Glucose-6-phosphate dehydrogenase activity in male premature and term neonates

Retinopathy of Prematurity and Glucose-6-Phosphate Dehydrogenase Activity: A Case-Control Study

OBJECTIVE

To determine whether red blood cell glucose-6-phosphate dehydrogenase (G6PD) activity is associated with retinopathy of prematurity (ROP).

METHODS

This case-control study was conducted in a Level-3 neonatal unit. Subjects were inborn boys with birth weight <2000 g. "Cases" were consecutive subjects with ROP of any severity. "Controls" were consecutive unrelated subjects without ROP. Recipients of blood or exchange transfusions were excluded. Sixty cases (out of 98 screened) and 60 controls (out of 93 screened) were enrolled. G6PD activity (quantitative assay) as the candidate risk factor was evaluated.

RESULTS

Sixty cases with 60 controls [mean (SD) gestation 28.80 (2.2) and 30.60 (2.2) wk respectively] were compared. "Cases" had a higher median (1st, 3rd quartile) G6PD activity compared to "controls" [7.39 (4.7, 11.5) vs. 6.28 (4.2, 8.8) U/g Hb, p = 0.084]. G6PD activity was highest among ROP requiring treatment [8.68 (4.7, 12.3)] followed by ROP not requiring treatment [6.91 (4.4, 11.0)], followed by controls (plinear trend = 0.06). Gestation, birth weight, duration of oxygen, breastmilk feeding, and clinical sepsis were other variables associated with ROP on univariable analysis. On multivariable logistic regression, G6PD activity [Adjusted OR 1.14 (1.03, 1.25), p = 0.01] and gestation [Adjusted OR 0.74 (0.56, 0.97), p = 0.03] independently predicted ROP. C-statistic of the model was 0.76 (95% CI 0.67, 0.85).

CONCLUSIONS

Higher G6PD activity was independently associated with ROP after adjusting for confounders. Each 1 U/g Hb increase in G6PD increased the odds of ROP by 14%. Severer forms of ROP were associated with higher levels of G6PD activity.

Optimizing Measurement and Interpretation of the G6PD/Hb Ratio

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD)/hemoglobin (Hb) ratio helps detect G6PD deficiency, an X-linked disorder that can be asymptomatic or cause acute hemolytic anemia and chronic hemolysis. We investigated preanalytical, analytical, and postanalytical aspects to optimize G6PD/Hb measurement and interpretation.

METHODS

G6PD was measured with the Pointe Scientific assay and Hb with Drabkin's reagent on Alinity c® (Abbott Diagnostics). Stability of G6PD/Hb was assessed after 7 and 14 days while stored at 2-8 °C. Stability of hemolysate prepared for G6PD analysis was assessed using QC and patient samples up to 4 h at room temperature or 2-8 °C. Analytical performance specifications including precision, method comparison, linearity, LOQ, and carry-over were established for the enzymatic reaction of G6PD and spectrophotometric reading of Hb. G6PD/Hb reference interval and cut-offs were established indirectly using truncated maximum likelihood method (TML) using retrospective data (n = 4715 patient data points).

RESULTS

Samples were stable after 7 days at 2-8°C, unless grossly hemolyzed. Hemolysate prepared for G6PD measurement remained stable for up to 4 h for QC at room temperature and 2-8°C, but up to 30 min-1 h at room temperature and 1-2 h at 2-8 °C for patient samples. Precision, linearity, LOQ, and carryover were acceptable. G6PD/Hb cut-offs were <3.3, ≥3.3, 3.3-8.9, and ≥8.9 U/g Hb for deficient males/females, normal males, intermediate females, and normal females, respectively.

CONCLUSIONS

In vitro hemolysis and delayed hemolysate analysis significantly reduce G6PD/Hb stability. QC material cannot detect the impact of delayed hemolysate analysis. These findings were foundational for optimizing G6PD/Hb protocols for a new platform and establishing laboratory-specific G6PD/Hb cut-offs.

