G6PD

Biochem lec prefinal

What is G6PD deficiency

An inherited enzyme deficiency (Favsim) that causes RBCs to breakdown (hemolysis), most common enzyme deficiency anemia worldwide

G6PD stands for

Glucose 6 phospate dehydrogenase

Do most affect people show symptoms

No, most people are asymptomatic until triggered

How common is G6PD deficiency worldwide

Affects more than 400 million people, most common human enzyme defect

Why is it more common in men

X-linked inheritance (men have only one X chromosome) or autosomal recessive manner

Where is it most prevalent?

Tropical and subtropical areas (Africa, Mediterranean, Asian)

How is G6PD linked to malaria?

Provides some protection against uncomplicated malaria, but not severe malaria

What genetic mutation causes G6PD deficiency

Mutations in the G6PD gene on the X chromosome

What happens when RBCs lack G6PD enzyme

They cannont handle oxidative stress → hemolysis when exposed to triggers

Hemolysis

the destruction of red blood cells

Common triggers of hemolysis in G6PD

Fava beans, infections, certain drugs (antimalarials, sulfa drugs, aspirin, some antibiotics)

Why are RBCs more fragile in G6PD deficiency

They are highly susceptible to oxidative stress, leading to premature breakdown

What events can cause oxidative stress in RBCs

Fever, viral/ bacterial infections, DKA, oxidative drugs, and fava beans

What are Heinz bodies

Inclusions of denatured hemoglobin seen in G6PD deficiency

What are bite cells?

RBCs with peices “bitten out” by the spleen after Heinz body removal

Key signs and symptoms of a hemolytic episode in G6PD deficiency

Jaundice, dark urine, fatigue, pallor, SOB, tachycardia, abdominal/ back pain, splenomegaly, neonatal jaundice, fever, dizziness/ confusion

What blood test findings suggest G6PD deficiency

Anemia, jaundice, reticulocytosis, bite cells, blister cells, Heinz bodies

Why can G6PD tests give false negatives after a hemolytic episode

older deficient RBCs are destroyed, leaving younger reticulocytes rich in G6PD

When should testing for G6PD deficiency be repeated

Several weeks after an acute hemolytic episode

When is screening recommended

In high-risk populations, neonatal jaundice, unexplained hemolytic anemia, before giving certain drugs, and in family member

What is the main treatment for G6PD deficiency

Avoiding triggers (fava beans, oxidative drugs, infections)

Can stress cause hemolysis in G6PD deficiency

Yes, emotional stress and chemical exposures can trigger episodes

how severe are symptoms in G6PD deficiency

Varies by genetic variant and level of enzyme activity

Do all patient with G6PD deficiency need treatment

No, many remain asymptomatic