Transthyretin-related familial amyloid polyneuropathy (ATTR-FAP) in Poland — genetic and clinical presentation

Background. Transthyretin-related familial amyloid polyneuropathy (ATTR-FAP) is a rare, progressive, hereditary, highly disabling multisystem disorder. ATTR-FAP phenotypes differ according to the type of TTR mutation, geographic region and other as yet unidentified factors. The aim of this study was to establish the clinical and genetic characteristics of Polish patients. Methods and patients. Clinical data and necessary examinations were collected from patients diagnosed with ATTR-FAP at the Department of Neurology of Medical University of Warsaw between 1970 and 2019. Results. 16 patients from eight unrelated families with five different TTR mutations were identified. The family with Val71Ala TTR mutation presented with early onset severe progressive polyneuropathy, with marked visual symptoms in a few patients. The next family with Ile73Val TTR mutation developed symptoms in middle age, and presented with mixed neuropathic and cardiologic phenotype. Four unrelated families were found to have the Phe33Leu TTR mutation with mixed neuropathic and cardiologic phenotype and late onset of symptoms. Other TTR mutations identified were: Val30Met and Asp38Val, both with late onset sensory, motor and autonomic neuropathy. Conclusion. Polish ATTR-FAP cases presented with heterogeneity typical for non-endemic areas. Phe33Leu TTR mutation was the most common, found in four unrelated families.