Hereditary Transthyretin Amyloidosis Cardiomyopathy: The South Florida Experience

Numerous studies have examined distinct populations with hereditary transthyretin amyloidosis (hATTR); however, to the best of our knowledge, no studies have focused on the hATTR population of South Florida, a region characterized by its diverse population, with a prominent Black, Afro-Caribbean, and Hispanic presence. We performed a retrospective observational study of patients diagnosed with hATTR cardiomyopathy from 2010 to 2020 at the University of Miami Hospital located in Miami, Florida. Patients with either a positive endomyocardial biopsy or Technetium-99m Pyrophosphate scan were selected and classified into hATTR or wild-type ATTR (ATTRwt), based on genetic testing results. A subsequent electronic medical record review was performed, and baseline characteristics were obtained for both groups. A total of 144 patients were identified to have ATTR and were included in this study. Of these patients, 36% had hATTR (n = 52), and 64% had ATTRwt (n = 92). Baseline age, gender, and race characteristics in the hATTR and ATTRwt groups were consistent with previous observational studies. When comparing our findings with preliminary data from the Transthyretin Amyloidosis Outcome Survey reported in 2016, we observed a higher proportion of Val122Ile (75% vs 44% of all hATTR cases), a lower proportion of hATTR cases (36% vs 52%), and a higher proportion of ATTRwt (64% vs 48%). Preliminary data from the Transthyretin Amyloidosis Outcome Survey did not report specific data about Hispanic patients with hATTR, with only 7% of all cases reported being from non-Caucasian and non-Black patients. Hispanic patients represented 25% of all hATTR cases within our population, with 69% of them being positive for the Val122Ile allele. In conclusion, the large presence of Black and Afro-Caribbean subjects within the South Florida region, in combination with its prominent Hispanic population and the high proportion of adults aged more than 65 years, results in a unique population composition that could help explain the higher-than-expected frequency of Val122Ile and ATTRwt cases observed within our study.