[Screening results and genetic features of glucose-6-phosphate dehydrogenase deficiency in 54 025 preterm infants in Chengdu, China]

OBJECTIVE

To analyze the screening results of glucose-6-phosphate dehydrogenase (G6PD) deficiency and gene mutation distribution of G6PD deficiency in preterm infants in Chengdu, China, in order to provide a basis for the improvement of G6PD screening process in preterm infants.

METHODS

Fluorescent spot test for G6PD deficiency using dried blood spots was used for G6PD screening of 54 025 preterm infants born from January 1, 2015 to December 31, 2019 in Chengdu, and G6PD enzymology and gene detection were used for the diagnosis of 213 infants with positive screening results.

RESULTS

Among the 54 025 preterm infants, 192 were diagnosed with G6PD deficiency, with an incidence rate of 3.55‰. The incidence rate of G6PD deficiency in preterm infants was higher than that in full-term infants in the same period of time and tended to increase year by year. Birth in summer, gestational age <32 weeks, and birth weight <2 500 g were influencing factors for the increase in false positive rate of screening (P < 0.05). The diagnostic accordance rate of genetic tests was significantly higher than that of enzyme activity assay in female infants (P < 0.05). Nine gene mutations were detected in Chengdu, without compound heterozygous mutation. Homozygous mutation was not detected in female infants. In the 80 infants with gene mutations, the top three gene mutations were c.1388G>A in 26 infants (32%), c.1376G>T in 21 infants (26%), and c.1024C>T in 13 infants (16%), accounting for 75%. There was a significant difference in pathogenicity grading among the three gene mutations (P < 0.001). The pairwise comparison showed that c.1024C>T had a significantly lower pathogenicity grade than c.1376G>T and c.1388G>A (P < 0.0167), suggesting that c.1376G>T and c.1388G>A had greater influence on enzyme activity than c.1024C>T.

CONCLUSIONS

Screening for G6PD deficiency in preterm infants should be taken seriously. It is recommended to apply cold-chain transportation of samples in summer to reduce the false positive rate of primary screening for G6PD deficiency. Genetic tests should be promoted in girls with positive screening results to improve the detection rate of G6PD deficiency in preterm female infants. There are various types of gene mutations in preterm infants with G6PD deficiency in Chengdu, and infants with c.1024C>T mutation tend to have mild conditions.

Glucose 6 phosphatase dehydrogenase (G6PD) and neurodegenerative disorders: Mapping diagnostic and therapeutic opportunities

Glucose 6 phosphate dehydrogenase (G6PD) is a key and rate limiting enzyme in the pentose phosphate pathway (PPP). The physiological significance of enzyme is providing reduced energy to specific cells like erythrocyte by maintaining co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH). There are preponderance research findings that demonstrate the enzyme (G6PD) role in the energy balance, and it is associated with blood-related diseases and disorders, primarily the anemia resulted from G6PD deficiency. The X-linked genetic deficiency of G6PD and associated non-immune hemolytic anemia have been studied widely across the globe. Recent advancement in biology, more precisely neuroscience has revealed that G6PD is centrally involved in many neurological and neurodegenerative disorders. The neuroprotective role of the enzyme (G6PD) has also been established, as well as the potential of G6PD in oxidative damage and the Reactive Oxygen Species (ROS) produced in cerebral ischemia. Though G6PD deficiency remains a global health issue, however, a paradigm shift in research focusing the potential of the enzyme in neurological and neurodegenerative disorders will surely open a new avenue in diagnostics and enzyme therapeutics. Here, in this study, more emphasis was made on exploring the role of G6PD in neurological and inflammatory disorders as well as non-immune hemolytic anemia, thus providing diagnostic and therapeutic opportunities.

Barriers to routine G6PD testing prior to treatment with primaquine

BACKGROUND

Primaquine is essential for the radical cure of vivax malaria, however its broad application is hindered by the risk of drug-induced haemolysis in individuals with glucose-6-phosphate-dehydrogenase (G6PD) deficiency. Rapid diagnostic tests capable of diagnosing G6PD deficiency are now available, but these are not used widely.

