Multiple endocrine neoplasia syndromesDownloads

A 27-year-old man comes to the physician because of worsening abdominal pain over the last several months. He has also had recent feelings of sadness and a lack of motivation at work, where he is employed as a computer programmer. He denies suicidal thoughts. He has a history of multiple kidney stones. He has a family history of thyroid cancer in his father and uncle, who both underwent thyroidectomy before age 30. His temperature is 37°C (98°F), blood pressure is 138/86 mm Hg, and pulse is 87/min. Physical examination shows diffuse tenderness over the abdomen and obesity but is otherwise unremarkable. Serum studies show: Na+ 141 mEq/L K+ 3.6 mEq/L Glucose 144 mg/dL Ca2+ 12.1 mg/dL Albumin 4.1 g/dL PTH 226 pg/mL (normal range 12–88 pg/mL) Results of a RET gene test return abnormal. The physician refers him to an endocrine surgeon. Which of the following is the most appropriate next step in diagnosis?

A 16-year-old boy is brought to the emergency department after losing consciousness. He had no preceding chest pain or palpitations. His father has cataracts and had frontal balding in his twenties but has no history of cardiac disease. His paternal grandfather also had early-onset balding. His pulse is 43/min. Physical examination shows frontal hair loss, temporal muscle wasting, and testicular atrophy. Neurologic examination shows bilateral foot drop and weakness of the intrinsic hand muscles. An ECG shows bradycardia with third-degree atrioventricular block. The severity of this patient's symptoms compared to that of his father is most likely due to which of the following genetic properties?