August 11, 2026, 8:19 am | Read time: 4 minutes
McCune-Albright syndrome (MAS) is an extremely rare genetic disorder, so rare that many doctors never encounter it throughout their careers. In young children, early puberty can occur, noticeable skin spots may develop, and bone growth can change. FITBOOK explains the causes, symptoms, and treatment framework.
How Rare is the Disease and What Causes It?
The name of the syndrome might not be entirely unfamiliar to you. After Josefine Scholl, daughter of former soccer professional Mehmet Scholl, publicly disclosed her condition in 2026, McCune-Albright syndrome received significant media attention. Otherwise, the syndrome garners little attention, partly due to its rarity. Its prevalence is estimated at about 1 in 100,000 to 1 in 1,000,000. Additionally, it is not a classic hereditary disease. The underlying genetic mutation occurs randomly in an early phase of embryonic development and is generally not passed from parents to children. Parents have no influence on its occurrence. Notably, the syndrome is diagnosed much more frequently in girls than in boys. For every boy, there are about two to six girls. However, this difference may be partly because typical symptoms like early puberty are more easily recognized in girls.
The disease was first described by its two namesakes: American pediatrician Donovan James McCune in 1936 and American endocrinologist Fuller Albright in 1937.
Symptoms of McCune-Albright Syndrome
Although the genetic mutation occurs very early after fertilization in the womb, the disease usually goes unnoticed at birth. The first symptoms appear in infancy and early childhood. However, some affected individuals show only a few symptoms or develop them later in life, which can complicate diagnosis. Life expectancy is generally not or only slightly affected for many patients. Typical symptoms include:
- noticeable skin spots
- unusual bone growth
- unusually early puberty
Unusual Bone Growth
Unusual bone growth is one of the three typical features of McCune-Albright syndrome. Healthy bone tissue is partially replaced by softer connective tissue. Doctors refer to this as fibrous dysplasia. Affected areas can include the skull, ribs, pelvis, thighs, or upper arms. These changes can lead to bone pain, bone deformities, and an increased risk of fractures. Depending on which bones are affected, facial asymmetries, leg length differences, or spinal curvature may also occur.
As a patient, Josefine Scholl describes her bone-related suffering on as follows: “I actually have pain every day, so I grew up with it. I have pain in my upper arm but also generally on my right side.”
The Noticeable Skin Spots
Named for their coffee-like color, these skin changes are called café-au-lait spots. They are light to dark brown pigment spots that can also appear in early childhood. They are among the typical features of McCune-Albright syndrome, although their presence alone is not sufficient for diagnosis, as they can occur in other conditions as well. Typical for the syndrome, however, is that the spots often appear on one side and have irregular, jagged edges. They are usually found on the torso, back, or neck.
The Unusually Early Puberty
As mentioned earlier, the syndrome is more frequently diagnosed in girls than in boys, primarily because early puberty is more easily recognized in girls. Vaginal bleeding and breast development can occur in childhood. A case report of a girl who experienced vaginal bleeding at just 17 months old illustrates how early these symptoms can manifest. However, boys can also show signs of early puberty, such as enlarged testicles, the appearance of pubic or body hair, and accelerated growth. These signs, however, often go unnoticed for longer.
Possible Secondary Conditions
Depending on its severity, the syndrome can lead to various secondary conditions. Recurrent bone fractures, bone misalignments, or spinal curvature due to fibrous dysplasia are typical consequences. Other hormonal disorders, such as hyperthyroidism, can also occur. The effects of the disease, however, vary significantly from person to person.
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Diagnosis
The diagnosis is made through a series of examinations. Multiple tests are necessary, including physical exams, blood tests to determine hormone levels, imaging procedures like X-rays, and genetic tests of skin or tissue samples.
Curability
McCune-Albright syndrome is currently incurable. However, individual symptoms and secondary conditions can be specifically treated. The choice of therapy depends on which organs are affected and which symptoms occur. The goal of treatment is to alleviate symptoms, prevent complications, and improve the quality of life for those affected.