Disorders of Amino Acid Metabolism

Abstract

The inherited disorders of amino acid metabolism usually result from a missing enzyme or coenzyme which is essential for the breakdown or transport of an amino acid or a group of related amino acids. Some of the disorders have quite specific cutaneous changes, as a variety of amino acids are essential for various skin functions, such as the manufacture of melanin (Chap. 26). In other amino acid disorders, the cutaneous signs are less specific, so that the patient may present with dermatitis and failure to thrive. It is often hard to decide to what extent the skin changes are related to a specific amino acid defect and to what extent they are secondary to malnutrition. Most often the precursor compound that is not adequately converted spills over into the urine, rather than being stored in tissues. Thus, some designate these disorders aminoacidurias.