A 25-year-old woman has diffuse goiter, proptosis, heat intolerance, and tremor. Serum TSH is suppressed and free T4 is elevated. The antibody responsible for initiating this disorder is directed against which target?

• A Thyroid peroxidase
• B Sodium iodide symporter
• C Thyroglobulin
• D TSH receptor ✓

Explanation

Graves disease is caused by autoantibodies against the TSH receptor that act as agonists, stimulating hormone synthesis and glandular growth, producing diffuse goiter and hyperthyroidism. Anti-TPO and anti-thyroglobulin antibodies are markers of Hashimoto thyroiditis and may be present in Graves but do not drive it. Antibodies to the sodium iodide symporter are not the primary pathogenic mechanism in standard texts.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.