What G6PD Stands For
G6PD stands for Glucose-6-Phosphate Dehydrogenase, an essential enzyme that protects red blood cells from oxidative damage by generating NADPH, which maintains glutathione in its reduced state. 1
Biochemical Function
- G6PD is the first enzyme of the pentose phosphate pathway, catalyzing the conversion of glucose-6-phosphate to generate NADPH 1, 2
- NADPH serves as a cofactor for glutathione reductase, converting oxidized glutathione (GSSG) to its reduced form (GSH), which is critical for detoxifying oxidative stress in red blood cells 1
- The enzyme also produces ribose 5-phosphate necessary for nucleotide synthesis 2
Structural and Genetic Characteristics
- G6PD exists as a dimer or tetramer consisting of identical subunits, with each subunit containing 515 amino acids and a molecular weight of 59,265 daltons 2
- The gene encoding G6PD is located on the X chromosome, making deficiency an X-linked recessive disorder that predominantly affects males 3, 2
- Over 250 genetic variants exist, with approximately 73 variants having identified mutations—most resulting from single or double nucleotide substitutions 2
Clinical Significance
- G6PD deficiency is the most common enzymatic disorder of red blood cells worldwide, affecting an estimated 400 million people 4, 2
- Erythrocytes are particularly vulnerable because they lack mitochondria and peroxisomes yet are hemoglobin- and iron-filled containers exposed to high oxidative stress from oxygen transport 1
- Deficiency causes red blood cells to be susceptible to hemolysis when exposed to oxidative stressors including certain medications (dapsone, primaquine, methylene blue), infections, and fava beans 1, 5, 6