The Thr92AlaD2 Polymorphism May Play a Novel Role in Hypothyroidism

Abstract

The type 2 deiodinase (D2) has an important role in hypothyroidism, where its ability to activate thyroid hormone provides justification for levothyroxine “monotherapy.” A prevalent polymorphism in D2, Thr92AlaD2, has been associated with improved well-being on “combination therapy” with T4+T3; the underlying mechanism is unclear as T4-to-T3 conversion appears normal. Novel studies indicate this might be a risk factor for neurodegenerative disease. If the relationship between Thr92AlaD2-expression and treatment preference is confirmed, personalized medicine may play a role in hypothyroidism.