Familial transthyretin amyloidosis
Other Names for this Disease
- Amyloidosis Transthyretin related
- Amyloidosis, hereditary, transthyretin-related
- Familial amyloid polyneuropathy
- Transthyretin amyloid neuropathy
- Transthyretin amyloid polyneuropathy
How might familial transthyretin amyloidosis be treated?
Familial transthyretin amyloidosis is a slowly progressive condition characterized by the buildup of abnormal deposits of a protein called amyloid (amyloidosis) in the body's organs and tissues. Amyloid deposits in the nerves of the peripheral nervous system result in a loss of sensation in the extremities (peripheral neuropathy). The autonomic nervous system (which controls involuntary body functions such as blood pressure, heart rate, and digestion) as well as the central nervous system (brain and spinal cord) may also be affected. Other areas of the body affected include the heart, kidneys, eyes, and gastrointestinal tract. The age at which symptoms develop varies widely among affected individuals, and may be between ages 20 and 70 years. Mutations in the TTR gene cause the condition. Although it is inherited in an autosomal dominant pattern, not all people who have a TTR gene mutation will develop familial transthyretin amyloidosis.
There are three major forms of familial transthyretin amyloidosis, which are distinguished by their symptoms and the body systems they affect. The neuropathic form of transthyretin amyloidosis primarily affects the peripheral and autonomic nervous systems, resulting in peripheral neuropathy and difficulty controlling bodily functions. The leptomeningeal form of transthyretin amyloidosis primarily affects the central nervous system. The cardiac form of transthyretin amyloidosis affects the heart. To read more about the different forms of familial transthyretin amyloidosis, click here.
- Complete neurologic assessment including baseline nerve conduction studies (which measure the speed at which nerves conduct impulses)
- Evaluation of the heart for cardiomyopathy and to evaluate amyloid deposition in the heart
- Gadolinium-enhanced MRI of the brain and spinal cord to evaluate central nervous system (CNS) amyloidosis
- Ophthalmologic (eye) evaluation
- Evaluation of renal function
Treatment for familial amyloid polyneuropathy may include:
In terms of preventing some signs and symptoms associated with the condition, orthotopic liver transplantation (OLTX) is reportedly the only effective therapy for the neuropathy associated with familial transthyretin (TTR) amyloidosis. This type of liver transplantation involves replacing the recipient liver with a donor liver. This procedure removes the main production site of the abnormal protein. Successful OLTX results in rapid disappearance of the harmful protein and thus stops the progression of neuropathy. It has been recommended that individuals with the condition considering OLTX be at an age younger than 60 years; have a disease duration less than five years; have either polyneuropathy that is restricted to the lower extremities (legs) or autonomic neuropathy alone; and have no significant cardiac (heart) or renal (kidney) dysfunction. OLTX is reportedly not effective in the non-neuropathic forms of familial transthyretin amyloidosis (i.e., cardiac amyloidosis, leptomeningeal amyloidosis, and familial oculoleptomeningeal amyloidosis). Individuals with leptomeningeal involvement may not be candidates for liver transplantation.
- Transthyretin amyloidosis. Genetics Home Reference (GHR). 2009; http://ghr.nlm.nih.gov/condition/transthyretin-amyloidosis. Accessed 7/15/2010.
- Yoshiki Sekijima, Kunihiro Yoshida, Takahiko Tokuda, Shu-ichi Ikeda. Familial transthyretin amyloidosis. GeneReviews. September 15, 2009; http://www.ncbi.nlm.nih.gov/books/NBK1194/. Accessed 6/29/2011.