Diagnosis and pathogenesis of late-onset genetic metabolic encephaloneuromyopathies.

The strategy of clinical investigations for the diagnosis of the late-onset neurometabolic diseases is reported. The criteria for the diagnostic suspicion are inheritance and multisystem involvement. The different clinical signs that are the basis for further biological investigations are reviewed. The diagnostic confirmation will be obtained by laboratory analyses, some of which can be easily performed in all hospitals. The pathogenesis of late-onset neurometabolic encephaloneuromyopathies and the clinical consequences of heterozygosity are reported. Finally these disorders are discussed as a useful model for understanding the pathogenesis of some of the most common neurological diseases and of the normal functions of many molecules in the nervous system.