Meaning
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic disorder affecting red blood cells. It results from reduced activity of the G6PD enzyme, which plays a critical role in protecting red blood cells from oxidative damage.
It is one of the most common enzyme deficiencies worldwide.
Genetic Basis
- Caused by mutations in the G6PD gene located on the X chromosome.
- Inherited in an X-linked recessive pattern.
- Males are more commonly affected.
- Females may be carriers or, less commonly, affected if both X chromosomes carry the mutation.
Role of G6PD Enzyme
- G6PD is part of the pentose phosphate pathway.
- It helps produce NADPH (nicotinamide adenine dinucleotide phosphate).
- NADPH protects red blood cells from oxidative stress by maintaining glutathione in its reduced form.
Without adequate G6PD activity, red blood cells become vulnerable to destruction.
Clinical Features
Many individuals remain asymptomatic until exposed to oxidative stress.
Acute Hemolytic Anemia
- Sudden breakdown of red blood cells.
- Symptoms include:
- Fatigue
- Pallor
- Jaundice
- Dark urine
- Shortness of breath
Neonatal Jaundice
- Newborns may develop severe jaundice.
- In rare cases, can lead to kernicterus if untreated.
Chronic Hemolysis
- Rare but may occur in severe variants.
Triggers of Hemolysis
Certain substances can precipitate hemolysis in affected individuals:
Drugs
- Antimalarials such as primaquine
- Sulfonamides
- Certain antibiotics
Foods
- Fava beans (favism)
Infections
- Bacterial or viral infections can increase oxidative stress.
Diagnosis
- Blood test measuring G6PD enzyme activity.
- Peripheral blood smear may show hemolytic changes.
- Testing should ideally be done after recovery from an acute episode to avoid false-normal results.
Management
- Avoidance of known triggers.
- Supportive care during hemolytic episodes.
- Blood transfusion in severe cases.
- Phototherapy or exchange transfusion in neonatal jaundice if required.
There is no definitive cure, as it is a genetic condition.
Public Health Significance
- Common in Africa, the Mediterranean region, the Middle East, and parts of South Asia.
- Prevalence is linked to historical protection against severe malaria.
- Screening is important before prescribing certain medications, particularly antimalarials.
Conclusion
G6PD deficiency is a hereditary enzymatic disorder that predisposes individuals to hemolytic anemia under oxidative stress. Early identification and avoidance of triggers are central to effective management and prevention of complications.
