Mutation as the cause of ATTR cardiomyopathy is more common than believed

Background Interest in transthyretin amyloid cardiomyopathy (ATTR-CM) is growing due to improved diagnostics and disease modifying therapy.

Methods We investigated the symptoms and disease characteristics in a Finnish ATTR-CM patient cohort participating in a Nordic study (n=19). We also evaluated the development of ATTR-CM diagnosis numbers in national care registries in 2017–2021 and the prevalence of two known TTR gene mutations using the FinnGen register.

Results The mean age of patients was 74.2 years. The most common disease manifestations were atrial fibrillation (n=13), heart failure (n=10), and carpal tunnel syndrome (n=7), and the most common comorbidity was hypertension (n=7). The number of ATTR-CM diagnoses increased by 1.7-fold during the years 2017–2021, exceeding 120 annual diagnoses in 2021. In the population data, the prevalence of TTR mutations Val122Ile and Val30Met corresponded to the prevalence of hereditary ATTR-CM in European population.

Conclusions The symptoms of Finnish ATTR-CM patients corresponded to the observations in other populations. The rapid increase in diagnoses is indicative of underdiagnostics. The numbers of carriers of the two examined TTR mutations in Finland were higher than expected, highlighting the importance of genetic testing in diagnostics.