Figure 6From: McCune-Albright syndromeMolecular and developmental defect in McCune-Albright syndrome (MAS). A sporadic mutation occurs in a single cell (bright spot) at some point early in development. If this occurs at the inner call mass stage (embryonic stem cell stage), tissues from all 3 germ layers will be affected. As the cells derived from this mutated clone are dispersed throughout the organism, the final phenotype emerges, MAS.Back to article page