ABSTRACT
The most practical form of treatment of inborn errors of metabolism is the removal of the component or substrate that is not metabolized. As the understanding of the inborn errors of metabolism has expanded, dietary management has become the hallmark for treatment in an effort to ameliorate the severe consequences of many of these genetic defects. Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism that occurs in approximately one in 10,000 to 15,000 births in the United States. The successful treatment led to mandatory newborn screening for this disease in the United States. The biochemical findings on patients with untreated PKU include elevated levels of phenylalanine in blood, urine, and spinal fluid. The dietary treatment of phenylketonuria involves the restriction of phenylalanine; however, since phenylalanine is an essential amino acid, adequate amounts should be provided. It is also important to be sure that products beyond the metabolic block are provided in adequate amounts.
