ABSTRACT

This chapter discusses Basic mechanism underlying metabolic disorders, and its Classification: Group 1; Rapid toxic accumulation of a small molecule, Group 2; Lack of energy, Group 3; Defects in the synthesis of large molecules resulting in a dysmorphic child, Group 4; Defects in the metabolism of large complex molecules, Group 5: Mitochondrial diseases, Hyperlipidaemias, and Porphyrias. It provides clinical manifestations, prognostic features, investigations, and management of the diseases. Inborn errors of metabolism are inherited biochemical disorders and are generally autosomal recessive caused by single gene disorders. They are individually rare yet collectively not uncommon. Metabolic diseases usually affect children although increasingly adult phenotypes are being described. Due to the rarity of the individual conditions, the multitude of possible presentations and the perceived complexity of the investigations required, metabolic diseases are likely to be frequently undiagnosed.