Abstract
The chapter is target to basic definition, epidemiology and diagnostic survey of included diseases. The attention is focused on diffuse metabolic encephalopathies including inborn errors, peroxisomal disorders and mitochondrial encephalopathies.
Inborn errors of metabolism and neurodegenerative diseases are classified according to structural laesions (poliodystrophy, leukodystrophy, subcortical involvement including basal ganglia and spinocerebellar degeneration).