Inborn errors of metabolism are rare genetic disorders that affect the body’s metabolism. Metabolism describes the body’s ability to convert food and drink into energy, as well as get rid of certain wastes made during that process. It’s a complex process that uses many different chemicals, enzymes, hormones, cells, and organs to work properly.
Enzymes are special proteins that cause chemical reactions. When we eat, the digestive system uses enzymes to break down the food into sugars, amino acids, fatty acids, and other chemicals that can be used by the body. The body uses these chemicals as fuel or energy, as well as to build or repair tissues. Anything that can’t be used by the body is waste. Enzymes can also help convert or break down wastes so they can be removed from the body.
With inborn errors of metabolism, certain enzymes don’t work properly or the body doesn’t make enough of an enzyme. This disrupts the process of metabolism. The body may be blocked from using substances it needs to function. Or, waste substances can build up in the body and become toxic. These issues can cause health problems, including serious developmental problems in young children.
Diagnosis and Tests
Newborn screening tests are given at birth that can identify some inherited metabolic diseases. Because there are many conditions that can show a variety of symptoms, your doctor may use more than one test. A test that shows abnormal results will be followed with a second test to confirm the diagnosis.
Most tests are done to a urine or blood sample to detect amino acids or other substances that might be present in the body. For a few disorders, your doctor might need to do a test on tissues from the liver, brain, muscles, bone marrow, or skin; or they may request specific DNA testing.
