Electromyographic findings in cransthyretin (TTR)-related familial amyloid polyneuropathy (FAP)

P. Montagna, L. Marchello, R. Plasmati, A. Ferlini, M. C. Patrosso, F. Salvi

Research output: Contribution to journalArticlepeer-review


Affected members and asymptomatic relatives of 9 Italian families with transthyretin (TTR)-related hereditary amyloidosis carrying different TTR mutations (Met30, Pro36, Ala47, Ala49, Glns89) were followed up with repeated EMG investigations. In 3 patients, spontaneous myoclonic discharges with synkinesia were found in the facial muscles. EMG signs of chronic denervation with features of proximal neural involvement were also found in proximal limb muscles. Neuropathy worsened step-wise with processing clinical stage. Sympathetic skin responses progressively decreased, disappearing in the late stages of the disease. Asymptomatic relatives carrying the TTR mutations had significantly reduced sensory conduction velocities and amplitudes of compound motor action potentials. Follow-up studies in 3 patients after liver transplant showed progression of sensory-motor neuropathy 1 year after the transplant, and a slight improvement 18 months later. Based on our electrophysiological findings and a review of the literature, we propose that TTR-reIated FAP type I be considered not only a peripheral neuropathy, but also a meningoradiculopathy due to deposition of amyloidogenic TTR in the leptomeninges.

Original languageEnglish
Pages (from-to)423-430
Number of pages8
JournalElectroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
Issue number5
Publication statusPublished - Oct 1996


  • Conduction velocity
  • Electromyography
  • Familial amyloid polyneuropathy
  • Liver transplantation
  • Sympathetic skin response
  • Transthyretin-related hereditary amyloidosis

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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