McCune-Albright syndrome affects the bones, skin, and endocrine system. A genetic mutation causes this rare condition, and people who have it are born with it.

Healthcare professionals often diagnose McCune-Albright syndrome in early childhood, when symptoms first appear. Symptoms range from mild to severe, and there is currently no cure. However, treatment can help people with this condition manage their symptoms and lead active lives.

McCune-Albright syndrome is a rare genetic condition that affects your bones, skin, and hormones. The condition is sometimes associated with fibrous dysplasia, a condition that causes bones, which have fibrous tissue within them, to grow where healthy bones usually grow.

People with McCune-Albright syndrome often experience fibrous dysplasia, increased hormone production, and patches of skin pigmentation known as café au lait spots.

Some people with McCune-Albright syndrome experience only mild symptoms, but other people with the condition have severe symptoms that impact their daily lives.

McCune-Albright syndrome affects three different body systems. People with the condition experience bone, skin, and hormonal, or endocrine system, symptoms. Not everyone with the condition will have every symptom, and the severity can vary.

Bone symptoms of McCune-Albright

Fibrous dysplasia is the most common bone symptom of McCune-Albright syndrome. It causes bones to grow with fibrous tissue inside them, which causes the surrounding matter to weaken. This leads to fractures and irregular growth.

Additional bone symptoms include:

Skin symptoms of McCune-Albright syndrome

McCune-Albright syndrome causes skin patches that are different colors than the surrounding skin. These patches are typically light to dark brown with jagged borders. They are known as café au lait spots. Often, people with McCune-Albright syndrome only have these spots on half their body. Spots can occur more often with age.

Endocrine system symptoms of McCune-Albright syndrome

The endocrine system is responsible for producing hormones. McCune-Albright syndrome causes an overproduction of hormones. This can cause a range of symptoms. Some children with McCune-Albright experience early puberty. For instance, girls with McCune-Albright can begin menstruating as early as 2 years old.

Other endocrine symptoms of McCune-Albright include:

A mutation of the GNAS1 gene causes McCune-Albright syndrome. This gene is responsible for making proteins that regulate hormonal activity. The mutation that leads to McCune-Albright causes the gene to make a protein that overproduces hormones.

This mutation isn’t hereditary. It appears to occur randomly. This means, it happens after conception and parents cannot pass the mutation to their children. So, parents with McCune-Albright syndrome don’t pass the condition on to their children, and there is no link to anything that is done, or not, during pregnancy.

In most cases, healthcare professionals diagnose McCune-Albright syndrome when a child is very young. A doctor might notice café au lait spots, early puberty, or irregular bone growth and then order tests to confirm a diagnosis. Some of the tests that might be done include:

  • Blood tests. A blood test can check for hormonal levels.
  • X-rays and other imaging tests. X-rays can look at bone growth and check for scarring.
  • Genetic testing. Genetic testing can look for the gene mutation that causes McCune-Albright.

There’s no cure yet for McCune-Albright syndrome. Treatment focuses on reducing symptoms. Since symptoms can vary widely between people, treatments can also vary. Doctors tailor treatment plans to address the symptoms of each person with McCune-Albright, and the plans might change as a person with McCune-Albright syndrome ages.

Potential treatments include:

  • physical therapy to reduce pain and help maintain strength
  • occupational therapy to help maintain mobility
  • osteoporosis medications such as alendronate to help reduce the risk of bone fractures
  • thyroid medications such as methimazole to help reduce symptoms linked to an enlarged thyroid
  • aromatase inhibitors such as Arimidex to help treat early puberty
  • surgery to help treat bone scarring

The outlook for people with McCune-Albright syndrome depends on the severity, but it’s rare for the condition to affect life expectancy. In most cases, you can manage the condition symptoms through treatment. Children and adults with McCune-Albright can generally lead active lives with minimal symptoms.

People with the McCune-Albright will usually need to have continuous treatment throughout their lives. There is an increased risk of both bone and breast cancer, so regular checkups and screenings can be vital.

Additionally, children with McCune-Albright can experience puberty much earlier than their peers. As a result of early puberty, children with McCune-Albright may stop growing early and may be shorter than their peers. This might cause social difficulties for them. However, early interventions and treatments can help postpone these changes and prevent puberty from occurring too soon.

McCune-Albright is a rare genetic condition that leads to bone, skin, and hormonal symptoms. Medical professionals typically diagnose this condition in early childhood.

Some people experience mild symptoms, while other people experience severe symptoms. The symptoms can include bone scarring that leads to:

  • easy fracturing
  • bone pain
  • uneven bone growth
  • early puberty
  • an enlarged thyroid
  • Cushing syndrome
  • café au lait spots

There is currently no cure for McCune-Albright syndrome, but the condition usually doesn’t affect life expectancy. People can generally manage symptoms with medications, physical and occupational therapy, and surgery.