METHODS

A series of qualitative interviews were conducted with policy makers and healthcare providers in four vivax-endemic countries. Routine G6PD testing is not part of current policy in Bangladesh, Cambodia or China, but it is in Malaysia. The interviews were analysed with regard to respondents perceptions of vivax malaria, -primaquine based treatment for malaria and the complexities of G6PD deficiency.

RESULTS

Three barriers to the roll-out of routine G6PD testing were identified in all sites: (a) a perceived low risk of drug-induced haemolysis; (b) the perception that vivax malaria was benign and accordingly treatment with primaquine was not regarded as a priority; and, (c) the additional costs of introducing routine testing. In Malaysia, respondents considered the current test and treat algorithm suitable and the need for an alternative approach was only considered relevant in highly mobile and hard to reach populations.

CONCLUSIONS

Greater efforts are needed to increase awareness of the benefits of the radical cure of Plasmodium vivax and this should be supported by economic analyses exploring the cost effectiveness of routine G6PD testing.

The Preterm Infant: A High-Risk Situation for Neonatal Hyperbilirubinemia Due to Glucose-6-Phosphate Dehydrogenase Deficiency

Prematurity and glucose-6-phosphate dehydrogenase (G6PD) deficiency are risk factors for neonatal hyperbilirubinemia. The 2 conditions may interact additively or synergistically, contributing to extreme hyperbilirubinemia, with the potential for bilirubin neurotoxicity. This hyperbilirubinemia is the result of sudden, unpredictable, and acute episodes of hemolysis in combination with immaturity of bilirubin elimination, primarily of conjugation. Avoidance of contact with known triggers of hemolysis in G6PD-deficient individuals will prevent some, but not all, episodes of hemolysis. All preterm infants with G6PD deficiency should be vigilantly observed for the development of jaundice both in hospital and after discharge home.

National G6PD neonatal screening program in Gaza Strip of Palestine: rationale, challenges and recommendations

Congenital genetic disorders affecting neonates or young children can have serious clinical consequences if undiagnosed and left untreated. Early detection and an accurate diagnosis are, therefore, of major importance for preventing negative patient outcomes. Even though the occurrence of each specific metabolic disorder may be rare, their collective impact of preventable complications may be of considerable importance to the public health. Our previous studies showed that glucose-6-phosphate dehydrogenase (G6PD) deficiency is a problem of public health importance that has been shown to be a predominant cause of acute hemolytic anemia requiring hospitalization in Palestinian young children in Gaza Strip. Intriguingly, the majority of these children had one of the three variants, Mediterranean(c.) (563T) , African G6PD A-(c.) (202A) (/c.) (376G) and heretofore unrecognized as a common G6PD-deficient variant G6PD Cairo(c.) (404C) . The high prevalence of G6PD deficiency, as well as dietary factors in the region that precipitate anemia, argues for a need to protect the Palestinian children from a treatable and manageable genetic and metabolic disorder. This work reviews and discusses rationales and challenges of G6PD screening program in Gaza Strip. We advocate adopting a national neonatal G6PD screening program in Gaza Strip to identify children at risk and promote wellness and health for Palestine.

Assessment of G6PD screening program in premature infants in a NICU

OBJECTIVE

Targeted screening for glucose-6-phosphate dehydrogenase deficiency (G6PDdef) using fluorescent spot test (FST) is done in our newborn nursery (NN) and now in our NICU. Premature infants have higher G6PD levels than term infants. FST may result in under diagnosis of G6PDdef in preterms. We sought to determine if FST is appropriate for diagnosis of G6PDdef at<35 weeks and assess screening in NICU.

STUDY DESIGN

Retrospective chart review of male, inborn infants<35 weeks in NICU from 2008 to 2011. Difference in G6PDdef incidence<5% between NN and NICU was acceptable for equivalence.

