Glucose-6-Phosphate Dehydrogenase Deficiency and the Benefits of Early Screening

Prevalence of Glucose-6-Phosphate Dehydrogenase Deficiency in Newborns in Northeast Mexico

OBJECTIVE

 Glucose-6-phosphate dehydrogenase deficiency (G6PDd) is the most common enzymatic disease worldwide and the prevalence is not well established because of the lack of screening. This study aimed to estimate the prevalence of G6PDd in a Hispanic population from Northeast Mexico.

STUDY DESIGN

 In this retrospective study, a database was used to analyze the G6PDd in neonates included in the expanded newborn metabolic screening of inherited metabolic disorders during a period of 4 years through the GSP Neonatal G6 kit (PerkinElmer).

RESULTS

 Among 96,152 (48,462 male) neonates screened for G6PD enzyme activity, a total of 566 (0.58%) cases were deficient for G6PD. Of those 566 patients, 469 (82.8%) attended the second test and the other 97 (17.2%) patients were lost. Of those 469 who did attend, 384 (81.9%) neonates were deficient in the second test and 85 (18.1%) were normal. With the data collected, 384 neonates were confirmed with G6PDd, 348 (88.6%) were male and 36 (11.4%) patients were female. The calculated prevalence for this population was 0.72 cases per 100 male newborns.

CONCLUSION

 The prevalence of G6PDd in the Northeastern Mexican population is high. Since migration is increasing in the United States, pediatricians should be aware of the need to search for G6PDd in newborns and the wide clinical manifestations they can present.

KEY POINTS

· The calculated prevalence of glucose-6-phosphate dehydrogenase deficiency in Northeast Mexico is 3.99 cases per 1,000 newborns.. · Glucose-6-phosphate dehydrogenase deficiency screenings should be included in all newborn metabolic screenings.. · Glucose-6-phosphate dehydrogenase deficiency is a common erythroenzymopathy that must be addressed as a public health concern. To anticipate clinical complications, target population monitoring is required..

Newborn screening for G6PD deficiency in HeFei, FuYang and AnQing, China: Prevalence, cut-off value, variant spectrum

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive Mendelian genetic disorder characterized by neonatal jaundice and hemolytic anemia, affecting more than 400 million people worldwide. The purpose of this research was to investigate prevalence rates of G6PD deficiency and to evaluate and establish specific cut-off values in early prediction of G6PD deficiency by regions (HeFei, FuYang, AnQing) on different seasons, as well as to investigate the frequencies of G6PD gene mutations among three regions mentioned above.

Methods

A total of 31,482 neonates (21,402, 7680, and 2340 for HeFei, FuYang, and AnQing cities, respectively) were recruited. Positive subjects were recalled to attend genetic tests for diagnosis. G6PD activity on the Genetic screening processor (GSP analyzer, 2021-0010) was measured following the manufactureržs protocol. The cut-off value was first set to 35 U/dL. The receiver operating characteristics (ROC) curve was employed to assess and compare the efficiency in predicting G6PD deficiency among HeFei, FuYang, and AnQing cities in different seasons.

Epidemiology of Glucose-6-Phosphate Dehydrogenase Deficiency in Arab Countries: Insights from a Systematic Review

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common metabolic disorder affecting more than 400 million individuals worldwide. Being an X-linked disorder, the disease is more common among males than females. Various Arab countries estimated the prevalence of G6PD deficiency; however, findings from different countries have not been synthesized collectively. Hence, a systematic review was undertaken to synthesize the findings on the epidemiology of G6PD deficiency in all Arab countries. We performed an electronic systematic literature search based on the eligibility criteria using databases, including MEDLINE, Embase, and CINHAL. The studies included in the review were primary and original research studies assessing the prevalence or incidence, risk factors, or determinants of G6PD deficiency, and published in the English language in a peer-reviewed scientific journal between 2000 and 2022. The systematic review was carried out with the help of an updated PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. After the screening, 23 full texts were finalized for data extraction. The prevalence of G6PD deficiency ranged from 2 to 31% with a greater burden among high-risk populations like neonates with sickle cell anemia. The determinants included males, family history, consanguineous marriages, and geographic regions, which were all risk factors, except for body weight, which was a protective factor. The prevalence of G6PD deficiency varies across Arab countries, with a higher prevalence in males than females. Different regions of Arab countries need to revisit their screening and diagnostic guidelines to detect G6PD deficiency promptly and prevent unnecessary morbidity and mortality among their communities.

