A 33-year-old woman came to a dentist complaining of an aesthetic defect in her teeth 11 and 21 and a short-term pain that occurs when she eats sour or sweet foods. Objectively, the vestibular surface of teeth 11 and 21 have defects of hard tissues within the dentinoenamel junction. The defects have gently sloping walls and a dense floor and are painful to probing. The skin of the face, the vermilion border of the lips, and oral mucosa have no visible pathological changes. The woman additionally complains of sweating. tachycardia, and increased appetite. She is thin and has exophthalmos. What has caused the development of this pathology?