Glucose-6-phosphate dehydrogenase deficiency
G6PD deficiency is an inherited disease in which the body have no enough of the enzyme glucose-6-phosphate dehydrogenase which causes premature destruction of red blood cells. G6PD is one of many enzymes that help the body process carbohydrates and turn them into energy. G6PD also protects red blood cells from potentially harmful byproducts that can accumulate when a person takes certain medications or when the body is fighting an infection.
G6PD deficiency mainly affects red blood cells, which carry oxygen from the lungs to tissues throughout the body. In people with G6PD deficiency, either the RBCs do not make enough G6PD or what is produced cannot properly function. Without enough G6PD to protect them, RBCs can be damaged or destroyed. This destruction of red blood cells is called hemolysis. Hemolytic anemia occurs when the bone marrow (the soft, spongy part of the bone that produces new blood cells) cannot compensate for this destruction by increasing its production of RBCs.
G6PD deficiency is a recessive sex-linked trait, and primarily affects men. Thus, males have only one copy of the G6PD gene, but females have two copies. Recessive genes are masked in the presence of a gene that encodes normal G6PD. Accordingly, females with one copy of the gene for G6PD deficiency are usually normal, while males with one copy have the trait.
G6PD deficiency is the most common known human enzyme disease, affecting 10% of the world's population. Glucose-6-phosphate dehydrogenase deficiency occurs most frequently in areas of the world where malaria is common, including certain parts of Africa, Asia, and the Mediterranean. It affects about 1 in 10 African-American males in the United States. G6PD deficiency can often cause hemolytic anemia, varying in severity from life-long anemia, usually after exposure to certain medications, foods, or even infections.
The disease is X-linked with about 300 variants reported, 5 classes of glucose-6-phosphatase dehydrogenase (G6PD) deficiency include low, normal, or increased levels of the enzyme.
- Severe (I) - Chronic nonspherocytic hemolytic anemia
- Severe (II) - Less than 10 percent of normal
- Moderate (III) - 10 to 60 percent of normal
- Mild to none (IV) - 60 to 150 percent of normal
- None (V) - Greater than 150 percent of normal