A 32-year-old woman comes to the office due to recent fatigue and weight gain. She has no medical histrory and takes no medication. Blood pressure is 115/65 mm Hg and pulse is 85/min. On physical examination, there is a diffuse neck swelling with no palpable nodules, she says her neck has gradually gotten larger, and she does not like how it appears in the mirror. Serum TSH and free thyroxine levels are normal. She has a sister with vitiligo. There is no history of head and neck irradiation. Antibodies against thyroid peroxidase are present in high titers. The antigenic target of these antibodies is involved in which of the following processes?

Question

A 32-year-old woman comes to the office due to recent fatigue and weight gain. She has no medical histrory and takes no medication. Blood pressure is 115/65 mm Hg and pulse is 85/min. On physical examination, there is a diffuse neck swelling with no palpable nodules, she says her neck has gradually gotten larger, and she does not like how it appears in the mirror. Serum TSH and free thyroxine levels are normal. She has a sister with vitiligo.  There is no history of head and neck irradiation.  Antibodies against thyroid peroxidase are present in high titers.  The antigenic target of these antibodies is involved in which of the following processes?

Quizplus · Accepted Answer

Eductional Objective: Thyroid peroxidase (TPO) catalyzes the oxidation of iodide to iodine, the iodination of thyroglobulin tyrosine residues, and the iodotyrosine coupling reaction that forms T3 and T4.  Antibodies against TPO are present in >90% of patients with chronic lymphocytic (Hashimoto) thyroiditis.

A 32-Year-Old Woman Comes to the Office Due to Recent