This book is dedicated to an update on metabolic disorders and their consequences on the developing nervous system. In the last ten years, major scientific advances in biochemical diagnosis have enabled the identification of many new disease entities, as well as a better classification of clinical symptoms and their correlation to biochemical defects. This volume provides an introduction to basic sciences specifically relevant to this disease group, then focuses on each subgroup in turn: hyperphenylalaninaemias, mitochondrial encephalomyopathies, organic acidoses, urea cycle defects, lysosomal storage and peroxylsomal disorders. Finally, a discussion of long term follow-up and family related issues also reports the results of a four-year research project led by the Mariani Foundation.