McCune-Albright syndrome (MAS) is a rare, genetic, non-inherited condition that causes bone tumors, bone deformity and fractures. The manifestations include polyostotic fibrous dysplasia, café au lait spots, and precocious puberty.Mutation of the GS gene in chromosome 20q13 occurs early in development, and results in a mosaic of abnormal and mutated cells. The manifestations of MAS in each individual depend upon the extent and distribution of abnormal cells. Abnormal and prolonged activation of multiple peripheral endocrine glands occurs even while the necessary stimulatory pituitary hormones may be absent. Precocious puberty, with onset of breast development, pubic hair, and the onset of menses as early as the first few months of life may occur in females. Other manifestations include acromegaly, hyperthyroidism, hyperprolactinemia, and others. Frequently involved bones include the femur, the tibia, the facial skeleton, and the ribs. Bone fragility and associated fractures are common, and weight-bearing bones may suffer multiple fractures. In the proximal femurs, multiple successive cortical microfractures may result in characteristic bowing of the proximal end of the bone into a "shepherd's crook" deformity. Scholarly peer review is the process of subjecting an author's scholarly work, research, or ideas to the scrutiny of others who are experts in the same field, before a paper describing this work is published in a journal. The work may be accepted, considered acceptable with revisions, or rejected. Peer review requires a community of experts in a given (narrowly defined) field, who are qualified and able to perform reasonably impartial review.