1. Glucose-6-phosphate dehydration deficiency, also known as G6PD deficiency, results from a lack of the G6PD enzyme which generates NADPH to fight oxidative stress and protect red blood cells. 2. Those with G6PD deficiency typically do not show symptoms until exposed to oxidative stresses like certain drugs, infections, or foods, which can cause their red blood cells to rupture and hemolyze. 3. Diagnosis involves testing for G6PD enzyme levels or mutations, with clues seen on blood smears like bite cells or Heinz bodies from hemoglobin denaturation. Management focuses on avoiding triggers and treating any acute hemolytic episodes.

1. Glucose-6-phosphate
Dehydration Deficiency

3. Objectives
• Introduction
• Definition
• Factors cause G6PD deficiency
• Pathophysiology (mechanism)
• Symptoms
• Lab findings

4. Hexose monophosphate pathway
• Also called pentose phosphate pathway ‘PPP’.
• About 5% of glycolysis occurs by this pathway.
• In which:

5. Introduction
• FUNCTION OF G6PD
• Regenerates NADPH, allowing regeneration of
glutathione
• Protects against oxidative stress
• Lack of G6PD leads to hemolysis during
oxidative stress- infection, medication, fava
beans
• Oxidative stress leads to Heinz body
formation, extravascular hemolysis

6. • Pentose pathway also called the
phosphogluconate pathway and the hexose
monophosphate shunt is a process that
generates NADPH and pentoses (5-carbon
sugar)
OHHHWW MAAI GAAD!!!!
PENTOSE PATHWAY?????
(Oxidised form)
(Reduced form)

7. History & Definition
• It was discovered in 1950s after it was
observed that some
receiving antimalarial
black soldiers
drug primaquine
developed hemolytic anemia.
• It is the most common red cell
enzymopathy associated with hemolysis.
• Large no. of abnormal genes code for the
G6PD

8. Definition
• X-linked disease , sesult in G6PD
Deficiency (RBCs enzym deficiency )
asymptomatic unless Oxidative stress
causes the RBC’s to break apart.
• Inherited –, Recessive

9. Genetics
• The G6PD gene is located on the X
chromosome
• Thus the deficiency state is a sex-linked trait
• Affected males inherit the abnormal gene
from their mothers who are usually carriers
(heterozygotes)

11. G6PD Deficiency

12. G6PD variants
• There are over 400 variants of the G6PD enzyme:
• G6PD A and G6PD B are the well known variants.
❖G6PD B: The normal G6PD enzyme.
❖G6PD A: found with normal enzyme activity but
differ from B by a single amino acid substitution,
resulting in a different in electrophoretic
mobility.

13. G6PD variants
❖G6PD A : the common one associated with
haemolysis, electrophoretically identical to A
but has only 5- 15% of the normal enzymatic
activity.
❖Mediterranean G6PD: electrophoretically
identical to B but its activity is often 1% less
than normal.

14. World Health Organization classifies
for G6PD genetic variants
• Class I: Severe deficiency (<10% activity) with
chronic (nonspherocytic) hemolytic anemia
• Class II: Severe deficiency (<10% activity),
with intermittent hemolysis
• Class III: Mild deficiency (10-60% activity),
hemolysis with stressors only

15. • Class IV: Non-deficient variant, no
clinical sequelae
• Class V: Increased enzyme activity, no
clinical sequelae
World Health Organization classifies
for G6PD genetic variants

16. • Individuals who have inherited one of the many G6PD mutations do not show
clinical manifestation.
• Some of patients with G6PD develop hemolytic anemia if they are exposed or
ingest any of the followings oxidizing agents:
1-Oxidant drugs: Remember “AAA”?
Antibiotics : e.g. sulfamethoxazole
Antimalarias : e.g. primaquine
Antipyretics : e.g. acetanilid
2- Favism:
The hemolytic effect of ingesting of fava beans is not observed in all
individuals with G6PD deficiency but all patients with favism have G6PD
deficiency
factors cause G6PD deficiency:

