Hereditary transthyretin-related amyloidosis is frequent in polyneuropathy and cardiomyopathy of no obvious aetiology

Ann Med. 2021 Dec;53(1):1787-1796. doi: 10.1080/07853890.2021.1988696.


Background: Hereditary Transthyretin-Related Amyloidosis, a clinically heterogeneous autosomal dominant disease caused by pathogenic variants in the TTR gene, is characterized by the deposition of insoluble misfolded protein fibrils. The diagnosis, especially in non-endemic areas, is typically delayed by 4-5 years; a misdiagnosis due to clinical heterogeneity is common. The study objective was to define the prevalence of Hereditary Transthyretin-Related Amyloidosis in patients with polyneuropathy and/or cardiomyopathy of no obvious aetiology.

Method: A multicenter observational "Epidemiological analysis for the hereditary Transthyretin-Related AMyloidosis"-TRAM study was performed in Germany, Austria, and Switzerland.

Results: A total of 5141 participants were recruited by 50 neurologic and 27 cardiologic specialized centres. Genetic analysis demonstrated a 1.1% Hereditary Transthyretin-Related Amyloidosis positivity rate among patients with polyneuropathy and/or cardiomyopathy of not obvious aetiology. Twenty-one various TTR variants (TTR-positive) were identified. Body Mass Index was lower in the TTR-positive patients as an indicator for the involvement of the autonomic nervous system; the age of onset of clinical manifestations was higher in TTR-positive patients. There were no other genotype-phenotype correlations or the prevalence of specific clinical manifestations in TTR-positive patients.

Conclusions: Our data support the fact that Hereditary Transthyretin-Related Amyloidosis is underdiagnosed in polyneuropathy and cardiomyopathy patients. Routine implementation of genetic testing is recommended in patients with unexplained polyneuropathy and/or cardiomyopathy to accelerate the earlier diagnosis and the time-sensitive treatment initiation.KEY MESSAGESMore than 5.000 participants with CM and/or PNP of no obvious aetiology were recruited in the observational "Epidemiological analysis for the hereditary Transthyretin-Related AMyloidosis" TRAM study and screened for pathogenic TTR variants.The study demonstrated >1% of patients with CM and/or PNP of unclear aetiology are positive for a pathogenic TTR variant.Routine genetic testing is recommended in patients with unexplained CM and/or PNP to accelerate the initial diagnosis and timely treatment initiation.

Keywords: Hereditary transthyretin-related amyloidosis; cardiomyopathy; genetic testing; polyneuropathy.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid Neuropathies, Familial / complications
  • Amyloid Neuropathies, Familial / diagnosis
  • Amyloid Neuropathies, Familial / epidemiology
  • Amyloid Neuropathies, Familial / genetics*
  • Cardiomyopathies / diagnosis
  • Cardiomyopathies / epidemiology*
  • Cardiomyopathies / genetics
  • Genetic Testing
  • Humans
  • Polyneuropathies / diagnosis
  • Polyneuropathies / epidemiology*
  • Polyneuropathies / etiology
  • Prealbumin / genetics*


  • Prealbumin

Supplementary concepts

  • Amyloidosis, Hereditary, Transthyretin-Related

Grants and funding

The study was funded by Alnylam Pharmaceuticals Inc., Cambridge, MA, USA. The funders of this study had no role in the study design, data analysis, data interpretation, or writing of the manuscript.