What Is Proteus Syndrome?

Medically Reviewed by Dan Brennan, MD on February 20, 2024
Written by Rebekah Kuschmider
3 min read

Proteus syndrome is one of the rarest genetic conditions in the world. The syndrome causes abnormal overgrowth in certain parts of the body. It is commonly called the Elephant Man disease. ‌This overgrowth results in significant lifelong physical differences and potential disabilities. 

Proteus syndrome was identified as a condition in 1979, and there have not been many confirmed cases since then. The medical literature has identified about 200 people who have been diagnosed with the disease. At this time, experts estimate that one in a million people will have Proteus syndrome ‌.

Joseph Merrick, who was known as the Elephant Man and was the subject of a 1980 feature film of the same name, may have had Proteus syndrome. For some time, doctors thought he had neurofibromatosis, a disease that causes fibrous growths all over the body. In 1986, however, researchers determined that he most likely had Proteus syndrome. Merrick died in 1890.

Proteus syndrome is caused by a mutation in a specific gene called AKT1 and is present at birth. This gene makes a protein responsible for controlling cell growth. In some cases, the gene is altered, and so is the protein it makes. 

‌Experts believe the altered protein prevents cells from dying off at a normal rate. Instead of new cells replacing old ones, the new cells form in addition to the cells that haven't died off. That leads to overgrowth of portions of the body.

‌Proteus syndrome is known as a mosaic condition. This means that not all the cells in your body will have the altered AKT1 gene. Some cells have the alteration, but others do not. This is why overgrowth affects some areas of the body but not others. 

There are no known risk factors for Proteus syndrome. It doesn't run in families, and there is nothing parents can do to prevent it. 

Proteus syndrome symptoms don’t appear right away. Usually, though, there are signs of unusual growth within a child’s first six months of life. As time goes on, more signs of Proteus syndrome will emerge.

The most common signs of Proteus syndrome include:

  • Overgrowth of limbs or extremities
  • Raised, rough areas of skin 
  • Spinal curvatures (scoliosis)
  • Overgrowths of fatty tissue, often on the stomach, arms, and legs
  • Benign tumors in internal organs or the brain
  • Malformed blood vessels
  • Malformations of the central nervous system
  • Overgrowth of skin on the soles of the feet

All of these symptoms cause complications that affect daily living. Overgrowth of bones can lead to mobility issues. Skin lesions and fatty overgrowths can be very large and disfiguring. The overgrowth is usually asymmetrical - one one side - which can further complicate mobility or balance.

The overgrowth or malformation of blood vessels puts you at higher risk for pulmonary embolisms (blood clots in the lungs). Pulmonary embolism is a serious situation, one of the leading causes of death for people with Proteus syndrome.

People who have an overgrowth in their brain or spinal cord may have cognitive disabilities.

Nervous system issues from Proteus syndrome may lead to an unusual appearance characterized by a long, narrow head, droopy eyelids, and wide nostrils.

People who have Proteus syndrome need a medical team to manage their condition. You may need to visit multiple specialists, including a cardiologist, pulmonologist, orthopedist, dermatologist, physical therapist, or occupational therapist. 

Surgery to correct overgrowth is a common treatment for Proteus syndrome. You may need orthopedic procedures that can minimize the damage to joints so that you can retain as much mobility as possible. Surgeries to remove overgrowth of skin are also common for people with Proteus syndrome. Your doctors can help you decide what treatments will help you the most.