Peripheral nerve abnormalities in adrenomyeloneuropathy

Abstract

Article abstract-Adrenomyeloneuropathy (AMN) is one of the two most frequent phenotypes of X-linked adrenoleukodystrophy. Whether the polyneuropathy in AMN results from primary demyelination or axonal degeneration is uncertain. We examined 23 patients (18 men with AMN and five female carriers with AMN symptomatology), performed electroneurography and EMG, and compared our results with standardized electrodiagnostic criteria for primary demyelination. Both clinically and electrodiagnostically, the lower extremities were most frequently and most severely affected. A longer duration of symptoms was related to more severe pyramidal dysfunction (p < 0.004) and spasticity (p < 0.04), and to a more severe impairment of vibration sense (p < 0.05). There were no correlations between the different electrophysiologic studies and the duration of neurologic symptoms. Only two AMN patients (9%) fulfilled the electrodiagnostic criteria for primary demyelination. However, both had abnormally low compound muscle action potentials, which may have been a reflection of primary axonal degeneration. Six other patients (26%) partially fulfilled the criteria for primary demyelination, of whom five also manifested low compound muscle action potentials. In 15 patients (65%), we found polyneuropathy with predominantly axonal, sensorimotor features. We conclude that the neuropathy in AMN patients is due to primary axonal degeneration.NEUROLOGY 1996;46: 112-118