G6PD Deficiency (cont.)
What genes are related to glucose-6-phosphate dehydrogenase deficiency?
Mutations in the G6PD gene cause glucose-6-phosphate dehydrogenase
deficiency.
The G6PD gene provides instructions for making an enzyme called
glucose-6-phosphate dehydrogenase. This enzyme is involved in the normal
processing of carbohydrates. It also protects red blood cells from the effects
of potentially harmful molecules called reactive oxygen species. Reactive oxygen
species are byproducts of normal cellular functions. Chemical reactions
involving glucose-6-phosphate dehydrogenase produce compounds that prevent
reactive oxygen species from building up to toxic levels within red blood cells.
If mutations in the G6PD gene reduce the amount of glucose-6-phosphate
dehydrogenase or alter its structure, this enzyme can no longer play its
protective role. As a result, reactive oxygen species can accumulate and damage
red blood cells. Factors such as infections, certain drugs, or ingesting fava
beans can increase the levels of reactive oxygen species, causing red blood
cells to be destroyed faster than the body can replace them. A reduction in the
amount of red blood cells causes the signs and symptoms of hemolytic anemia.
Researchers believe that carriers of a G6PD mutation may be partially
protected against malaria, an infectious disease carried by a certain type of
mosquito. A reduction in the amount of functional glucose-6-dehydrogenase
appears to make it more difficult for this parasite to invade red blood cells.
Glucose-6-phosphate dehydrogenase deficiency occurs most frequently in areas of
the world where malaria is common.
How do people inherit glucose-6-phosphate dehydrogenase deficiency?
This condition is inherited in an X-linked recessive pattern. The gene
associated with this condition is located on the X chromosome, which is
one of the two sex chromosomes. In males (who have only one X chromosome), one
altered copy of the gene in each cell is sufficient to cause the condition. In females
(who have two X chromosomes), a mutation would have to occur in both copies of
the gene to cause the disorder. Because it is unlikely that females will have
two altered copies of this gene, males are affected by X-linked recessive
disorders much more frequently than females. A striking characteristic of
X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
What other names do people use for glucose-6-phosphate dehydrogenase deficiency?
- Deficiency of glucose-6-phosphate dehydrogenase
- G6PDD
- G6PD Deficiency
SOURCE: Genetics Home Reference. Glucose-6-phosphate dehydrogenase deficiency.
Last Editorial Review: 7/9/2009
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