Inborn Errors of Metabolism are a group of diseases which is inherited. The affected baby's body system cannot process normal substances present in milk and food due to lack of certain enzymes. Symptoms are caused by excessive amount of toxic chemicals in the baby's body.
Individually, an Inborn Error of Metabolism is rare. However, technology used for the screening test, called Tandem Mass Spectrometry, allows detection of more than 25 Inborn Errors of Metabolism. The chance of a baby having an Inborn Error of Metabolism is 1 in every 4,000 to 5,000 babies.