RESULTS

Out of 679 subjects, 442 were screened for G6PDdef and 11.3% had abnormal results. Binomial testing comparing 11.3% (95% confidence interval (CI) 8.5 to 14.6) incidence of G6PDdef in NICU and reported incidence in NN (11%) demonstrated no difference. 12.2% of Black/African American males were not screened.

CONCLUSION

FST is appropriate for screening all at-risk newborns. A number of at-risk premature males were not screened.

Glucose-6-phosphate dehydrogenase activity levels in white newborn infants

OBJECTIVE

To define normal levels of glucose-6-phosphate dehydrogenase (G6PD) activity in a population of North American white newborns.

STUDY DESIGN

We studied 2 white newborn populations, ≥35 weeks of gestation. In the retrospective study, G6PD activity was measured (on clinical indication) in 242 newborns aged ≤7 days. In the prospective study, we measured G6PD activity in umbilical cord blood samples in 347 newborns and daily transcutaneous bilirubin levels in these infants.

RESULTS

The mean G6PD activity level was 12.3 ± 3.1 units per gram hemoglobin (U/gHb) in the retrospective population and 13.3 ± 1.8 U/gHb in the prospective population, and there was no difference between males and females. The distribution of values suggested that infants with activity levels <7 U/gHb should be considered deficient and 8 infants (6 males and 2 females), all in the retrospective population had such levels.

CONCLUSIONS

As in other ethnic populations, the mean G6PD activity in white newborn infants is substantially greater than that of white adults. The lower limits of normal are also similar to those of other newborn ethnic groups and of adults. The diagnosis of G6PD deficiency should be considered in any white infant whose G6PD activity is <7 U/gHb.

Lower reference limits of quantitative cord glucose-6-phosphate dehydrogenase estimated from healthy term neonates according to the Clinical and Laboratory Standards Institute guidelines: a cross sectional retrospective study

BACKGROUND

Previous studies have reported the lower reference limit (LRL) of quantitative cord glucose-6-phosphate dehydrogenase (G6PD), but they have not used approved international statistical methodology. Using common standards is expecting to yield more true findings. Therefore, we aimed to estimate LRL of quantitative G6PD detection in healthy term neonates by using statistical analyses endorsed by the International Federation of Clinical Chemistry (IFCC) and the Clinical and Laboratory Standards Institute (CLSI) for reference interval estimation.

METHODS

This cross sectional retrospective study was performed at King Abdulaziz Hospital, Saudi Arabia, between March 2010 and June 2012. The study monitored consecutive neonates born to mothers from one Arab Muslim tribe that was assumed to have a low prevalence of G6PD-deficiency. Neonates that satisfied the following criteria were included: full-term birth (37 weeks); no admission to the special care nursery; no phototherapy treatment; negative direct antiglobulin test; and fathers of female neonates were from the same mothers' tribe. The G6PD activity (Units/gram Hemoglobin) was measured spectrophotometrically by an automated kit. This study used statistical analyses endorsed by IFCC and CLSI for reference interval estimation. The 2.5th percentiles and the corresponding 95% confidence intervals (CI) were estimated as LRLs, both in presence and absence of outliers.

RESULTS

207 males and 188 females term neonates who had cord blood quantitative G6PD testing met the inclusion criteria. Method of Horn detected 20 G6PD values as outliers (8 males and 12 females). Distributions of quantitative cord G6PD values exhibited a normal distribution in absence of the outliers only. The Harris-Boyd method and proportion criteria revealed that combined gender LRLs were reliable. The combined bootstrap LRL in presence of the outliers was 10.0 (95% CI: 7.5-10.7) and the combined parametric LRL in absence of the outliers was 11.0 (95% CI: 10.5-11.3).

