adulthood between the ages of 30 and 50 years, but it can develop in a person at any age.

Both men and women can be affected by acromegaly, and there is no significant sex bias in its occurrence. The disorder does not seem to be more frequent in any specific population or ethnic group. It is estimated to affect approximately 40 to 125 individuals per million people, regardless of their demographics. 

Since most cases of acromegaly are caused by the presence of a pituitary adenoma, there is no known ways to prevent the condition. However, routine medical check-ups and screenings can aid in the early detection of an adenoma.

If you have a family history of pituitary tumors or any of the genetic syndromes associated with acromegaly, it is important to inform your health care provider, because he or she might recommend specific screenings or monitoring.

Acromegaly is not a direct result of hyperthyroidism. The primary cause of the disorder is excessive production of growth hormone from a pituitary adenoma.

In contrast, hyperthyroidism occurs when the thyroid gland becomes overactive and produces an excess amount of thyroid hormones, specifically thyroxine (T4) and triiodothyronine (T3). Hyperthyroidism can lead to various symptoms such as weight loss, increased heart rate, and even tremors.

• Acromegaly is caused primarily by the presence of a pituitary adenoma, a benign tumor that grows on the pituitary gland
• In most cases, pituitary adenomas develop sporadically with no clear cause
• No clear link exists between acromegaly and environmental factors
• The onset of acromegaly typically occurs in adulthood, usually between the ages of 30 and 50 years
• Although acromegaly can occur in anyone, certain risk factors, such as a family history of pituitary tumors or a genetic syndrome, can increase the likelihood of developing the disorder

• Pituitary Network Association: Acromegaly
• The Pituitary Foundation [UK]: Acromegaly
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Acromegaly
• National Health Service (NHS) [UK]: Acromegaly