The objective of this prospective observational study is to periodically monitor pre-symptomatic subjects carrying a mutation of Transthyretin (TTR), identified in the context of a family screening of affected proband, through instrumental methods and clinical scales in order to identify the first signs of clinically significant organ involvement by the disease. Healthy asymptomatic carriers will be subjected to regular monitoring through clinical evaluations and instrumental investigations defined by the consensus group (Conceicao et al.) in order to validate the criteria defined by this group to define the onset of the disease. A subgroup of carriers with scales and instrumental tests negative for damage to the peripheral nervous system or cardiac, but with subjective symptoms compatible with the disease, will be subjected to further instrumental tests not indicated by consent.

Inclusion criteria

1. Pre-symptomatic carriers of TTR mutation in regular follow-up at the Centres.
2. Signature of the written informed consent.
3. Age not less than 10 years compared to the age of onset of the relative with the youngest age of onset and/or a history of bilateral carpal tunnel syndrome undergoing surgery.

Exclusion criteria

• Other causes of neuropathies (diabetes; MGUS; alcoholism; vitamin deficiency).
• Other causes of hypertrophic heart disease.

Data from pre-symptomatic carriers who have signed the written informed consent, in regular follow-up at the Centres, will be included in the study. Carriers recruited should be no less than 10 years of age compared to the age of onset of the affected relative with the youngest age of onset or should have a history of bilateral carpal tunnel syndrome undergoing surgery.