CONCLUSION

These results contribute to the LRL of quantitative cord G6PD detection in full-term neonates. They are transferable to another laboratory when pre-analytical factors and testing methods are comparable and the IFCC-CLSI requirements of transference are satisfied. We are suggesting using estimated LRL in absence of the outliers as mislabeling G6PD-deficient neonates as normal is intolerable whereas mislabeling G6PD-normal neonates as deficient is tolerable.

Glucose-6-phosphate dehydrogenase deficiency and borderline deficiency: association with neonatal hyperbilirubinemia

OBJECTIVE

To characterize the occurrence of glucose-6-phosphate dehydrogenase (G6PD) deficiency and its association with neonatal hyperbilirubinemia.

STUDY DESIGN

This study involved an evaluation of G6PD data for 2656 newborns from a universal newborn screening program.

RESULTS

Mean G6PD activity was 14.2 ± 3.3 U/g Hb. Some 2.71% of the newborns were G6PD-deficient, and 1.77% had borderline G6PD activity, with male and female predominance, respectively. G6PD deficiency was more prevalent in newborns of Sephardic Jew and Muslim Arab backgrounds. The infants with G6PD deficiency had higher bilirubin levels at the time of discharge from the nursery. Infants with low and borderline G6PD activity were more likely to require phototherapy (22.2% and 25.5%, respectively, vs 7.6% of infants with normal G6PD activity; P < .005) and to have more referrals for exacerbation of jaundice (15.3% and 14.9%, respectively, vs 6.1%; P < .005). Mean G6PD activity was higher in preterm infants born at 27-34 weeks gestational age compared with those born later (16.3 ± 1.8 U/g Hb vs 14.8 ± 2.0 U/g Hb). Based on sex distribution and theoretical genetic calculations for the rate of heterozygous females, we propose that the range of borderline G6PD activity should be 2-10 U/g Hb rather than the currently accepted range of 2-7 U/g Hb.

CONCLUSIONS

There is association between G6PD deficiency and significant neonatal hyperbilirubinemia. Increased risk is also associated with borderline G6PD activity. The suggested new range for borderline G6PD activity should enhance the identification of females at risk. G6PD activity is higher in preterm infants.

Oxidative Stress and Antioxidant Enzyme Activities in Newborns with Oesophageal Atresia and Their Mothers

OBJECTIVE: To measure the oxidant/antioxidant status of newborn babies with oesophageal atresia and their mothers, compared with healthy control subjects. METHODS: This case—control study included 40 participants: 10 newborns with oesophageal atresia and their mothers, and 10 healthy newborns and their mothers. Whole blood malondialdehyde (MDA) levels and the activities of antioxidant enzymes (catalase, carbonic anhydrase [CA], glucose-6-phosphate dehydrogenase [G-6-PD], and superoxide dismutase [SOD]) were measured. RESULTS: MDA levels and CA activity were significantly higher, and catalase, SOD and G-6-PD activities were significantly lower, in newborns with oesophageal atresia and their mothers than in healthy newborns and their mothers. Although CA activity was similar between the newborns and mothers in the patient group, it was significantly lower in newborns than in mothers in the healthy group. CONCLUSIONS: Increased lipid peroxidation might play an important role in the pathogenesis of oesophageal atresia. Impairment of the free radical/antioxidant balance may lead to increased free radical and decreased antioxidant levels in oesophageal atresia.

Comparative analysis of glucose-6-phosphate dehydrogenase levels in pre-term and term babies delivered at University of Ilorin Teaching Hospital

