[Myelin diseases affecting both the central and the peripheral nervous system]

Myelin is synthesized by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system. A combined dysmyelinating/demyelinating process in the central nervous system and in the peripheral nervous system occurs only rarely. A brief review of these conditions is given in this article. Occasionally, coexistence of multiple sclerosis and chronic inflammatory demyelinating polyneuropathy is reported. Cases of multiple sclerosis, hypertrophic polyneuropathy, and central nervous system demyelination in Miller-Fisher syndrome and Guillain-Barré syndrome have also been reported. Concurrent dysmyelination in the central nervous system and peripheral nerve demyelination are common in metachromatic leukodystrophy, Krabbe disease and adrenoleukodystrophy. A Norwegian family with adult-onset demyelinating disease affecting both the peripheral and central nervous system has recently been described. The mode of inheritance is probably autosomal dominant, but its exact nature remains unknown.