Clinical measures in transthyretin familial amyloid polyneuropathy

IntroductionThis observational, cross-sectional, single-center study aimed to identify instruments capable of measuring disease progression in transthyretin familial amyloid polyneuropathy (TTR-FAP). MethodsThe relationship between disease stage and Neuropathy Impairment Score-Lower Limbs (NIS-LL) and Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) total score was assessed in 61 (stages 1-3) patients with TTR-FAP (V30M variant) and 16 healthy controls. Composite measures of large- and small-nerve fiber function, and modified body mass index (mBMI) were also assessed. ResultsOrdinal-based NIS-LL and Norfolk QOL-DN scores discriminated between disease stages (P<0.0001 for NIS-LL and Norfolk QOL-DN). Longer disease duration correlated with worse NIS-LL and Norfolk QOL-DN. Karnofsky performance score declined progressively by disease stage. Composite measures of nerve fiber function differentiated stage 1 from stage 2 disease. The mBMI declined with advancing disease. ConclusionsNIS-LL, Norfolk QOL-DN score, composite endpoints of nerve fiber function, and mBMI are valid, reliable measures of TTR-FAP severity. Muscle Nerve55: 323-332, 2017