Isovaleric acidemia is an inherited condition in which abnormal metabolism of the amino acid leucine causes the fatty acid isovaleric acid to build up in the blood and urine.
Amino acids are the building blocks of proteins. After eating proteins, the body ‘metabolizes’ or breaks them down into amino acids. Animal proteins include dairy products, meat, eggs and fish. Proteins are also found in plants including soy, legumes, grains and nuts. The body uses the amino acids to make its own proteins essential for life – for example enzymes; structural proteins in muscles, hair, skin, cells and cartilage; proteins that generate movement in muscles; or those involved in cell functioning or immune responses. In periods of fasting or illness, proteins in the body can be broken down to generate energy. Leucine is an essential amino acid meaning that it is not made by the body. Therefore, this amino acid comes from ingested protein or from the breakdown of previously ingested and stored proteins. Foods with a high-leucine content include beef, fish, chicken, soy beans, lentils and nuts.
Similarly, fatty acids are the building blocks of fats used by our bodies for energy.
Isovaleric acidemia (-aemia meaning ‘in the blood’) is also known as isovaleric aciduria (-uria meaning ‘in the urine’) or isovaleric acid CoA dehydrogenase (IVD) deficiency, which describes the enzyme deficiency at its root.
Accumulation of isovaleric acid damages the brain and nervous system, leading to learning problems, seizures and loss of movement or ‘motor’ ability.