G-6-PD deficiency is 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.

Alternative Names

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

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.

Signs and tests

Anemia

Hemolysis

Reduced G-6-PD activity

Reticulocytosis following a

hemolytic crisis Tests include:

Elevated

bilirubin levels

Elevated serum LDH

Low

serum haptoglobin

Hemoglobin

in the urine

Elevated absolute

reticulocyte count

Low

red blood cell count and hemoglobin

Heinz bodies present on examination of the

peripheral blood smear using special stains

Methylene blue test

Methemoglobin reduction

test

Treatment

If the cause is an infection, it should be treated. If the cause is a drug, the offending agent should be stopped. People with the Mediterranean form, or those in hemolytic crisis may occasionally require transfusions.

Expectations (prognosis)

Spontaneous recovery from hemolytic crises is the usual outcome.

Complications

Rarely, kidney failure or death may occur following a severe hemolytic event.

Calling your health care provider

Call for an appointment with your health care provider if symptoms of hemolytic anemia due to G-6-PD deficiency develop. Call your health care provider if you have G-6-PD deficiency and symptoms of hemolytic anemia do not disappear after treatment of the cause.

Prevention

People with G-6-PD must strictly avoid factors that can precipitate an episode, especially drugs known to cause oxidative reactions. Genetic counseling or genetic information may be of interest to heterozygous women and affected men.