Functional interpretation, cataloging, and analysis of 1,341 glucose-6-phosphate dehydrogenase variants

Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects over 500 million individuals who can experience anemia in response to oxidative stressors such as certain foods and drugs. Recently, the World Health Organization (WHO) called for revisiting G6PD variant classification as a priority to implement genetic medicine in low- and middle-income countries. Toward this goal, we sought to collect reports of G6PD variants and provide interpretations. We identified 1,341 G6PD variants in population and clinical databases. Using the ACMG standards and guidelines for the interpretation of sequence variants, we provided interpretations for 268 variants, including 186 variants that were not reported or of uncertain significance in ClinVar, bringing the total number of variants with non-conflicting interpretations to 400. For 414 variants with functional or clinical data, we analyzed associations between activity, stability, and current classification systems, including the new 2022 WHO classification. We corroborated known challenges with classification systems, including phenotypic variation, emphasizing the importance of comparing variant effects across individuals and studies. Biobank data made available by All of Us illustrate the benefit of large-scale sequencing and phenotyping by adding additional support connecting variants to G6PD-deficient anemia. By leveraging available data and interpretation guidelines, we created a repository for information on G6PD variants and nearly doubled the number of variants with clinical interpretations. These tools enable better interpretation of G6PD variants for the implementation of genetic medicine.

Technical evaluation and usability of a quantitative G6PD POC test in cord blood: a mixed-methods study in a low-resource setting

OBJECTIVES

New point-of-care (POC) quantitative G6PD testing devices developed to provide safe radical cure for Plasmodium vivax malaria may be used to diagnose G6PD deficiency in newborns at risk of severe neonatal hyperbilirubinaemia, improving clinical care, and preventing related morbidity and mortality.

METHODS

We conducted a mixed-methods study analysing technical performance and usability of the 'STANDARD G6PD' Biosensor when used by trained midwives on cord blood samples at two rural clinics on the Thailand-Myanmar border.

RESULTS

In 307 cord blood samples, the Biosensor had a sensitivity of 1.000 (95% CI: 0.859 to 1.000) and a specificity of 0.993 (95% CI: 0.971 to 0.999) as compared with gold-standard spectrophotometry to diagnose G6PD-deficient newborns using a receiver operating characteristic (ROC) analysis-derived threshold of ≤4.8 IU/gHb. The Biosensor had a sensitivity of 0.727 (95% CI: 0.498 to 0.893) and specificity of 0.933 (95% CI: 0.876 to 0.969) for 30%-70% activity range in girls using ROC analysis-derived range of 4.9-9.9 IU/gHb. These thresholds allowed identification of all G6PD-deficient neonates and 80% of female neonates with intermediate phenotypes.Need of phototherapy treatment for neonatal hyperbilirubinaemia was higher in neonates with deficient and intermediate phenotypes as diagnosed by either reference spectrophotometry or Biosensor.Focus group discussions found high levels of learnability, willingness, satisfaction and suitability for the Biosensor in this setting. The staff valued the capacity of the Biosensor to identify newborns with G6PD deficiency early ('We can know that early, we can counsel the parents about the chances of their children getting jaundice') and at the POC, including in more rural settings ('Because we can know the right result of the G6PD deficiency in a short time, especially for the clinic which does not have a lab').

CONCLUSIONS

The Biosensor is a suitable tool in this resource-constrained setting to identify newborns with abnormal G6PD phenotypes at increased risk of neonatal hyperbilirubinaemia.

An Evaluation of a New Quantitative Point-of Care Diagnostic to Measure Glucose-6-phosphate Dehydrogenase Activity

Malaria continues to be one of the most crucial infectious burdens in endemic areas worldwide, as well as for travelers visiting malaria transmission regions. It has been reported that 8-aminoquinolines are effective against the Plasmodium species, particularly primaquine, for anti-hypnozoite therapy in P. vivax malaria. However, primaquine causes acute hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Therefore, G6PD deficiency testing should precede hypnozoite elimination with 8-aminoquinoline. Several point-of-care devices have been developed to detect G6PD deficiency. The aim of the present study was to evaluate the performance of a novel, quantitative G6PD diagnostics based on a metagenomic blue fluorescent protein (mBFP). We comparatively evaluated the sensitivity and specificity of the G6PD diagnostic modality with standard methods using 120 human whole blood samples. The G6PD deficiency was spectrophotometrically confirmed. The performance of the G6PD quantitative test kit was compared with that of a licensed control medical device, the G6PD strip. The G6PD quantitative test kit had a sensitivity of 95% (95% confidence interval (CI): 89.3–100%) and a specificity of 100% (95% CI: 94.3–100%). This study shows that the novel diagnostic G6PD quantitative test kit could be a cost-effective and time-efficient, and universally mandated screening tool for G6PD deficiency.

