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Glucose-6-phosphate dehydrogenase deficiency
Definition
Glucose-6-phosphate dehydrogenase deficiency is
an X-linked recessive hereditary disease affecting males and carrier by females
characterised by abnormally low levels of the
glucose-6-phosphate dehydrogenase enzyme (abbreviated G6PD or G6PDH).
It is a metabolic enzyme involved in the pentose phosphate pathway,
especially important in red blood cell metabolism.
it's the only source of NADPH in red blood cells
NADPH needed for the production of reduced glutathion a
deficiency render the red cells susceptible to oxidant stress
see the image that i put to understand
Individuals with the disease may exhibit nonimmune hemolytic
anemia in response to a number of causes.
It is closely linked to favism, a disorder characterized by a hemolytic reaction to consumption of broad beans, with a name derived from the Italian name of the broad bean (fava). Sometimes the name, favism, is alternatively used to refer to the enzyme deficiency as a whole
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Alternative Names
G-6-PD deficiency; Hemolytic anemia due to G6PD deficiency; Anemia - hemolytic due to G6PD deficiency
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Causes
The primary effect of G-6-PD deficiency is the reduction of the
enzyme G-6-PD in red blood cells, causing destruction of the cells (hemolysis).
Ultimately, this hemolysis leads to anemia -- either acute or chronic.
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Symptoms
Dark urine
Enlarged spleen
Fatigue
Paleness
Rapid heart rate
Shortness of breath
Yellow skin color (jaundice)
Note: Severe hemolysis may cause hemoglobinuria
(hemoglobin in the urine
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Exams and Tests
Anemia
Hemolysis
Increase in the number of young red blood cells
in circulation, following a hemolytic crisis
Reduced G-6-PD activity
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Tests may find:
Elevated absolute reticulocyte count
Elevated bilirubin levels
Elevated serum LDH
Heinz bodies present
on examination of the peripheral blood smear using special stains
blood film may show contracted and fragmented
cells Bite cells and Blister cells
Hemoglobin in the urine
Low red blood cell count and hemoglobin levels
low serum haptoglobin
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Additional tests may include:
Methemoglobin reduction test
Methylene blue test
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Treatment
If the cause of a hemolytic crisis is an infection, it should be treated.
If the cause is a drug, the drug should be stopped.
People with the Mediterranean form, or those in hemolytic crisis,
may occasionally require transfusions.
referance: web sites and Essential Hematology Book
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