Fig. 1

The common variants and classification in the G6PD gene. The G6PD gene variants are classified into Class I to Class IV based on the genotype and clinical manifestations (WHO classification). Red color indicates a Class I severe enzyme deficiency with chronic non-spherocytic hemolytic anemia (CNSHA). Blue color indicates a Class II severe enzyme deficiency with less than 10% of the normal activity. Orange color indicates a Class III mild to a moderate enzyme deficiency (10 to 60% of normal activity). Black color indicates a Class IV very mild or almost normal enzyme activity (> 60% normal activity and no clinical problem). Data from G6PD gene variant database (http://www.bioinf.org.uk)