VHL Gene

Von Hippel-Lindau syndrome is an inherited disorder characterized by the formation of tumors and fluid-filled sacs (cysts) in many different parts of the body. Tumors may be either noncancerous or cancerous and most frequently appear during young adulthood; however, the signs and symptoms of von Hippel-Lindau syndrome can occur throughout life.

Tumors called hemangioblastomas are characteristic of von Hippel-Lindau syndrome. These growths are made of newly formed blood vessels. Although they are typically noncancerous, they can cause serious or life-threatening complications. Hemangioblastomas that develop in the brain and spinal cord can cause headaches, vomiting, weakness, and a loss of muscle coordination (ataxia). Hemangioblastomas can also occur in the light-sensitive tissue that lines the back of the eye (the retina). These tumors, which are also called retinal angiomas, may cause vision loss.

People with von Hippel-Lindau syndrome commonly develop cysts in the kidneys, pancreas, and genital tract. They are also at an increased risk of developing a type of kidney cancer called clear cell renal cell carcinoma and a type of pancreatic cancer called a pancreatic neuroendocrine tumor.

Von Hippel-Lindau syndrome is associated with a type of tumor called a pheochromocytoma, which most commonly occurs in the adrenal glands (small hormone-producing glands located on top of each kidney). Pheochromocytomas are usually noncancerous. They may cause no symptoms, but in some cases they are associated with headaches, panic attacks, excess sweating, or dangerously high blood pressure that may not respond to medication. Pheochromocytomas are particularly dangerous in times of stress or trauma, such as when undergoing surgery or in an accident, or during pregnancy.

About 10 percent of people with von Hippel-Lindau syndrome develop endolymphatic sac tumors, which are noncancerous tumors in the inner ear. These growths can cause hearing loss in one or both ears, as well as ringing in the ears (tinnitus) and problems with balance. Without treatment, these tumors can cause sudden profound deafness.

Noncancerous tumors may also develop in the liver and lungs in people with von Hippel-Lindau syndrome. These tumors do not appear to cause any signs or symptoms.

Familial erythrocytosis is an inherited condition characterized by an increased number of red blood cells (erythrocytes). The primary function of these cells is to carry oxygen from the lungs to tissues and organs throughout the body. Signs and symptoms of familial erythrocytosis can include headaches, dizziness, nosebleeds, and shortness of breath. The excess red blood cells also increase the risk of developing abnormal blood clots that can block the flow of blood through arteries and veins. If these clots restrict blood flow to essential organs and tissues (particularly the heart, lungs, or brain), they can cause life-threatening complications such as a heart attack or stroke. However, many people with familial erythrocytosis experience only mild signs and symptoms or never have any problems related to their extra red blood cells.

Paraganglioma is a type of noncancerous (benign) tumor that occurs in structures called paraganglia. Paraganglia are groups of cells that are found near nerve cell bunches called ganglia. Paragangliomas are usually found in the head, neck, or torso. However, a type of paraganglioma known as pheochromocytoma develops in the adrenal glands. Adrenal glands are located on top of each kidney and produce hormones in response to stress. Most people with paraganglioma develop only one tumor in their lifetime.

Some people develop a paraganglioma or pheochromocytoma as part of a hereditary syndrome that may affect other organs and tissues in the body. However, the tumors often are not associated with any syndromes, in which case the condition is called nonsyndromic paraganglioma or pheochromocytoma.

Pheochromocytomas and some other paragangliomas are associated with ganglia of the sympathetic nervous system. The sympathetic nervous system controls the "fight-or-flight" response, a series of changes in the body due to hormones released in response to stress. Although most sympathetic paragangliomas are pheochromocytomas, some are found outside the adrenal glands, usually in the abdomen, and are called extra-adrenal paragangliomas. Most sympathetic paragangliomas, including pheochromocytomas, produce hormones called catecholamines, such as epinephrine (adrenaline) or norepinephrine. These excess catecholamines can cause signs and symptoms such as high blood pressure (hypertension), episodes of rapid heartbeat (palpitations), headaches, or sweating.

Most paragangliomas are associated with ganglia of the parasympathetic nervous system, which controls involuntary body functions such as digestion and saliva formation. Parasympathetic paragangliomas, typically found in the head and neck, usually do not produce hormones. However, large tumors may cause signs and symptoms such as coughing, hearing loss in one ear, or difficulty swallowing.

Although most paragangliomas and pheochromocytomas are noncancerous, some can become cancerous (malignant) and spread to other parts of the body (metastasize). Extra-adrenal paragangliomas become malignant more often than other types of paraganglioma or pheochromocytoma.