McCune Albright Syndrome WebMD

Description: Synonyms MAS Albright Syndrome Osteitis Fibrosa Disseminata Polyostotic, Fibrous Dysplasia PFD Precocious Puberty with Polyostotic Fibrosis and Abnormal Pigmentation POFD General Discussion McCune-Albright Syndrome (MAS) is a rare multisystem disorder characterized by (1) replacement of normal bone tissue with areas of abnormal fibrous growth (fibrous dysplasia); (2) patches of abnormal skin pigmentation (i.e., areas of light-brown skin [cafe-au-lait spots] with jagged borders); abnormalities in the glands that regulate the body’s rate of growth, its sexual development, and certain other metabolic functions (multiple endocrine dysfunction). Depending on the number and location of the skeletal abnormalities, mobility may be impaired, as well as vision and/or hearing, and the individual may experience substantial pain. Malfunctioning endocrine glands can result in the development of secondary sexual characteristics at an age younger than normal (precocious puberty). McCune-Albright Syndrome is the result of a genetic change (mutation) that occurs randomly, for no apparent reason (sporadic). In individuals with the disorder, this sporadic genetic mutation is present in only some of the body's cells (mosaic pattern). The symptoms and physical characteristics associated with the disorder vary greatly from case to case, depending upon the specific body cells and tissues that are affected by the genetic mutation. This mutation occurs after fertilization (postzygotic somatic mutation). It is not inherited from the parents. The range of severity of the disorder is very broad: some children are diagnosed in early infancy with obvious anomalies of bone and increased hormone production by one or more of the endocrine glands; others show no evidence of bone, skin or endocrine malfunction in childhood and may enter puberty at an appropriate age. Information from NORD