Glucose-6-phosphate (G6P) is an enzyme in the hexose monophosphate shunt required for the production of reducing equivalents needed to mop up free radicals. thereby keeping hemoglobin in its free state. Deficiency of the enzyme can cause severe neonatal jaundice. The aim of this study was to compare G6PD levels in pre-term and term babies, and evaluate the extent to which G6PD deficiency determines the severity of jaundice in various gestational age groups. Samples of cord blood collected from consecutively delivered babies in the University of Ilorin Teaching Hospital, Nigeria, were assayed for G6PD levels, and the babies were observed for jaundice during the first week of life. Those who developed jaundice had serial serum bilirubin measured. Nine hundred and thirty-three babies had G6PD assayed, with 348 being G6PD deficient, giving a hospital based prevalence of 37.3%. Of the 644 who were followed up, 143 (22.2%) were pre-term and 501(77.8%) were term babies. Babies with gestational age (GA) 27-29 weeks had the highest G6PD levels. However, there was no significant variation among the different gestational age groups (F=0.64, P=0.64). Jaundice occurred more in pre-term compared to term babies with a relative risk of 2.41 (χ(2)=60.95, P=0.00001). Occurrence of jaundice in pre-term babies was irrespective of G6PD status (χ(2)=0.2, P=0.66, RR=1.09, CI=0.83<RR<1.43). There is an inverse relationship between gestational age and the occurrence of jaundice (R(2)=-0.874). Pre-term babies are more likely to have higher G6PD levels, but occurrence of jaundice in pre-term babies is irrespective of G6PD status. More severe jaundice (especially for gestational age) occurring in pre-term babies requires critical care.

Potential risks of hemolysis after short-term administration of analgesics in children with glucose-6-phosphate dehydrogenase deficiency

OBJECTIVE

To evaluate the risk of hemolysis in children with glucose-6-phosphate dehydrogenase (G6PD) deficiency after short-term administration of analgesics, such as paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib.

STUDY DESIGN

This was a prospective study of children with G6PD deficiency who were treated with analgesics for 3 days after undergoing surgery. Hemoglobin (Hb) concentration, reticulocyte count, unconjugated bilirubin level, lactate dehydrogenase level, and the presence of Heinz bodies on blood smear microscopy were assessed at baseline and after analgesic treatment. Telephone interviews and clinical reviews were provided during a 7-day study period. The primary outcome was evidence of hemolysis. Statistical analyses were done using the paired Student t test or Wilcoxon signed-rank test as appropriate.

RESULTS

Ten male infants (mean age, 4.3 ± 1.3 years) completed the study. The mean decrease in (Hb) concentration was -0.2 g/dL (P, not significant). The mean reticulocyte count increased by 0.1% (95% CI, 0.08%-0.2%; P = .001). However, the change in reticulocyte count was not correlated with the changes in Hb concentration or other laboratory results and was not accompanied by the clinical signs and symptoms of hemolysis.

CONCLUSION

Short-term administration of paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib in therapeutic dosages did not increase the risk of hemolysis in children with G6PD deficiency.

Glucose-6-phosphate dehydrogenase activity in term and near-term, male African American neonates

BACKGROUND

We determined values for glucose-6-phosphate dehydrogenase (G-6-PD) activity in African American neonates.

METHODS

G-6-PD activity was measured on umbilical cord blood from term and near-term healthy, male neonates. Neonates were stratified according to the number of neonates for each numerical unit of G-6-PD activity. Corrected end tidal carbon monoxide (ETCOc), a non-invasive index of hemolysis, was performed on each neonate. At least one predischarge transcutaneous bilirubin determination was performed.

RESULTS

Five hundred neonates were studied. Two subpopulations were apparent, with no overlap between the subgroups. Mean value for the 64 (12.8%) infants with the lower values (G-6-PD deficient) was 2.7+/-1.1 U/g Hb, range 0.4-6.6 U/g Hb, while that for the 436 neonates with the higher values (G-6-PD normal) was 21.8+/-2.9 U/g Hb, range 14.5-33.8 U/g Hb. No significant differences in activity were noted between those neonates <37 weeks gestational age and those >37 weeks. Enzyme activity in the lower range in both groups was not related to the development of hyperbilirubinemia. G-6-PD enzyme activity did not correlate with ETCOc values either for the entire cohort or for the individual subsets.

CONCLUSIONS

G-6-PD-deficient neonates formed a separate subgroup from those with normal enzyme activity. The data supplied should facilitate interpretation of G-6-PD test results.