Evaluating the relationship between Clinical G6PD enzyme activity and gene variants

Glucose-6-phosphate dehydrogenase (G6PD) is a the first and rate-limiting enzyme that plays a critical role in G6PD deficiency, the most common enzyme disorder worldwide, is related to intravascular hemolysis. To determine the clinical enzyme activity level in different G6PD variants, we evaluated 15 variant from 424 clinical blood samples by using multicolor melting curve analysis and DNA sequencing. The results showed that the enzyme activities of the hemizygous deficient were 1.5-2.4 U/gHb, which was significantly lower than those of the heterozygous (P < 0.001) and the compound heterozygous variants (P < 0.05). Since the hemizygous of c.1024C > T (Chinese-5) mutation affects the kinetic parameters of G6PD and increase utilization of analogues, its enzyme activity is more than those of other mutations that mutated in the beta+alpha region of G6PD. The heterozygous enzyme levels ranged from 6.5-20.1 U/gHb; and there was no significant difference among different heterozygous variants (P > 0.05). The enzyme activity levels of the compound heterozygous mutation were mainly in the range of 1.7-3.8 U/gHb, which was much lower than that of the heterozygous mutation (P < 0.001). In summary, our findings revealed that the enzyme activity of G6PD in blood have a significant relationship with genotype of G6PD.