G6PD (glucose-6-phosphate dehydrogenase) is an X-linked enzyme that catalyzes the rate-limiting step of the pentose phosphate pathway, providing essential NADPH for cellular biosynthesis and antioxidant defense 1. The enzyme protects red blood cells against oxidative damage by maintaining glutathione in its reduced state 2. G6PD deficiency is the most common human enzyme defect, affecting over 400 million people worldwide, with a geographic distribution that correlates with malaria endemicity, supporting the malaria protection hypothesis 12. Over 200 mutations have been identified, mostly single nucleotide changes causing amino acid substitutions that compromise protein stability or catalytic activity 23. Clinical manifestations include neonatal jaundice and acute hemolytic anemia triggered by oxidative stressors such as certain drugs, infections, or fava beans 45. Some variants cause chrX hemolytic anemia 1. Beyond erythrocytes, G6PD plays important roles in immune cell metabolism and cancer cell proliferation through PPP activation 67. Management focuses on avoiding known triggers, with only seven medications having solid evidence for prohibition in G6PD-deficient patients 4.