Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency

X-linked recessive disorder resulting in reduced half life of G6PD; Most common in people of African or Mediterranean descent (malaria-endemic areas); Deficiency of G6PD leads to a sensitivity of RBCs to oxidative stress due to lack of reduced glutathione; Hemolysis precipitated by oxidative stress caused by drugs (sulfonamides, dapsone, nitrofurantoin, primaquine, doxorubicin), infection, DKA, foods (fava beans).

Two variants:-
1. African variant:- mildly reduced half-life of G6PD leading to mild intravascular hemolysis
with oxidative stress.
2. Mediterranean variant:- markedly reduced half-life of G6PD leading to marked intravascular
hemolysis with oxidative stress.

Diagnosis:-

1. PBS shows Heinz bodies (abnormal hemoglobin precipitates within RBCs) and Bite cells
(due to phagocytosis of Heinz bodies from splenic macrophages results in bite cells).
2. ↓ G6PD levels (may be normal after acute hemolysis because older RBCs have already lysed
and young RBCs may still have near-normal levels), hence performed weeks after hemolytic
episode resolves.
3. Laboratory findings are decreased Hb, increased reticulocytes, increased indirect bilirubin, increased
LDH, and decreased haptoglobin.

Clinical features:-

1. Episodic hemolytic anemia precipitated by oxidative stress mentioned above.
2. Dark urine, jaundice and splenomegaly on examination.

Treatment:

1. Stop the precipitating agents.
2. Maintain hydration and blood transfusion in acute hemolytic reactions.
3. Iron and folic acid supplementation (to support erythropoiesis).