Inborn metabolic disorders represent a heterogeneous group of monogenic disorders caused by defects in a biochemical pathway due to the deficiency or abnormality of an enzyme, its cofactor, or a transporter, resulting in the accumulation of a substrate or toxic metabolite, or deficiency of a product. This chapter deals with biochemical changes resulting from inborn metabolic errors. It starts by approaching the historical perspective, worldwide prevalence, mortality, classification, and most frequent disorders, then focusing on advances in terms of diagnosis and treatment.
