If a patient has a genetic mutation causing a constitutively active (always on) thyroid stimulating hormone (TSH) receptor in thyroid follicular cells, which consequence follows?

💡 Explanation

The constitutively active TSH receptor continuously stimulates thyroid follicular cells, causing increased thyroid hormone (T3 and T4) production and release. This leads to hyperthyroidism, even when circulating TSH is low, because the thyroid is autonomously activated, therefore the correct answer is C rather than A, B, or D.

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