McCune-Albright syndrome

Definition

• Early fetal mutation resulting in a syndrome consisting of fibrous bone dysplasia, cafe-au-lait spots, and hyperfunctioning endocrinopathies, including precocious puberty, hyperthyroidism, growth hormone excess, Cushing syndrome, and renal phosphate wasting

Etiology

• Gain-of-function mutation of the GNAS gene early in fetal development

Epidemiology

• 1 in 100,000 to 1 in 1,000,000

Management

• Surveillance
  • CT head to follow craniofacial dysplasia
  • Gonadal ultrasound q1yr to follow testicular lesions
  • Thyroid ultrasound q1yr to follow thyroid lesions
• Symptomatic treatment
  • Fibrous dysplasia: bisphosphonates improve pain
  • Precocious puberty
  • Growth hormone excess: octreotide or pegvisomant or surgery (but very difficult given craniofacial dysplasia)
  • Hyperthyroidism: irradiation or surgery