OBJECTIVES:  Transthyretin familial amyloid polyneuropathy (TTR-FAP) is a rare, highly disabling, life-threatening disease characterized by progressive sensorimotor and autonomic neuropathy that presents either as sporadic cases or as familial cases, then often in geographical clusters such as Northern Portugal, Sweden, or Japan. It is irreversible and fatal within 7 to 12 years of symptom onset in the absence of therapy. Acknowledging that the epidemiological data of TTR-FAP across Brazil is inadequately understood at present, the aim of our study was to estimate the number of disease symptomatic cases in this country. METHODS:  Analysis of the number of TTR-FAP symptomatic cases in Brazil was performed based on a published epidemiological data of TTR-FAP in Portugal, according to Parman et al., 2016, considering that the Brazil has an important Portuguese influence due to colonization. Using the Portugal epidemiological data, the TTR-FAP prevalence in Brazil was calculated considering the number of resident population in Portugal in 2016 (TTR-FAP prevalence in Portugal = [N TTR-FAP diagnosed patients] / [N resident population]). To estimate the number of Portuguese immigrants in Brazil (luso-Brazilian population), a search of gray literature sources (secondary data) was made. The number of TTR-FAP symptomatic cases in the country was estimated by applying the TTR-FAP prevalence in Portugal to the number of luso-Brazilian population. RESULTS:  TTR-FAP prevalence estimate in Portugal was 1.92 (2000 symptomatic cases diagnosed / 10,4 million resident population). According to found secondary data on gray literature sources, currently 25 million luso-Brazilians live in the country, resulting in approximately 4,800 symptomatic cases of TTR-FAP in Brazil. CONCLUSIONS:  TTR-FAP is a rare disease and devastating. In Brazil, the number of TTR-FAP symptomatic cases was close to the number of the disease symptomatic cases observed in endemic regions, which could be associated with a burden impact to the Brazilian Public Health.