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$Unique_ID{BRK03979}
$Pretitle{}
$Title{McCune-Albright Syndrome}
$Subject{McCune-Albright Syndrome Albright Syndrome Polyostotic, Fibrous
Dysplasia Osteitis Fibrosa Disseminata Neurofibromatosis Type I Von
Recklinghausen Disease Peripheral Neurofibromatosis}
$Volume{}
$Log{}
Copyright (C) 1986, 1987, 1988, 1989, 1991, 1992 National Organization
for Rare Disorders, Inc.
183:
McCune-Albright Syndrome
** IMPORTANT **
It is possible the main title of the article (McCune-Albright Syndrome)
is not the name you expected. Please check the SYNONYMS listing on the next
page to find alternate names, disorder subdivisions, and related disorders
covered by this article.
Synonyms
Albright Syndrome
Polyostotic, Fibrous Dysplasia
Osteitis Fibrosa Disseminata
Information on the following disease can be found in the Related
Disorders section of this report:
Neurofibromatosis, Type I (Von Recklinghausen Disease or Peripheral
Neurofibromatosis)
General Discussion
** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only. It should not be used for diagnostic or treatment
purposes. If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.
McCune-Albright Syndrome is a multi-system disorder primarily
characterized by abnormal fibrous tissue development (dysplasia) in one or
more bones, abnormally early puberty, and brown (cafe-au-lait) spots on the
skin. Other symptoms may include an overactive thyroid gland
(hyperthyroidism), other endocrine abnormalities, and a variety of bone and
soft-tissue tumors.
Symptoms
Individuals with McCune-Albright Syndrome are affected by abnormal fibrous
bone tissue growth which may be progressively painful and disabling. These
lesions may affect any bone in the body, but most frequently are found in the
arms, legs, pelvis, fingers or toes, as well as the ribs and the base of the
skull. Susceptibility to fractures, shortening of the limbs, and other bone
deformities may occur.
Skin abnormalities consist of large brown (cafe-au-lait) spots which tend
to have an irregular contour. These spots do not appear in every case of
McCune-Albright Syndrome, thus are not necessary for a diagnosis.
Early or "precocious" puberty manifests itself more often among female
than among male patients. The premature onset of puberty may occur as early
as three months of age. In females, the monthly menstrual period occurs
followed years later by the development of breasts and growth of axillary
hair. Fertility among young patients is very rare, but has been found.
Fertility among adults with McCune-Albright Syndrome appears to be normal.
Enlargement of the nose, jaw, fingers and toes (acromegaly) may result
from an excess of growth hormone secreted by the pituitary gland and possibly
excessive growth (gigantism) during childhood. However, growth may stop at
an early age, leaving the patient at a shorter height than normal adults.
(For more information on this disorder, choose "acromegaly" as your search
term in the Rare Disease Database.)
Causes
The exact cause of McCune-Albright Syndrome is not known. Most cases seem to
occur sporadically. Although scientists suspect the disorder may be
inherited, this has not yet been proven. The early (false or
pseudoprecocious) puberty in females with McCune-Albright may be linked to
increased ovarian function caused by increased thyroid gland function
(hyperthyroidism), hypercortisolism, excessive growth hormone and
hypophaasphatemia or premature activation of the hypothalamic-pituitary-
ovarian axis. Scientists believe that in many cases McCune-Albright Syndrome
is caused by a mutation of the Gsx gene in early development.
Affected Population
McCune-Albright Syndrome can affect both sexes. Early or pseudoprecocious
puberty occurs in approximately thirty percent of patients, most often among
affected females. Since this disorder was first identified by Albright in
1937, hundreds of cases have been described in the American medical
literature.
