Table 1.
Classification of G6PD variants
| World Health Organization class | Enzyme activity | Associated phenotype | Variant example | Genotyping reference |
|---|---|---|---|---|
| I | Severe deficiency | Congenital nonspherocytic hemolytic anemia (CNSHA) | Tondela | [36] |
| Palermo | [37] | |||
| II | < 10% severely deficient | Risk of acute hemolytic anemia | Mediterranean | [38] |
| Canton | [39,40] | |||
| III | 10–60% Moderate deficiency | Risk of acute hemolytic anemia | A- Haplotype | [41,42] |
| Asahi | [42] | |||
| IV | 60–150% Normal activity | No clinical manifestations | B (wild type) | |
| A | [43] | |||
| V | > 150% Enhanced activity | – | Hektoen | [44,45] |