Clinical features of familial amyloid polyneuropathy carrying transthyretin mutations in four Chinese kindreds

Transthyretin-related familial amyloid polyneuropathy (TTR-FAP) is a rare hereditary disorder, characterized by a length-dependent polyneuropathy and dysfunction of various organs. Wide phenotypic heterogeneity makes early diagnosis difficult. In this study, we reviewed the clinical and electrophysiological features of four unrelated Chinese families with genetically confirmed TTR-FAP. Sequence analysis of TTR gene revealed the presence of four different mutations: Thr49Ala(p.Thr69Ala), Leu55Arg(p.Leu75Arg), Tyr116Ser(p.Tyr136Ser), and Ala36Pro(p.Ala56Pro) from six affected patients and two asymptomatic individuals. Two mutations, Thr49Ala(p.Thr69Ala) and Tyr116Ser(p.Tyr136 Ser), were detected in Chinese FAP patients for the first time. All affected patients manifested a progressive sensorimotor polyneuropathy starting in the lower limbs. The majority of the examined patients displayed cardiomyopathy and vitreous opacities. To avoid misdiagnosis, clinicians should consider screening for TTR variants in patients presenting with progressive polyneuropathy of undetermined origins.