McCune-Albright Syndrome

Not Verified
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Disease overview

Sporadic variant (typically mosaic pattern) in GNAS1 gene causing constitutive activation of Gs-coupled receptors and excess cAMP production (leading to excess hormone production), affecting the bones, skin, and endocrine system. ]

Common symptoms

Highly variable presentation due to mosaic pattern of variant. Bone: polyostotic fibrous dysplasiausually in long bones or craniofacial bones and asymmetricincreased fracture risk. Skin: cafe-au-lait spots ("Coast of Maine")usually unilateral. Endocrine: precocious puberty ( common in girls)hyperthyroidismgrowth hormone excessCushing syndrome.

WHEN TO SUSPECT

  • Recommendation 1

    Multiple cafe-au-lait spots at birth should prompt workup

  • Recommendation 2

    many patients are not diagnosed until precocious puberty or bone deformity forms. 2 or more of the following constitute a diagnosis

  • Recommendation 3

    fibrous dysplasia of bone, cafe-au-lait spots, precocious puberty, testicular lesions, thyroid lesions, GH excess, neonatal hypercortisolism. Blood tests to measure sex hormones, thyroid hormone, pituitary hormones, and cortisol should be collected

  • Recommendation 4

    bone scintigraphy can be used to assess for extent of osseous disease. Definitive diagnosis can be made with PCR testing, but given mosaic nature of disease a single negative test does not rule out the disease.

HOW TO TEST

  • Recommendation 1

    Multiple cafe-au-lait spots at birth should prompt workup

  • Recommendation 2

    many patients are not diagnosed until precocious puberty or bone deformity forms. 2 or more of the following constitute a diagnosis

  • Recommendation 3

    fibrous dysplasia of bone, cafe-au-lait spots, precocious puberty, testicular lesions, thyroid lesions, GH excess, neonatal hypercortisolism. Blood tests to measure sex hormones, thyroid hormone, pituitary hormones, and cortisol should be collected

  • Recommendation 4

    bone scintigraphy can be used to assess for extent of osseous disease. Definitive diagnosis can be made with PCR testing, but given mosaic nature of disease a single negative test does not rule out the disease.

TREATMENT

  • Recommendation 1

    Treatment is largely symptomatic as-needed. Skeletal dysplasia may require corrective surgery

  • Recommendation 2

    patients may benefit from vitamin D and phosphorus supplements. Precocious puberty can be delayed with letrozole or other aromatase inhibitor (gonadotropin therapy usually does not work). Somatostatin analogs can be used for GH excess. Patients may need standard treatment for hyperthyroidism, Cushing syndrome.

PRIMARY CARE

  • Recommendation 1

    Routine monitoring for and treatment of symptoms as applicable. Patients commonly experience pain and disability and will benefit from psychosocial support.

FURTHER SUPPORT

  • Recommendation 1

    Patients may require visits with a variety of specialists including orthopedics, endocrinology, pain management, craniofacial surgery, and others. The FD/MAS Alliance maintains a physician database of providers in various specialties with experience treating MAS.Referral to Medical Genetics Department, if available. Initial virtual care is also available through organizations like TeleRare Health.

CLINICAL TRIALS

  • Recommendation 1

    Areas of future study include estrogen receptor antagonists, denosumab, and tocilizumab for symptom control. . A few trials in the US and internationally are recruiting.

Sources

No data available

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