Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common enzyme deficiency in Taiwan with incidence of 1.8-2.1%. Nationwide newborn screen has been implemented since 1987. To assess the lacking reference levels of G6PD enzyme activity between 7 to 90 days old infants, infants visited National Taiwan University Hospital Hsin-chu Branch from January 1, 2016 to June 30, 2017 were enrolled. G6PD mutation genotyping were carried out by using the Agena MassARRAY system (Agena, San Diego, CA), containing 21 mutations: c.95A>G, c.371A>G, c.392G>T, c.487G>A, c.493A>G, c.517T>C, c.519C>G, c.519C>T, c.592C>T, c.835A>T, c.835A>G, c.871G>A, c.1004C>A, c.1004C>T, c.1024C>T, c.1311C>T, c.1360C>T, c.1376G>T, c.1387C>T, c.1388G>A and c.1365-13T>C.

Total 448 cases were studied. Assuming the newborn screen and gene mutation reports are compatible, 24 cases with mismatch reports were excluded. Finally, 424 cases were enrolled, 60.6% (n = 257) were males. The mean age was 37.9 ± 25.0 days old, and mean gestational age was 38 weeks and 6 days. Total 236 cases passed newborn screen and no gene mutation was found. Eighteen (20.5%) samples were collected while infants presented jaundice and the levels were significantly higher than those without jaundice (16.3 ± 4.9 vs. 13.6 ± 3.7 U/gHb, p= 0.014). Therefore, the cases with jaundice were excluded. The rest 218 cases were analyzed and the reference levels of G6PD enzyme activity were 13.6 ± 3.7 U/gHb (95% confidence interval 7.3-25.0 U/gHb), 12.2 ± 3.8 U/gHb (95% confidence interval 8.0-25.2 U/gHb) and 11.4 ± 3.0 U/gHb (95% confidence interval 7.5-19.3 U/gHb) for infants of age 7-30 days old (n = 70), 31-60 days old (n = 65), and 61-90 days old (n = 83), respectively (Table 1). There was no difference between males and females.

Total 188 cases failed newborn screen and gene mutation was detected simultaneously. All cases harbored only 1 mutation. The 3 most common mutations, including c.1376G>T (p.R459L), c.1388G>A (p.R463H) and c.95A>G (p.H32R) represented 80.8% (n = 152) in our study. The G6PD level of deficiency cases was significantly lower than that of carrier (Table 2). In G6PD deficiency cases, the G6PD enzyme activity level of cases with c.1388G>A mutation presented the lowest level (p= 0.01). Otherwise, in G6PD carrier cases, the level of cases with c.95A>G mutation tended to present the lowest level (p= 0.056).

In conclusion, the levels of G6PD enzyme activity were inversely corrected to age. From our results, we set up the reference levels of G6PD enzyme activity in infants of age between 7 to 90 days old, making diagnosis of G6PD deficiency more precisely in Taiwan.

Disclosures

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.

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