Electroneurophysiological studies in familial amyloid polyneuropathy--Portuguese type.

Electroneurophysiological studies were performed in 15 patients with familial amyloid neuropathy (ages 29 to 67 years) and in 16 symptom-free members of affected families (ages 9 to 64 years). These studies included needle EMG, motor conduction velocities of deep peroneal and median nerves, sensory conduction velocities, sensory potentials, and nerve potentials of the sural and medium nerves. Results support the view that familial amyloid neuropathy is a peripheral neuropathy with predominantly axonal damage, which affects first the distal segments of the sensory fibres and then the motor fibres. It is suggested that, in some respects, this condition is akin to the dying-back neuropathies. Results also show that it is possible to detect the disease before it becomes obvious clinically, and this has important implications for genetic counseling.