[Motor neuron diseases : Clinical and genetic differential diagnostics].

The causes of degenerative disease of the upper and lower motor neurons are incompletely understood. In this review the current concepts in the clinical and genetic differential diagnostics of motor neuron diseases are presented. Hereditary spastic paraplegia, primary lateral sclerosis, spinal muscular atrophy and amyotrophic lateral sclerosis are explained, structured according to the affection of the upper and/or lower motor neuron. The substantial variability in the presentation and course of motor neuron diseases as well as the lack of specific laboratory tests hinder an early diagnosis. The precise description of the clinical picture, thorough testing of possible differential diagnoses as well as monitoring of the clinical course are essential. Genetic analyses should be offered to patients with a positive family history. Early identification of clinical and genetic subentities of the individual motor neuron diseases is a prerequisite for future neuroprotective interventions.