Wild-type transthyretin amyloidosis (ATTRwt) is an age-related disease caused by transthyretin (TTR) proteins that become unstable, misfold, and build up in organs, impairing their function. It is a slowly progressive condition that affects older people, most often Caucasian men over 65 years of age. Heart disease is the hallmark of ATTRwt, but it is commonly preceded by other conditions, such as carpal tunnel syndrome or spinal stenosis.