Polyostotic fibrous dysplasia DefinitionMcCune-Albright syndrome is a genetic disease that affects the bones, hormones, and color (pigmentation) of the skin. CausesMcCune-Albright syndrome is caused by mutations in the GNAS gene. A small number, but not all, of the person's cells contain this faulty gene (mosaicism). This disease is not inherited. SymptomsThe main symptom of McCune-Albright syndrome is early puberty in girls. Menstrual periods may begin in early childhood, long before the breasts or pubic hair develop (which normally occur first). The average age that symptoms appear is 3 years old. However, puberty and menstrual bleeding have occurred as early as 4 to 6 months in girls. Early sexual development may also occur in boys, but not as often as in girls. Other symptoms include:
Exams and TestsA physical examination may show signs of:
Tests may show:
Other tests that may be done include:
Genetic testing may be done to confirm the diagnosis. TreatmentThere is no specific treatment for McCune-Albright syndrome. Drugs that block estrogen production, such as testolactone, have been tried with some success. Adrenal abnormalities (such as Cushing syndrome) may be treated with surgery to remove the adrenal glands. Gigantism and pituitary adenoma will need to be treated with medicines that block hormone production, or with surgery. Bone abnormalities (fibrous dysplasia) are sometimes removed with surgery. Limit the number of x-rays taken of affected areas of the body. Outlook (Prognosis)Lifespan is relatively normal. Possible ComplicationsComplications may include:
When to Contact a Medical ProfessionalContact your health care provider if your child starts puberty early, or has other symptoms of McCune-Albright syndrome. Genetic counseling, and possibly genetic testing, may be suggested if the disease is detected. ReferencesGaribaldi LR, Chemaitilly W. Disorders of pubertal development. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 578. Styne DM. Physiology and disorders of puberty. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 26. | |
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Review Date: 7/26/2022 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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