Transthyretin amyloidosis (ATTR) involves progressive deposition of fibrillar transthyretin (TTR) protein, whose physiological function includes carrying thyroid hormones and vitamin A. Transthyretin amyloidosis often affects elderly individuals [wild-type ATTR (ATTRwt)], likely because of an age-related decline in the homeostatic mechanisms that regulate protein metabolism. The gene discussed is TTR; the disease is Familial transthyretin-related amyloidosis.