TTR and Alzheimer disease: In addition to its role as a transporter of thyroid hormone in the brain, Ttr has also been demonstrated to have other functions, including neuroprotective effects in hippocampal neurons and pathological conditions such as brain ischemia (Gomes et al., 2016; Santos et al., 2010) and AD (Buxbaum et al., 2008; Oliveira et al., 2011; Silva et al., 2017).