Symptoms:

• Irregular, patchy cafe-au-lait spots, especially on the back
• Vaginal bleeding (first menstruation) at a very early age
• Premature puberty
  • early breast development
  • early pubic and armpit hair development
• Some patients get more broken bones
• Rarely, a form of gigantism (overgrowth of the body caused by excess hormones)

Signs and tests:

A physical examination may show signs of:

• Hyperthyroidism (occasionally)
• Adrenal abnormalities (occasionally)
• Acromegaly (occasionally)
• Cafe-au-lait spots of the skin

Tests may show signs of hyperthyroidism, hyperparathyroidism, excess adrenal hormones, or excess blood prolactin or growth hormone.

X-rays show fibrous dysplasia that affects multiple bones. An MRI of the head may show a type of tumor called an adenoma in the pituitary gland. Genetic testing may be available for the GNAS1 gene.