We hypothesise that there are multiple factors that are likely to have contributed to this observation: (1) In peripheral blood, 80–90% of T3 is converted from T4 by deiodinase, and the clinical stress of stroke inhibits this deiodinase conversion and thereby reduces levels of T3, which is the main thyroid hormone that exerts a wide range of biological effects, including effects on the nervous system (Bunevicius et al., 2016; Chen et al., 2016; Lamba et al., 2018; Wang et al., 2017). The gene discussed is TG; the disease is Stroke.