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Localized Hypothyroidism

Meaning

Localized Hypothyroidism describes a functional state where specific organs or tissues within the body experience an insufficient concentration of the active thyroid hormone, Triiodothyronine (T3), even though standard systemic blood tests show thyroid hormone levels within the normal population reference range. This cellular-level T3 deficit is frequently caused by impaired local T4-to-T3 conversion or compromised T3 transport into target cells, particularly affecting tissues with high Deiodinase D2 activity such as the brain and skeletal muscle. It is considered a functional, tissue-specific thyroid deficiency, rather than a systemic one.