Hereditary Transthyretin Amyloidosis in Brazilian Amazon Caused by a Globally Rare Variant Predominant in Asia.

BACKGROUND

Hereditary transthyretin amyloidosis (ATTRv) exhibits marked phenotypic heterogeneity. The p.Asp58Ala variant is globally rare and has not been reported in major Brazilian epidemiologic studies.

CASE SUMMARY: We report 10 patients with ATTRv-p.Asp58Ala, including 6 index cases and 4 identified through family screening. Mean left ventricular ejection fraction was 64.7%, with a mean interventricular wall thickness of 14.1 mm and a mean posterior wall thickness of 12.9 mm. Mixed cardiac and neurologic involvement predominated (60%), followed by asymptomatic (30%) and isolated cardiac (10%) phenotypes. Among 7 patients under follow-up, 2 receive tafamidis and 1 receives inotersen.

DISCUSSION: Similar to Korean and other Asian cohorts, mixed phenotypes predominated, although our series showed substantial cardiac involvement and significant mortality.

TAKE-HOME MESSAGES: p.Asp58Ala is a rare ATTR variant, previously described mainly in Asian populations. Its identification in the Amazon region suggests a possible previously unreported regional clustering in Brazil.