RESUMEN
BACKGROUND: Despite growing numbers of patients diagnosed with late-onset hereditary ATTR V30M amyloidosis with polyneuropathy (ATTRv-PN), this condition remains poorly characterized in Brazil. OBJECTIVE: Characterize late-onset V30M ATTRv-PN in Brazil. MATERIAL AND METHODS: Demographic and clinical data at the time of enrolment for Brazilian subjects with symptomatic V30M ATTRv-PN were extracted from the ongoing, multinational, longitudinal, observational Transthyretin Amyloidosis Outcomes Survey (THAOS; cut-off date: January 30, 2017). Subjects were divided into those with symptom onset at age <50â¯years (EO-V30M), and at age ≥50â¯years (LO-V30M). RESULTS: A total of 96 Val30Met patients were symptomatic. LO-V30M (nâ¯=â¯25, 26.0%) had a longer time to diagnosis (mean 5.1 vs. 2.8â¯yrs.; pâ¯=â¯0.006) and less frequently positive family history (40% vs. 95.8%; pâ¯<â¯0.0001) than EO-V30M. Clinically, subjects with LO-V30M had more imbalance (92% vs. 54.9%; pâ¯=â¯0.006), deep sensory loss (100% vs. 80%; pâ¯=â¯0.0178), electrocardiogram abnormalities (88.9% vs. 59.4; pâ¯=â¯0.0241), and interventricular septum hypertrophy (69.2% vs. 0%; pâ¯<â¯0001) and less frequently sensory dissociation (12% vs. 74%; pâ¯<â¯0.0001). Also, LO-V30M tended to have more severe mean Neurologic Composite Score (101 vs. 70 pts.; pâ¯=â¯0.1136). CONCLUSIONS: LO-V30M ATTRv-PN is not unusual in Brazil, tending to be more difficult to diagnose and present with a more severe phenotype, with more large nerve fibers and cardiac involvement than EO-V30M. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00628745.