ABSTRACT
Of the over 3000 inherited metabolic disorders described in the literature (1,2), many are very rare, but because these disorders are numerous, they contribute significantly to morbidity and mortality, especially during childhood. Dietetic treatment plays an important role in the manage ment of at least a few of these diseases. Therapeutic diets used with varying degree of success act by (3):
1. preventing the accumulation of a substrate and its derivative, as in a low-phenylalanine controlled diet for phenylketonuria
2. providing a metabolite that becomes rate-limiting as a result of a metabolic block, e.g., the administration of arginine in children with argininosuccinase deficiency
3. providing a metabolite whose deficiency can be dangerous, as in a diet to prevent hypo glycemia in glucose-storage disease
4. providing a cofactor or precursor, e.g., large doses of pyridoxine for a variant of homocystinuria.
