1. Glucose-6-phosphate Dehydration Deficiency
Nada Mohamed Ahmed ,
MD, MT (ASCP)i

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

3. HEMOLYTIC ANEMIA Hereditary Membrane defects PNH Intracorpuscular
WITHIN THE RED CELL
Extracorpuscular
OUTSIDE THE RED CELL
Hereditary
Acquired
AUTO-IMMUNE
1. Warm Ab
2. Cold Ab
3. Transfusion reactions
4. Drug associated
NON-IMMUNE
1. Hypersplenism
2. Infections (Malaria),,
3-mechanical trauma to RBCs
4. Liver dz (Spur cell)
1. Membrane defects
- Hereditary spherocytosis
- Hereditary elliptocytosis
- Hereditary pyropoikilocytosis
- Hereditary stomatocytosis
2. Enzyme defects
-G6PD
3. -Hemoglobin defects
-.Hemoglbinopathies(sickle cell disorders)
- Hb SS, CC, SC & S-B-
- Thalassemias
Membrane defects
PNH

4. Hereditary Acquired 1- Abnormalities of RBC interior a. Enzyme defects
A Simple Classification of Hemolytic Anemias
1- Abnormalities of RBC interior
a. Enzyme defects
b. Hemoglobinopathies & Thalassemia Major
2-RBC membrane abnormalities
a. Hereditary spherocytosis, elliptocytosis etc
b. Paroxysmal nocturnal hemoglobinuria
c. Spur cell anemia
3- Extrinsic factors
a. Hypersplenism
b. Antibody : immune hemolysis
c. Traumatic & Microangiopathic hemolysis
d. Infections , toxins , etc
Hereditary
Intracorpuscular
Acquired
Extracorpuscularr

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. History & Definition
It was discovered in 1950s after it was observed that some black soldiers receiving antimalarial 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
The inheritance of either of them results in this disorder.

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

8. 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)

9. G6PD Deficiency
So, an effected father will transmit the disease to all of his daughters and none of his sons. Whereas, a carrier mother will transmit the disease to half of her children. Half of her daughter will be carriers and half of her sons will be directly affected with the condition.

10. factors cause G6PD deficiency:
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

11. G6PD Deficiency Biochemistry – summary G6PD Glutathione NADP+to
NADPH
Which is responsible for
Free radicals
Which damage blood cells
G6PD
Reduces
Glutathione
Which fights
G6PD, under normal conditions, is responsible for the maintenance of Nicotinamide adenine dinucleotide phosphate (NADP+) and its conversation to NADPH. NADPH is responsible for regenerating glutathione and the removal of free radicals which cause damage to blood cells.
Free radicals are molecules that are missing an electron. Generally, free radicals attack the nearest stable molecule, "stealing" its electron. When the "attacked" molecule loses its electron, it becomes a free radical itself, beginning a chain reaction. Once the process is started, it can cascade, finally resulting in the disruption of a living cell.
Glutathione eliminates the free radical by donating the needed electron and converting the free radical into a more stable byproduct such as water (H2O).

12. 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

13. 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

14. 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

15. 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)

16. “quin” Drugs 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
“quin” Drugs
These are some of the drugs that are typically used for malaria treatment. However, they are either contraindicated in G6PD patients, high risk, possibly dose restricted, not indicated for prophylactic treatment. The biggest problem is the rapid spread of drug resistant malarial strains.

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

19. Special test
Methemoglobin reduction test

20. 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

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

22. 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)

23. Despite the name, most patients do not present this way.
What is PNH?
Paroxysmal – sudden onset
Nocturnal – occuring at night (or early in morning upon awakeneing)
Hemoglobinuria
Despite the name, most patients do not present this way.

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

25. 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.

26. . 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)