What type of study is this?

This is a Cohort Study study (also classified as: Human Clinical Trial).

November 9, 2025Open Access

Clinical study of patients with familial amyloidotic polyneuropathy at Pedro Ernesto University Hospital

MJMárcia Rodrigues JardimUniversidade Federal do Rio de Janeiro LALígia AndradeUniversidade do Estado do Rio de Janeiro LCLarissa Bittencourt de CarvalhoUniversidade do Estado do Rio de Janeiro

Key Points

Symptomatic patients with familial amyloidotic polyneuropathy show variable age and gender distribution, with a mean age of 49 years.
Neurological examination indicates diverse outcomes, with up to 76.9% reporting initial neurological symptoms related to sensory neuropathy.
Retrospective study analyzed data from patients with ATTR gene mutation to identify phenotypic variability and common mutations.
Understanding the nature of familial amyloidotic polyneuropathy is crucial for better diagnostics and treatment planning in Brazil.

Abstract

Background: Hereditary transthyretin amyloidosis (ATTRv) is a rare autosomal dominant disease associated with mutations in the transthyretin gene. Patients present with various symptoms related to sensory, motor and autonomic neuropathy, as well as gastrointestinal, ocular, cardiac, renal and orthopedic symptoms, resulting from the deposition of transthyretin amyloid fibrils in multiple organs. The progressive nature of ATTRv amyloidosis requires pre- and post-onset monitoring of the disease. It is a rare genetic disease considered endemic in some countries. There is phenotypic variability, making it a rare and very heterogeneous disease. Method: This is a retrospective study, through the analysis of the database of the Peripheral Neuropathy outpatient clinic of the Pedro Ernesto University Hospital that has ATTR gene mutation. Data from symptomatic and asymptomatic patients followed at the service who underwent genetic testing for the ATTR gene mutation between June 2012 and June 2024 were included. All patients underwent clinical evaluation, including neurological examination, disability score (Polyneuropathy disability score, PND), clinical cardiological Evolution, and neurophysiological and imaging studies. Results: A total of 60 individuals, over 18 years of age, with the ATTR gene mutation were included. Forty individuals (66.6%) were female, mean age 49 years (18-77 years). Forty-four (73.3%) individuals were symptomatic, of which 4 (6.5%) had already died at the time of analysis. The most frequent mutation was val30met (38.3%) followed by val122ile (26.6%), ile 127val (13.3%), Phe84leu (8.3%). Eight individuals (13.3%) had a history of consanguinity. Patients registered at the outpatient clinic. Twenty-three patients (52.2%) had a mixed phenotype. PND 0 36.9%, PND I 32.6%, PND II 7.4% and PND III 19.5%. The first symptoms were neurological (76.9%), with 20.5% presenting paresthesia in the upper limbs, 55.8% paresthesia in the lower limbs, neuropathic pain in 26.4%, cardiac pain occurred in 13% of cases, dysautonomia in 6.5% and weight loss in 5.8%. ATTRv has a heterogeneous clinical presentation, varying between individuals and geographic locations. Brazil is a country with a large number of ATTRv cases. Still, there are no epidemiological studies that could help in public policies to improve early diagnosis and indicate high-cost treatments. Currently, we can conduct research through genetic studies more easily. We have demonstrated the presence of mutations that seem to be more frequent than previously determined. Conclusion: The description of epidemiological data from centers monitoring patients with ATTRv is extremely important to understand the nature of this rare disease in Brazil.

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