Proteus syndrome is an extremely rare but chronic, or long-term, condition. It causes an overgrowth of skin, bones, blood vessels, and fatty and connective tissue. These overgrowths usually aren’t cancerous.

The overgrowths can be mild or severe, and they can affect any part of the body. The limbs, spine, and skull are most commonly affected. They typically aren’t apparent at birth, but become more noticeable by age 6 to 18 months. Left untreated, the overgrowths can lead to serious health and mobility issues.

It’s estimated that fewer than 500 people worldwide have Proteus syndrome.

Did you know?

Proteus syndrome got its name from the Greek god Proteus, who would change his shape to elude capture. It’s also thought that Joseph Merrick, the so-called Elephant Man, had Proteus syndrome.

Symptoms tend to vary greatly from one person to another and can include:

  • asymmetric overgrowths, such as one side of the body having longer limbs than the other
  • raised, rough skin lesions that may have a bumpy, grooved appearance
  • a curved spine, also called scoliosis
  • fatty overgrowths, often on the stomach, arms, and legs
  • noncancerous tumors, often found on the ovaries, and membranes that cover the brain and spinal cord
  • malformed blood vessels, which increase the risk of life-threatening blood clots
  • malformation of the central nervous system, which can cause mental disabilities, and features such as a long face and narrow head, droopy eyelids, and wide nostrils
  • thickened skin pads on the soles of the feet

Proteus syndrome occurs during fetal development. It’s caused by what experts call a mutation, or permanent alteration, of the gene AKT1. The AKT1 gene helps regulate growth.

No one really knows why this mutation occurs, but doctors suspect it’s random and not inherited. For this reason, Proteus syndrome isn’t a disease that is passed on from one generation to the next. The Proteus Syndrome Foundation emphasizes that this condition isn’t causes by something a parent did or didn’t do.

Scientists have also discovered that the gene mutation is mosaic. That means it affects some cells in the body but not others. This helps to explain why one side of the body may be affected and not the other, and why the severity of symptoms can vary so greatly from one person to another.

Diagnosis can be difficult. The condition is rare, and many doctors are unfamiliar it. The first step a doctor may take is to biopsy a tumor or tissue, and test the sample for the presence of a mutated AKT1 gene. If one is found, screening tests, such as X-rays, ultrasounds, and CT scans, may be used to look for internal masses.

There’s no cure for Proteus syndrome. Treatment generally focuses on minimizing and managing symptoms.

The condition affects many parts of the body, so your child may need treatment from several doctors, including the following:

  • cardiologist
  • dermatologist
  • pulmonologist (lung specialist)
  • orthopedist (bone doctor)
  • physical therapist
  • psychiatrist

Surgery to remove skin overgrowths and excess tissue may be recommended. Doctors may also suggest surgically removing growth plates in the bone to prevent excessive growth.

Proteus syndrome can cause numerous complications. Some can be life-threatening.

Your child may develop large masses. These can be disfiguring and lead to severe mobility issues. Tumors can compress organs and nerves, resulting in things like a collapsed lung and loss of sensation in a limb. Overgrowth of bone can also lead to loss of mobility.

The growths can also cause neurological complications that may affect mental development, and lead to loss of vision and seizures.

People with Proteus syndrome are more prone to deep vein thrombosis because it can affect blood vessels. Deep vein thrombosis is a blood clot that occurs in the body’s deep veins, usually in the leg. The clot can break free and travel throughout the body.

If a clot becomes wedged in an artery of the lungs, called a pulmonary embolism, it can block blood flow and lead to death. Pulmonary embolism is a leading cause of death in people with Proteus syndrome. Your child will regularly be monitored for blood clots. Common symptoms of a pulmonary embolism are:

  • shortness of breath
  • chest pain
  • a cough that can sometimes bring up blood-streaked mucus

Proteus syndrome is a very uncommon condition that can vary in severity. Without treatment, the condition will worsen over time. Treatment may include surgery and physical therapy. Your child will also be monitored for blood clots.

The condition can affect quality of life, but people with Proteus syndrome can age normally with medical intervention and monitoring.