Transthyretin is a protein produced primarily in the liver and the choroid plexus of the brain. It plays a crucial role in transporting vitamin A and thyroxine, a hormone produced by the thyroid gland. Transthyretin is essential for maintaining proper levels of these substances in the bloodstream. In certain conditions, such as transthyretin amyloidosis, transthyretin can misfold and form amyloid fibrils, leading to tissue damage and organ dysfunction. This misfolding can result from genetic mutations or age-related changes, making it important for researchers to study transthyretin for potential treatments and therapies.