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McCune-Albright syndrome is a sporadic disease characterized by polyostotic fibrous dysplasia, café-aux-lait lesions, and a variety of endocrine disorders (1, 2). The molecular basis of this syndrome has recently been elucidated. Missense point mutations in the GNAS1 gene located on the long arm of chromosome 20 and encoding for the α subunit of Gs (the G protein that stimulates cAMP) of transmembrane glycoprotein receptors have been identified (3, 4). Mutations at codon 201 substituting Arg with either Cys or His give rise to abnormal Gsα proteins that reduce the intrinsic guanosine triphosphatase activity, thereby constitutively activating the Gs protein. The mutation is found in variable abundance in different endocrine and nonendocrine tissues, consistent with the mosaic distribution of abnormal cells generated by a somatic cell mutation early in embryogenesis. Severe disease may be associated with an earlier mutational event leading to more widespread distribution of mutated cells (5).

The most commonly encountered endocrine dysfunction in McCune-Albright syndrome is gonadal hyperfunction. Precocious puberty represents the usual initial manifestation of McCune-Albright syndrome in girls. Ovarian cysts may be found on pelvic ultrasound (6–8). Other endocrine abnormalities include hyperfunction of the thyroid and adrenal cortex, as well as excessive GH secretion. The majority of patients have abnormally elevated sex steroids with low or undetectable gonadotropin levels (5). Whereas pregnancies have been described later in life (9, 10), polymenorrhea and amenorrhea due to continued gonadotropin-independent estrogen production have also been reported (11). However, clinical information regarding ovarian dysfunction in McCune-Albright patients during adolescent and adult life is scant.

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