Electrophysiological demyelinating features in hereditary ATTR amyloidosis

AbstractObjective: To elucidate the electrophysiological demyelinating features in patients with hereditary ATTR amyloidosis that may lead to a misdiagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP).Methods: In 102 patients with hereditary ATTR amyloidosis (85 Val30Met and 17 non-Val30Met; 37 and 65 from endemic and non-endemic areas, respectively), results of motor nerve conduction studies (MNCSs) with a 2-Hz low-cut filter in the unilateral ulnar and tibial nerves were retrospectively investigated to assess whether each MNCS parameter demonstrated demyelinating features that fulfil the European Federation of Neurological Societies/Peripheral Nerve Society electrodiagnostic (EFNS/PNS EDX) criteria for CIDP.Results: Thirteen patients with low compound muscle action potential (CMAP) amplitude in the tibial nerve (0.7 ± 0.7 mV) and prolonged distal CMAP duration in the ulnar nerve satisfied the definite EFNS/PNS EDX criteria for CIDP. Abnormal temporal dispersion and prolongation of distal...