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ATTR-CMATTR-CMATTR-CM HomeAbout ATTR-CMMechanism of DiseaseWild-Type ATTR-CMHereditary ATTR-CMSuspect ATTR-CMDetect ATTR-CMResourcesMaterialsVideosTreatment Option
ATTR amyloidosis is due to the misfolding of TTR protein1 TTR is a transport protein for a thyroid hormone (thyroxine [T4]) and is a retinol-binding protein2
  • Produced mainly in the liver, but there is also some production in the choroid plexus (brain) and retinal epithelium (eye)2
  • TTR protein plays an important role in the body. The long-term impact of TTR reduction in humans is unknown2,3
  • The complete absence of TTR in humans has not been reported2
The physiologic role of TTR is not fully defined, but the growing body of evidence suggests TTR has additional important functions.2Biological functions of TTR from mouse and human studies2* Human and mouse TTR share 80% similarity at the amino acid level, so it may be expected that insights into the physiologic function of human TTR could be gained through the generation of TTR knockout mice.2Other important functions of TTR that are independent of protein transport:

Neuroprotective effects have been shown in both the peripheral nervous system (PNS) and the central nervous system (CNS) in animal and clinical studies2

Protection against neurodegeneration and Alzheimer disease in a mouse model2

The pathogenesis of ATTR amyloidosis is caused by the destabilisation, not production, of TTR protein tetramers2

In ATTR-CM, a TTR gene mutation or age-related changes destabilise the protein tetramers, which separate into monomers and then misfold and aggregate into amyloid fibrils that deposit in the heart and other organs over time.2,4

Fibrils can deposit is multiple areas5

Because amyloid fibrils can deposit in different parts of the body, including the heart and nerves, some patients may present with a mixed phenotype, namely, symptoms of both cardiomyopathy and polyneuropathy.2,5

Suspicion of cardiac involvement should prompt immediate cardiac evaluation to assess for ATTR-CM.6 ​​​​​​​

Wild-Type ATTR-CM > LoadingReferences:Coelho T, Ericzon B, Falk R, et al. A Guide to Transthyretin Amyloidosis. Clarkston, MI: Amyloidosis Foundation; 2016. Accessed October 28, 2019.Liz MA, Coelho T, Bellotti V, Fernandez-Arias MI, Mallaina P, Obici L. A narrative review of the role of transthyretin in health and disease. Neurol Ther. 2020;9(2):395-402. doi:10.1007/s40120-020-00217-0Adams D, Ando Y, Beirão JM, et al. Expert consensus recommendations to improve diagnosis of ATTR amyloidosis with polyneuropathy. J Neurol. 2021;268(6):2109-2122. doi:10.1007/s00415-019-09688-0Ruberg FL, Berk JL. Transthyretin (TTR) cardiac amyloidosis. Circulation. 2012;126(10):1286-1300. doi:10.1161/CIRCULATIONAHA.111.078915Maurer MS, Bokhari S, Damy T, et al. Expert consensus recommendations for the suspicion and diagnosis of transthyretin cardiac amyloidosis. Circ Heart Fail. 2019;12(9):e006075. doi:10.1161/CIRCHEARTFAILURE.119.006075Garcia-Pavia P, Rapezzi C, Adler Y, et al. Diagnosis and treatment of cardiac amyloidosis: a position statement of the ESC Working Group on Myocardial and Pericardial Diseases. Eur Heart J. 2021;42(16):1554-1568. doi:10.1093/eurheartj/ehab072Dorbala S, Ando Y, Bokhari S, et al. ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI expert consensus recommendations for multimodality imaging in cardiac amyloidosis: part 1 of 2—evidence base and standardized methods of imaging. J Nucl Cardiol. 2019;26(6):2065-2123. doi:10.1007/s12350-019-01760-6. Addendum: J Nucl Cardiol. Published online July 1, 2021. doi:10.1007/s12350-020-02455-z
ATTR-CM Discover more about ATTR-CM What imaging modalities help raise suspicion of ATTR-CM?

Gain a deeper understanding of echocardiography and cardiac magnetic resonance (CMR).

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Detect ATTR-CM noninvasively with nuclear scintigraphy7

Review the evidence and consensus recommendations for diagnosis.

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