This volume is 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. Moreover, due to the spectacular development of molecular biology, several new genetic mutations have been recognized as disease agents, including: the alteration of recently discovered mitochondrial DNA; reasons for phenotype variability have been better understood; and methods for prenatal diagnosis have been improved in regard to precociousness and safety. The book provides an introduction on basic sciences specifically relevant to this disease group, then focuses on each subgroup in turn: hyperphenylaninaemias; mitochondrial encephalomyopathies, organic acidoses, urea cycle defects, lysosomal storage and peroxysomal disorders. Finally, a discussion of long-term follow-up and family-related issues also reporting the results of a four-year research project by the Mariani Foundation on the neuro-psychiatric development of the patients. The Mariani Foundation was established in 1984 with the purpose of assisting children with afflictions of the nervous system. The goal is to not only provide material assistance, but also to be instrumental in complementing the overall educational and research programmes in paediatric neurology.