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

OBJECTIVE: 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. METHODS: We report an atypical sporadic pure motor and bulbar neuropathy initially mistaken for amyotrophic lateral sclerosis (ALS) in a 50-year-old Malian man. RESULTS: 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. CONCLUSIONS: 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.