Related Disorders
Symptoms of the following disorder can be similar to those of McCune-Albright
Syndrome. Comparisons may be useful for a differential diagnosis:
Neurofibromatosis (NF), Type I, also known as Von Recklinghausen's
Disease or Peripheral Neurofibromatosis, is characterized by multiple brown
(cafe-au-lait) colored spots on the skin, nerve tumors of varying sizes under
the skin, and curvature of the spine or other bones. Disturbances of puberty
may also occur. This disorder is inherited as an autosomal dominant trait,
whereas the exact cause of McCune-Albright Syndrome is not known. The
discolorations of the skin found in Neurofibromatosis I patients are
different from those found in McCune-Albright Syndrome patients. (For more
information on this disorder, choose "NF" as your search term in the Rare
Disease Database).
Therapies: Standard
Treatment of McCune-Albright Syndrome is symptomatic and supportive. In some
severe cases, surgical removal of the thyroid gland may improve persistent
increased thyroid function (hyperthyroidism). In other cases, physicians may
try to delay puberty through use of hormones. Bone fractures and orthopedic
problems are treated by orthopedists.
Therapies: Investigational
Experimental treatment for premature puberty in females with McCune-Albright
Syndrome consists of a trial of the aromatase inhibitor testolactone, which
blocks the synthesis of estrogens. More research is required before this
therapy can be recommended as a safe and effective therapy for this disorder.
Cortical bone grafting has been investigated as a possible treatment for
fibrous bone tissue development (fibrous dysplasia), especially when a
fracture has occurred. The objective of this experimental procedure is to
attain pain relief, union of the fracture, and prevention of deformity.
Again, more research is necessary before benefits can be adequately assessed.
Investigators in the Reproductive Endocrine Unit at Massachusetts General
Hospital are currently studying more about the reproductive function in
teenage and adult females with McCune-Albright Syndrome. Interested females
will be sent a questionnaire. Patients or parents of patients wishing to
learn more about this study can contact:
Dr. Lauren S. Frisch
Reproductive Endocrine Unit
Bartlett Hall Ext., 5th Floor
Massachusetts General Hospital
Fruit Street
Boston, MA 02114
(617) 726-8433, ext. 337
This disease entry is based upon medical information available through
January 1992. Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.
Resources
For more information on McCune-Albright syndrome, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
McCune-Albright Syndrome Division of the MAGIC Foundation
30 Beloak Ct.
Baltimore, MD 21236
(301) 529-0653
The National Arthritis and Musculoskeletal and Skin Diseases Information
Clearinghouse
Box AMS
Bethesda, MD 20892
(301) 495-4484
International Center for Skeletal Dysplasia
St. Joseph Hospital
7620 York Road
Towson, MD 21204
(301) 337-1250
For genetic information and genetic counseling referrals, please contact:
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
(914) 428-7100
Alliance of Genetic Support Groups
35 Wisconsin Circle, Suite 440
Chevy Chase, MD 20815
(800) 336-GENE
(301) 652-5553
References
TREATMENT OF PRECOCIOUS PUBERTY IN THE MCCUNE-ALBRIGHT SYNDROME WITH
THEAROMATASE INHIBITOR TESTOLACTONE: J.D. Malley, et al.; N Eng J Med
(October 30, 1986, issue 315 (18)). Pp. 1115-1119.
NEUROFIBROMATOSIS AND ALBRIGHT'S SYNDROME: V.M. Riccardi; Dermatol Clin
(January 1987, issue 5 (1)). Pp. 193-203.
FIBROUS DYSPLASIA OF THE FEMORAL NECK. TREATMENT BY CORTICAL BONE-GRAFTING:
W.F. Enneking, et al.; J Bone Joint Surg [AM] (December 1986, issue 68(9)).
Pp. 1415-1422.
ACTIVATING MUTATIONS OF THE STIMULATORY G PROTEIN IN THE MCCUNE-ALBRIGHT
SYNDROME, Weinstein, L.S., et al.; N Eng J Med, December 12, 1991 (issue 325
(24)). Pp. 1688-1695.
THE MCCUNE-ALBRIGHT SYNDROME, THE WHYS AND WHEREFORES OF ABNORMAL SIGNAL
TRANSDUCTION, (editorial) Levine, Michael A., New Eng J of Med., December 12,
1991 (issue 325 (24)). Pp. 1738-1740.