My Orthopaedic Surgeon

Abstract The etiology of slipped capital femoral epiphysis is still unknown. Traumatic, endocrine, toxic, and mechanical causes have all been hypothesized. It is well documented that the highest incidence occurs during the adolescent growth spurt, suggesting the role of an endocrine abnormality. We report a case that supports this hypothesis Skeletal Radiology Volume 26, Number 3 / March, 1997 Authors A. Feydy, R. Y. Carlier, D. Mompoint, G. Rougereau, A. Patel, C. Vallée

This condition was first described by McCune and Albright in 1936 and 1937 respectively. They described the classic triad of irregular skin pigmentation, bony abnormalities, and sexual precocity. DrGreene

Author: Gabriel I Uwaifo, MBBS, Clinical and Research Attending, MedStar Clinical Research Center, Assistant Professor of Medicine and Endocrinology, The MedStar Research Institute and the Washington Hospital Center Coauthor(s): Nicholas J Sarlis, MBBS, MD, PhD, FACP, Medical Director, Department of Oncology-US Medical Affairs Department, Sanofi-Aventis Pharmaceuticals Background McCune-Albright syndrome (MAS) is defined as the association of polyostotic fibrous dysplasia (PFD) (see Image 1), precocious puberty, café au lait spots, and other endocrinopathies due to hyperactivity of various endocrine glands. Fuller Albright first described this syndrome in 1937. The first case described by Donovan McCune had the classic triad and hyperthyroidism. Other cases have been retrospectively identified since antiquity, such as the Tegernsee Giant, who probably had MAS and acromegaly. MAS has been shown to be due to a postzygotic activating mutation of the GS alpha gene in the affected tissues. For semantic reasons, differentiating MAS and Albright hereditary osteodystrophy (AHO) is important. AHO also is a GS alpha gene defect that results in pseudohypoparathyroidism or pseudopseudohypoparathyroidism. The precocious puberty associated with MAS typically is gonadotrophin-independent. Among the endocrine syndromes described in association with MAS are (1) hyperthyroidism, (2) acromegaly, (3) gonadotrophinomas, (4) hyperprolactinemia, (5) Cushing syndrome, (6) hyperparathyroidism, (7) gynecomastia, and (8) hypophosphatemic rickets. Some severely affected patients may present with associated hepatic, cardiac, and GI dysfunction (ie, elevated hepatic transaminases, GI polyposis, and cardiomyopathy).

Alternative titles; symbols ALBRIGHT SYNDROME POLYOSTOTIC FIBROUS DYSPLASIA; PFD; POFD this phenotype is associated with mutations in the GNAS1 gene (139320). The McCune-Albright syndrome, usually caused by mosaicism for a mutation in the GNAS1 gene, is characterized by polyostotic fibrous dysplasia, pigment patches of the skin and endocrinologic abnormalities, including precocious puberty, thyrotoxicosis, pituitary gigantism, and Cushing syndrome (219080). CLINICAL FEATURES This disorder is called McCune-Albright syndrome or simply Albright syndrome, but should not be confused with Albright hereditary osteodystrophy, or pseudohypoparathyroidism (103580). The predominant features of the syndrome occur in 3 areas: the bony skeleton, the skin, and the endocrine system. In all 3 systems, the extent of the abnormality and, in the case of the endocrine system, the nature of the abnormality, are highly variable from case to case, depending on the specific tissues involved in the mosaicism and the extent of involvement. Skeletal No bone is spared. There is a strong tendency to asymmetry. Involvement of the skull and facial bones can be striking, and in the case of these bones also, asymmetry is the rule. Pathologic fracture or bone deformity may be presenting manifestations and pseudarthrosis occurs frequently. Deafness and blindness can result from impingement of the bony process on the cranial foramina. Shepherd's crook deformity of the proximal femur is particularly characteristic of the bony involvement. (The bone lesions of neurofibromatosis are usually less extensive than are those in polyostotic fibrous dysplasia, but may be difficult to distinguish on radiologic grounds alone.) Hypophosphatemic osteomalacia ('rickets') has been observed in some cases of polyostotic fibrous dysplasia. Dent and Gertner (1976) suggested that this may represent a situation comparable to 'tumor rickets' which is associated with mesenchymal tumors and regresses when the tumor is removed. McArthur et al. (1979) described 4 patients with Albright syndrome, hypophosphatemia, and inappropriately low renal tubular reabsorption of phosphate. Three of the patients had radiologic evidence of rickets. They postulated that a substance elaborated by the dysplastic bone interfered with phosphate reabsorption in the renal tubule.

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

acromegaly