McCune-Albright syndrome

McCune-Albright syndrome is a rare condition combining fibrous dysplasia (abnormal, weakened bone tissue), café-au-lait skin patches, and hormonal disorders including early puberty. It results from a genetic mutation that occurs after conception, meaning it isn't inherited in the traditional sense.

It's caused by a mutation in the GNAS gene occurring very early in development, affecting only some of the body's cells (a mosaic pattern), which explains why features and severity vary so much between affected individuals depending on which tissues are affected. This mutation arises spontaneously rather than being inherited from a parent.

Symptoms include bone pain, fractures, and deformity from fibrous dysplasia, distinctive irregular-bordered café-au-lait skin patches, and hormonal problems including early puberty, and sometimes other endocrine gland overactivity. The specific combination and severity of features varies considerably between affected individuals.

It can cause significant bone fragility and deformity, and hormonal complications need careful management, but with appropriate multidisciplinary care, many people manage the condition well throughout life. Regular monitoring for the various possible complications is important given the range of body systems that can be affected.

It results from a genetic mutation, but this occurs spontaneously after conception rather than being inherited from a parent, meaning it's essentially never passed on to children. This mosaic pattern of mutation, affecting only some cells, also explains the varied features between different affected individuals.

There's no cure for the underlying genetic mosaic pattern, but individual features such as bone problems and hormonal disorders can be actively managed with appropriate specific treatment. A multidisciplinary specialist team approach, given the range of possible affected systems, gives the best outcomes.

Treatment includes bone-strengthening medication and orthopaedic management for fibrous dysplasia, and specific hormonal treatment for issues such as early puberty or other endocrine gland overactivity. Regular monitoring across affected systems helps guide ongoing, tailored management.

Diagnosis is typically based on the characteristic combination of clinical features, sometimes supported by imaging showing fibrous dysplasia and specific genetic testing for the GNAS mutation, though this genetic testing can be technically challenging given the mosaic nature of the mutation. A specialist familiar with this rare condition can guide appropriate diagnostic assessment.

No, given the mosaic nature of the underlying mutation, some people have only one or two of the classic features (bone, skin, hormonal), while others have the full combination, and severity varies considerably. This variability is a recognised feature of the condition, related to which specific tissues are affected by the mutation.

The combination of bone pain or deformity, characteristic skin patches, or signs of early puberty should prompt specialist paediatric endocrinology and genetics assessment. Private specialist consultations can typically be arranged within about two weeks, considerably faster than standard NHS waiting times.