Reference levels for glucose-6-phosphate dehydrogenase enzyme activity in infants 7-90 days old in Taiwan

Background: Nationwide newborn screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency has been implemented in Taiwan since 1987 and the G6PD enzyme activity levels were applied for diagnosis confirmation. As the reference value of G6PD enzyme activity was not available for infants aged 7-90 days, this study was performed to determine the enzyme level in different genotypes. Methods: Between January 1, 2016 and June 30, 2017, 410 term infants aged 7-90 days old visiting National Taiwan University Hospital Hsinchu branch were enrolled. The comparisons of G6PD enzyme activities among genotype groups were performed. Results: G6PD enzyme activity was negatively correlated with age (R = -0.212, p = 0.01). For infants under 30 days of age, the G6PD enzyme activity levels were 1.4 +/- 0.9 U/g Hb in hemizygotes (n = 76), 6.5 +/- 2.0 U/g Hb in heterozygotes (n = 47), and 13.6 +/- 3.7 U/g Hb in those without G6PD mutations (n = 70). Among infants more than 30 days old, G6PD enzyme activity levels were 0.9 +/- 0.5 U/g Hb in hemizygotes (n = 46), 6.0 +/- 2.7 U/g Hb in heterozygotes (n = 23), and 11.7 +/- 3.4 U/g Hb in those without G6PD mutations (n = 148). G6PD levels differed significantly among the groups defined by genotypes. Conclusion: We determined G6PD enzyme activity levels in infants aged between 7 and 90 days in Taiwan. Completing the reference data and determining the cutoff values for different G6PD deficiency disease statuses will help pediatricians to make accurate diagnoses. Copyright (C) 2019, Formosan Medical Association. Published by Elsevier Taiwan LLC.