Glucose-6-phosphate dehydrogenase deficiency

Alternative names:

anemia - hemolytic due to G6PD deficiency; G-6-PD deficiency; hemolytic anemia due to G6PD deficiency

Definition:

A hereditary, sex-linked, enzyme defect that results in the breakdown of red blood cells when the person is exposed to the stress of infection or certain drugs.

Causes, incidence, and risk factors:

G-6-PD deficiency is an inheritable x-linked recessive disorder whose primary effect is the reduction of G-6-PD in the red blood cell, with resultant hemolysis of the cell. The ultimate effect of the disease is to produce anemia, either acute hemolytic or a chronic spherocytic type.

In the United States, the incidence of G-6-PD is much higher among the Black American population with a heterozygote frequency (carrier state with one normal gene and one abnormal gene) of 24%. Approximately 10 to 14% of the black American male population is affected. The disorder may occasionally affect a few black females to a mild degree (depending on their genetic inheritance). People with the disorder are not normally anemic and display no evidence of the disease until the red cells are exposed to an oxidant or stress.

Drugs that can precipitate this reaction include:

• antimalarial agents
• sulfonamides (antibiotic)
• aspirin
• nonsteroidal antiinflammatory drugs (NSAIDs)
• nitrofurantoin
• quinidine
• quinine
• others

Also:

• exposure to certain chemicals such as those in mothballs

The chronic spherocytic anemia is unaffected by exposure to these drugs.

The risk of acute hemolytic crisis can be decreased by reviewing the family history for any evidence of hemolytic anemias or spherocytosis or testing before giving any medications belonging to the above class of chemicals.

The episodes are usually brief, because newly produced (young) red cells have normal G6PD activity.

Risk factors are being of the black race, being male, or having a family history of G6PD deficiency. Another type of this disorder can occur in whites who originated in the Mediterranean basin. It, too, is associated with acute episodes of hemolysis. Episodes are longer and more severe than the other type of disorders.