Thirty-five males with severe (Class 1) G6PD deficiency (c.637G>T) in a North American family of European ancestry

In North America, jaundiced neonates are not usually tested for G6PD deficiency if the family is of European ancestry. However, we describe such a family where ≥35 males have had severe (Class I) G6PD deficiency. Many of the jaundiced neonates did not have this diagnosis considered, at least three of whom developed bilirubin neurotoxicity. Over seven generations 35 affected males were identified. Three developed signs of kernicterus spectrum disorder; three had exchange transfusions for hyperbilirubinemia; and nine received one or more blood transfusions during childhood.

Severe Presentation of Congenital Hemolytic Anemias in the Neonatal Age: Diagnostic and Therapeutic Issues

Congenital hemolytic anemias (CHAs) are a group of diseases characterized by premature destruction of erythrocytes as a consequence of intrinsic red blood cells abnormalities. Suggestive features of CHAs are anemia and hemolysis, with high reticulocyte count, unconjugated hyperbilirubinemia, increased lactate dehydrogenase (LDH), and reduced haptoglobin. The peripheral blood smear can help the differential diagnosis. In this review, we discuss the clinical management of severe CHAs presenting early on in the neonatal period. Appropriate knowledge and a high index of suspicion are crucial for a timely differential diagnosis and management. Here, we provide an overview of the most common conditions, such as glucose-6-phosphate dehydrogenase deficiency, pyruvate kinase deficiency, and hereditary spherocytosis. Although rare, congenital dyserythropoietic anemias are included as they may be suspected in early life, while hemoglobinopathies will not be discussed, as they usually manifest at a later age, when fetal hemoglobin (HbF) is replaced by the adult form (HbA).

Genetic spectrum and clinical early natural history of glucose-6-phosphate dehydrogenase deficiency in Mexican children detected through newborn screening

BACKGROUND

Glucose-6-phosphate dehydrogenase deficiency (G6PDd) newborn screening is still a matter of debate due to its highly heterogeneous birth prevalence and clinical expression, as well as, the lack of enough knowledge on its natural history. Herein, we describe the early natural clinical course and the underlying GDPD genotypes in infants with G6PDd detected by newborn screening and later studied in a single follow-up center. G6PDd newborns were categorized into three groups: group 1: hospitalized with or without neonatal jaundice (NNJ); group 2: non-hospitalized with NNJ; and group 3: asymptomatic. Frequencies of homozygous UGT1A1*28 (rs34983651) genotypes among G6PDd patients with or without NNJ were also explored.

RESULTS

A total of 81 newborns (80 males, one female) were included. Most individuals (46.9%) had NNJ without other symptoms, followed by asymptomatic (42.0%) and hospitalized (11.1%) patients, although the hospitalization of only 3 of these patients was related to G6PDd, including NNJ or acute hemolytic anemia (AHA). Nine different G6PDd genotypes were found; the G6PD A-202A/376G genotype was the most frequent (60.5%), followed by the G6PD A-376G/968C (22.2%) and the Union-Maewo (rs398123546, 7.4%) genotypes. These genotypes produce a wide range of clinical and biochemical phenotypes with significant overlapping residual enzymatic activity values among class I, II or III variants. Some G6PD A-202A/376G individuals had enzymatic values that were close to the cutoff value (5.3 U/g Hb, 4.6 and 4.8 U/g Hb in the groups with and without NNJ, respectively), while others showed extremely low enzymatic values (1.1 U/g Hb and 1.4 U/g Hb in the groups with and without NNJ, respectively). Homozygosity for UGT1A1*28 among G6PDd patients with (11.9%, N = 5/42) or without (10.3%, N = 4/39) NNJ did not shown significant statistical difference (p = 0.611).

CONCLUSION

Wide variability in residual enzymatic activity was noted in G6PDd individuals with the same G6PD genotype. This feature, along with a documented heterogeneous mutational spectrum, makes it difficult to categorize G6PD variants according to current WHO classification and precludes the prediction of complications such as AHA, which can occur even with > 10% of residual enzymatic activity and/or be associated with the common and mild G6PD A-376G/968C and G6PD A-202A/376G haplotypes.