An enzyme is a protein that speeds up the rate at which a chemical reaction occurs. Enzymes are substrate specific, meaning that each type of enzyme has a specific type of molecule that it affects. The human body needs enzymes to influence the rates at which biological processes occur. A number of diseases occur due to insufficient quantities of specific enzymes.
Of all known enzyme deficiencies in humans, glucose-6-phosphate dehydrogenase, or G6PD, deficiency is the most common throughout the world. A deficiency of G6PD can be inherited and is most frequently seen in those of African, Asian, Mediterranean or Middle-Eastern descent.
African-American men are the demographic most commonly deficient in G6PD in the United States. Without enough G6PD, red blood cells are more vulnerable to breaking down, and hemolytic anemia can result. Those with this deficiency may not show any symptoms, or they can experience anemia with back pain, abdominal pain or jaundice when exposed to stressors such as infection.
Congenital Adrenal Hyperplasia
Another inherited disorder, congenital adrenal hyperplasia, is the most common adrenal disorder among infants and children. This condition results from a deficiency of the enzyme that enables the adrenal glands to produce adequate quantities of cortisol. The body responds by stimulating the adrenal glands in an attempt to prompt cortisol production. As a result, the adrenal glands enlarge and produce more cortisol, as well as hormones that cause the body to reabsorb water and sodium, and other hormones that influence male sexual characteristics. An excess of male hormones can result.
Gaucher's disease is an inherited deficiency of the enzyme glucocerebrosidase. Without adequate amounts of this enzyme, a fatty substance called glucocerebroside accumulates in the internal organs, including the brain. Enzyme replacement therapy may help to reduce the skeletal anomalies and abnormal blood counts associated with certain types of this disorder.
Pyruvate Kinase Deficiency
An inherited deficiency of the enzyme pyruvate kinase causes red blood cells to break down, resulting in anemia. After G6PD deficiency, it is the second most common enzyme-related defect that can cause red blood cells to break down. Unlike G6PD deficiency, pyruvate kinase deficiency is present across all ethnic backgrounds. Symptoms of this deficiency include anemia, jaundice and lethargy.