Abstract
The phenylalanine hydroxylating system and its related disorders have been intensely investigated during the past decade. This article discusses on some of the newer developments in the study of the physiology and pathophysiology of human phenylalanine metabolism: 1) the phenylalanine hydroxylating system, 2) the early diagnosis of hyperphenylalaninemia syndromes, 3) the molecular basis for phenotypic heterogeneity of phenylketonuria, 4) the prenatal diagnosis of phenylketonuria, and 5) hyperphenylalaninemia caused by defects in tetrahydrobiopterin metabolism.