17. G6PD Deficiency
• Biochemistry – summary
• G6PD
Reduces
Which is
responsible for
• NADP+
• to
• NADPH
• Glutathione
Which fights
Which damage
blood cells
• Free radicals

18. Pathophysiology
• Oxidative denaturation of hemoglobin is the
major cause of H. A in G6PD deficiency
• It is important in the conversion of glucose-6-
P to phosphogluconate
• For subsequent production of NADPH &
reduced glutathione (GSH)
• GSH protects enzymes & hemoglobin against
oxidation by reducing H2O2 & free radicals

19. Pathophysiology
• H2O2 is generated normally in small amounts
during normal red cell metabolism
• Larger amounts produced when an oxidant
drug interacts with oxyhemoglobin
• Normal red cells have sufficient G6PD
activity to maintain adequate GSH levels
• When deficient, red cells fail to produces
sufficient G6PD to detoxify peroxide

20. Pathophysiology
• Hb is then oxidized to Hi, heme is
liberated from globin & globin denatures
producing Heinz bodies
• Heinz bodies attach to membrane
sulfhydryl groups inducing cell rigidity
• At this point red cells can no longer
traverse the splenic microcirculation
• Hence lysis occurs

21. Symptoms
• Persons with this condition do not display any signs of
the disease until their red blood cells are exposed to
certain chemicals in food or medicine, or to stress.
Symptoms are more common in men and may include:
Dark urine
Enlarged spleen
Fatigue
Pallor
Rapid heart rate
Shortness of breath
Yellow skin color (jaundice)
•
•
•
•
•
•
•
•

22. G6PD Deficiency
• Malaria Treatment
– chloroquine
– atovaquone-proguanil (Malarone®)
– artemether-lumefantrine (Coartem®)
– mefloquine (Lariam®)
– quinine
– quinidine
– doxycycline (used in combination with quinine)
– clindamycin (used in combination with quinine)
– primaquine

23. Diagnosis of
G6PD Deficiency Hemolytic Anemia
1-CBC
Bite cells, blister cells, irregular small
cells, Heinz bodies, polychromasia
G-6-PD level
Bite” cells
Spleen removes portion of RBC that had Heinz
body, preventing intravascular hemolysis
• 2-Screening:
• Qualitative assessment of G6PD enzymatic activity
(UV-based test)

24. Diagnosis of
G6PD Deficiency Hemolytic Anemia
• 3-Confirmatory test:
• Quantitative measurement of G6PD
enzymatic activity
4-Molecular test:
• Detection of G6PD gene mutation

27. Special test
• Methemoglobin reduction test

28. Methemoglobin Reduction Test
• Sodium nitrite converts Hb (hemoglobin)
to Hi (methemoglobin)
• Adding methylene blue should stimulate
the pentose phosphate pathway,
reducing methemoglobin
• In G6PD Deficiency, methemoglobin
persists

29. Methemoglobin Reduction Test
• Normal blood → clear red color
• Deficient blood → brown color
• Deficient blood
Normal blood

30. Clinical Manifestations
• The patient may experience an acute
hemolytic crisis within hours of exposure to
the oxidant stress
• Hemolytic crisis is self-limited even if the
exposure continues &
• Only older cell population is rapidly destroyed
• A minority of patients are sensitive to
exposure to fava beans (favism phenomenon)

31. What is PNH?
• Paroxysmal –
sudden onset
• Nocturnal –
occuring at night
(or early in morning
upon awakeneing)
• Hemoglobinuria

32. What is PNH?
• A rare and unusual acquired hematologic disorder
characterized by
– Intravascular hemolysis
– Bone marrow failure (cytopenias)
– Thrombosis.

33. What is PNH?
• Intravascular RBCs break down result
from Complement activation due to
absence of CD55, CD59
Symptoms
- passage of dark brown urine in the
morning.

34. . PNH –laboratory features:
- pancytopenia
- chronic urinary iron loss
- serum iron concentration decreased
- hemoglobinuria
- hemosiderinuria
- positive Ham’s test (acid hemolysis test)
- positive sugar-water test
- specific immunophenotype of erytrocytes
(CD59, CD55)