Metabolics: PKU, MSUD, etc

Metabolism is a term used to describe the chemical reactions that occur within the body. Chemical reactions need enzymes to help to make them happen. An enzyme is made from protein and is important in helping to break down substances in the body. Our genetic make-up and the ability to produce the right enzymes are closely linked.

An Inborn Error of Metabolism is an inherited condition (via genes) that results from not having enough of an enzyme that is needed to break down amino acids (the building blocks of protein), fats or carbohydrates. Symptoms occur from not having enough of the substance that would have been broken down by the enzyme or from having too much of the substance that the body was unable to breakdown. These conditions are normally diagnosed shortly after birth or in childhood.

There are many different types of inborn errors of metabolism, although they are actually quite rare. PKU (phenylketonuria) is an example of one of these conditions. The body cannot breakdown, a substance called phenylalanine, an amino acid, one of the building blocks of protein. The condition is managed by a strict diet that reduces the amount of protein, and therefore phenylalanine, that is eaten from food. A special protein substitute is taken to help normal growth and development. All babies are checked for PKU at birth as using the heel-prick test.