Late-onset hereditary ATTR V30M amyloidosis with polyneuropathy: Characterization of Brazilian subjects from the THAOS registry.


National Amyloidosis Referral Center, CEPARM, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Neurology, Mayo Clinic, Rochester, MN, USA. Electronic address: [Email]


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.
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 <50 years (EO-V30M), and at age ≥50 years (LO-V30M).
RESULTS : A total of 96 Val30Met patients were symptomatic. LO-V30M (n = 25, 26.0%) had a longer time to diagnosis (mean 5.1 vs. 2.8 yrs.; p = 0.006) and less frequently positive family history (40% vs. 95.8%; p < 0.0001) than EO-V30M. Clinically, subjects with LO-V30M had more imbalance (92% vs. 54.9%; p = 0.006), deep sensory loss (100% vs. 80%; p = 0.0178), electrocardiogram abnormalities (88.9% vs. 59.4; p = 0.0241), and interventricular septum hypertrophy (69.2% vs. 0%; p < 0001) and less frequently sensory dissociation (12% vs. 74%; p < 0.0001). Also, LO-V30M tended to have more severe mean Neurologic Composite Score (101 vs. 70 pts.; p = 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.


Early-onset ATTRv-PN,Familial amyloid polyneuropathy,Hereditary transthyretin amyloidosis,Late-onset ATTRv-PN,Polyneuropathy,

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