Table 1.
Association between genotype and phenotype. Two methods of measuring phenotype are shown: (1) by cytochemical staining, where red blood cells (RBC) are arbitrarily assigned as having high glucose-6-phosphate dehydrogenase (G6PD) activity or low G6PD activity [5] and (2) by spectrophotometric G6PD enzyme activity measurement in whole blood. The activity is described in terms of percentage of a population’s normal value [39,40].
| Genotype | Phenotype | ||
|---|---|---|---|
| % RBC with High G6PD Activity (Cytometry) | % Normal G6PD Activity (Spectrophotometry) | ||
| Males | |||
| hemizygous normal | (+) | >85% | >30% |
| hemizygous deficient | (−) | <10% | ≤30% |
| Females | |||
| homozygous normal | (+1/+1) | >85% | >70% |
| heterozygous normal | (+1/+2) | ||
| heterozygous normal/deficient | (+/−) | 10–85% | ~20–80% |
| heterozygous deficient | (−1/−2) | <10% | ≤30% |
| homozygous deficient | (−1/−1) | ||