Monitoring of asymptomatic family members at risk of hereditary transthyretin amyloidosis for early intervention with disease-modifying therapies

Background: Hereditary transthyretin (ATTRv) amyloidosis is an adult-onset, systemic disorder caused by mutations in the transthyretin (TTR) gene. As ATTRv amyloidosis is inherited in an autosomal dominant manner, family members of the patients are at risk of developing the disease. Methods: With an objective of discussing recommendations on monitoring of family members for early diagnosis of ATTRv amyloidosis, we held a medical advisory board meeting in Tokyo, Japan, in October 2017. Results: Our recommendations are summarized as follows: periodic follow-up genetic counseling should be offered to asymptomatic gene mutation carriers; follow-up assessments should be started when the carriers are still asymptomatic to test for amyloidosis onset, irrespective of TTR genotype and age at onset in the particular family. We suggest annual routine assessments and in-depth assessments every 3-5 years, with the frequency of these increased as required. Periodical monitoring of asymptomatic gene mutation carriers is crucial for attending physicians to detect early signs or symptoms of the disease and start disease-modifying therapy (DMT). Conclusions: The monitoring strategy for asymptomatic TTR gene mutation carriers should progress toward rapid diagnosis and early intervention with DMT. This approach may be more appropriate for countries with more resources.