An amyotrophic lateral sclerosis-like syndrome revealing an amyloid polyneuropathy associated with a novel transthyretin mutation

Abstract

Familial amyloid polyneuropathy (FAP) is typically a predominantly sensory and autonomic neuropathy with progressive and late motor involvement leading to death within 10 years. Recently, prognosis was transformed with liver transplantation. We report an atypical sporadic pure motor and bulbar neuropathy initially mistaken for amyotrophic lateral sclerosis (ALS) in a 50-year-old Malian man. The diagnostic procedure of this clinical purely motor and bulbar neuropathy disclosed amyloid deposits on nerve biopsy which led to the identification of a new Val93Met mutation of transthyretin. This case was also remarkable by its slow progression. This report confirms the motor phenotype of TTR-FAP. That should be considered in the differential diagnosis of motor neuron diseases in order to start accurate therapy.