[Hereditary motor sensory neuropathies]

The descriptive term "hereditary motor sensory neuropathy (HMSN)" includes a group of disorders of different nosology which besides heredity show a progressive distal symmetrical motor sensory neuropathy as a common clinical feature. The etiology of these disorders is probably different. According to electrophysiological and morphological findings two major types of HMSN can be distinguished from each other: 1. The neural type (HMSN, type I) is characterized by axonal degeneration, segmental demyelination and hypertrophic changes. The nerve conduction velocity in this type is significantly slowed. 2. The neuronal type (HMSN, type II) shows axonal degeneration with secondary segmental demyelination and no hypertrophic nerve changes. The nerve conduction velocity in these cases is normal or insignificantly decreased. This paper includes a historical review and a detailed description of the clinical, electrophysiological and morphological findings of the two major types of HMSN. The current classifications of HMSN are cited and critically discussed.