Abstract
McCune-Albright syndrome (MAS) is a rare, sporadic mosaic disorder classically characterized by fibrous dysplasia (FD) of bone, café-au-lait macules, and endocrine hyperfunction. The estimated prevalence ranges from 1 in 100,000 to 1 in 1,000,000 individuals, with no clear differences across ethnic groups. The central pathogenic mechanism involves postzygotic somatic gain-of-function mutations in the GNAS gene, which encodes the α subunit of the stimulatory G protein (Gsα). The currently identified pathogenic variants are concentrated at codons R201 (e.g., R201H and R201C) and Q227. This review systematically summarizes the molecular genetic basis, phenotypic heterogeneity, histopathological and imaging characteristics, diagnostic strategies, precision treatment approaches, and long-term prognosis of MAS. By integrating recent advances, we also highlight emerging research directions and provide a structured framework to support clinical diagnosis and multidisciplinary management.