McCune-Albright syndrome is a rare genetic disorder that affects bone, skin, and hormone production. It is caused by a mutation in the GNAS gene, which leads to abnormal cell growth and function. Individuals with this syndrome often experience fibrous dysplasia, where normal bone is replaced with fibrous tissue, resulting in weak bones and deformities. In addition to bone issues, people with McCune-Albright syndrome may develop skin pigmentation changes, such as café-au-lait spots, and experience hormonal imbalances. These hormonal changes can lead to early puberty in girls and other endocrine disorders. The symptoms and severity can vary widely among affected individuals.