An enzyme deficiency is genetic condition characterized by inability to produce an enzyme or underproduction of that enzyme, leading to health problems caused by problems with the metabolism. Some examples of deficiencies include phenylketonuria, acute intermittent porphyria, alkaptonuria, and Lesch-Nyhan syndrome. These conditions are part of a larger family of diseases classified as inborn errors of metabolism. Such conditions may be inherited from one or both parents, or the result of spontaneous mutations.
Enzymes are specialized proteins built in the body to accomplish a variety of tasks. In the metabolism, enzymes help the body break down, transport, and transform food products people ingest. They are found in the digestive tract, liver, kidneys, and other structures of the body and are involved at every level, from cellular metabolism to the gross breakdown of chemical compounds processed in the liver.
In a person with an enzyme deficiency, not enough of an enzyme is produced by the body. This is usually because of a genetic error where the code for producing the enzyme is not present or is distorted in some way. Symptoms of a deficiency can appear very shortly after birth, as it may lead to a variety of health problems. Patients may experience buildups of toxins in the body, declines in organ function, and other issues. Testing can reveal the presence of a compound that would be broken down by enzymes in healthy patients and doctors can also check for particular genetic markers indicative of a deficiency.
Treating patients with enzyme deficiencies is challenging. Their bodies cannot be stimulated into producing the enzyme because they lack the genetic material to do so. One option can be supplementation, in some cases, where an artificial source of the enzyme is introduced. In other instances, modifications may need to be made to the diet to avoid foods that require those enzymes to metabolize safely. Doctors can also manage symptoms like vision problems or organ failure.
The severity of an enzyme deficiency is variable, depending on the enzyme involved. In some cases, lacking key enzymes can be fatal. Other patients may experience a shortened lifespan and significant health problems as a result of not having the enzymes they need to successfully metabolize various foods. In conditions like so-called “fish odor syndrome,” the enzyme deficiency is primarily an inconvenience and is not considered life threatening or particularly dangerous to the patient's health, although it may cause discomfort.