Poor Yield of Routine Transthyretin Genetic Screening in Patients with Idiopathic Neuropathy

Objective: The aim of our study was to determine the prevalence of transthyretin familial amyloid polyneuropathy (TTR-FAP) within patients with idiopathic neuropathy in a North American population. Background: Transthyretin familial amyloid polyneuropathy (TTR-FAP) is caused by a mutation in the transthyretin (TTR) gene. Although classically described as rapidly progressive and life-threatening, recent studies on TTR-FAP show significant genetic and phenotypic heterogeneity depending on geographic localization. In addition, two gene silencing therapies have recently been proven efficacious in phase III trials. Given the severity of the natural course of the disease and the new possibilities for therapeutics, there is increasing emphasis on the importance of adequately recognizing and testing for TTR-FAP. Design/Methods: We sequenced the TTR gene in a cohort of patients with idiopathic neuropathy. Genetic screening was performed in 110 patients from two neuromuscular clinics in Montreal, Canada. Results: No variants of unknown significance or pathogenic mutations were detected in the TTR gene. Conclusions: In conclusion, our study confirms that TTR-FAP is a rare entity in our patient population, and that diagnostic yield of screening all patients with idiopathic neuropathy is very low. This study’s results are in accordance with two recently published European studies using similar methodology. Disclosure: Dr. Namiranian has nothing to disclose. Dr. Massie has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Sanofi, CSL Behring. Dr. Massie has received research support from Octapharma.. Dr. Chalk has nothing to disclose.