Fibrous Dysplasia of Bone and McCune–Albright Syndrome: A Bench to Bedside Review

Fibrous dysplasia is an uncommon mosaic disorder in which bone is replaced by structurally unsound fibro-osseous tissue. It is caused by the sporadic post-zygotic activating mutations in GNAS , resulting in dysregulated Gα S -protein signaling in affected tissues. This manifests on a broad clinical spectrum ranging from insignificant solitary lesions to severe disease with deformities, fractures, functional impairment, and pain. Fibrous dysplasia may present in isolation or in association with hyperfunctioning endocrinopathies and café-au-lait macules, known as McCune–Albright Syndrome. This review summarizes the current understanding of pathophysiology in fibrous dysplasia, describes key pre-clinical and clinical investigations, and details the current approach to diagnosis and management.