Transthyretin amyloidosis (ATTR) is a disease where the normally occurring transthyretin (TTR) protein falls apart and forms amyloid, a sticky plaque- like substance that accumulates in different organs in the body and can cause damage to the organ. There are two ways that the TTR protein can fall apart. One way occurs as a person ages, where the normal TTR protein can fall apart and form amyloid that may no longer be sufficiently cleared by the body. This type of ATTR is known as wild-type ATTR (ATTRwt). The other way occurs when a person inherits a defective TTR gene that causes the TTR protein to spontaneously fall apart. This form of the disease is known as variant ATTR (ATTRv) and can be detected in adults by a genetic test of their TTR gene before they age.