Glucose-6-phosphate Dehydrogenase Deficiency - Classification

Classification

The World Health Organization classifies G6PD genetic variants into five classes, the first three of which are deficiency states.

1. Severe deficiency (<10% activity) with chronic (nonspherocytic) hemolytic anemia
2. Severe deficiency (<10% activity), with intermittent hemolysis
3. Mild deficiency (10-60% activity), hemolysis with stressors only
4. Non-deficient variant, no clinical sequelae
5. Increased enzyme activity, no clinical sequelae