Evaluation of strategies for identification of infants with pathogenic glucose-6-phosphate dehydrogenase variants in China

Rapid and reliable detection of G6PD mutations using recombinase polymerase amplification coupled with lateral flow strip

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy, affecting approximately 500 million people worldwide. It results from inherited mutations in the G6PD gene, causing increased susceptibility to drug-induced hemolytic anemia and severe neonatal jaundice. While phenotypic tests are commonly used, genetic testing is increasingly recognized for its value in the accurate diagnosis of G6PD deficiency, especially in heterozygous females and newborns. This study aimed to develop and evaluate a rapid, field-deployable genetic test for the detection of four common G6PD variants in Thailand: G6PD Gaohe (c.95A > G), G6PD Mahidol (c.487G > A), G6PD Viangchan (c.871G > A), and G6PD Canton (c.1376G > T). The assays utilize recombinase polymerase amplification with allele-specific primers incorporating locked nucleic acids to enhance specificity, followed by lateral flow strip detection for visual readout. The assays deliver results within 45 min at 37 ˚C. Singleplex detection demonstrated 100 % diagnostic sensitivity (Confidence interval (CI): 95.01-100.0 %) and specificity (CI: 95.49-100.0 %). Duplex assays (Gaohe + Canton and Mahidol + Viangchan) also demonstrated 100 % diagnostic sensitivity (CI: 94.87-100.0 %) and specificity (CI: 91.19-100.0 %). Limits of detection (LOD) for singleplex assays were 0.25, 1.00, 0.50, and 0.50 ng/µL, for Gaohe, Mahidol, Viangchan, and Canton, respectively. Duplex assays showed LODs of 0.10 ng/μL for Mahidol + Viangchan and 10.00  ng/μL for Gaohe + Canton. Band intensity differences ranged from 5.25 to 19.61 pixels between mutant, wild-type, and nontarget alleles, enabling clear allele discrimination. This innovative diagnostic tool offers a rapid, reliable, and accessible solution for point-of-care genetic testing, with the potential to improve clinical management and healthcare outcomes in regions with a high burden of G6PD deficiency.

Screening results and mutation frequency analysis of G6PD deficiency in 1,291,274 newborns in Huizhou, China: a twenty-year experience

OBJECTIVES

This study aimed to investigate the incidence rate and spectrum of gene mutations of Glucose-6-phosphate dehydrogenase (G6PD) deficiency in the Huizhou city of southern China to provide a scientific basis for disease prevention and control in the area.

METHODS

From March 2003 to December 2022, newborn screening for G6PD enzyme activity was carried out in Huizhou city using the fluorescence quantitative method. Infants who tested positive during the initial screening were diagnosed using the nitroblue tetrazolium ratio method, while a subset of infants received further gene mutation analysis using the multicolor probe melting curve analysis method.

RESULTS

A total of 1,291,274 newborns were screened and the screening rate has increased from 20.39% to almost 100%. In the 20-year period, 57,217 (4.43%) infants testing positive during the initial screening. Out of these infants, 49,779 (87%) were recalled for confirmatory testing. G6PD deficiency was confirmed in 39,261 of the recalled infants, indicating a positive predictive value of 78.87%. The estimated incidence rate of G6PD deficiency in the region was 3.49%, which was significantly higher than the average incidence rate of 2.1% in southern China. On the other hand, seven pathogenic G6PD variants were identified in the analysis of the 99 diagnosed infants with the most common being c.1388 G > A (48.5%), followed by c.95 A > G (19.2%), c.1376 G > T (15.2%), c.871 G > A (9.1%), c.1360 C > T (3.0%), c.392 G > T (3.0%), and c.487 G > A (1.0%).

CONCLUSION

The incidence of G6PD deficiency in newborns in the Huizhou city was higher than the southern China average level, while the types and frequencies of gene mutations were found to vary slightly from other regions. Our findings suggested that free government screening and nearby diagnosis strategies could reduce the incidence of G6PD deficiency in the area.

Severe G6PD deficiency leads to recurrent infections and defects in ROS production: Case report and literature review

Purpose: Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency can lead to reduced nicotinamide adenine dinucleotide phosphate oxidase activity in phagocytes, resulting in immunodeficiency, with a limited number of reported cases. Here, we aimed to report a child with severe G6PD deficiency in China and investigate the mechanism of his recurrent infections.

Methods: The clinical manifestations and immunological phenotypes of this patient were retrospectively collected. Gene mutation was detected by whole-exome sequencing and confirmed by Sanger sequencing. Dihydrorhodamine (DHR) analysis was performed to measure the respiratory burst of neutrophils. Messenger ribonucleic acid and protein levels were detected in the patient under lipopolysaccharide stimulation by real-time quantitative reverse transcription polymerase chain reaction and Western blot. A review of the literature was performed.

Results: A male child with G6PD deficiency presented with recurrent respiratory infections, Epstein‒Barr virus infection and tonsillitis from 8 months of age. Gene testing revealed that the proband had one hemizygous mutation in the G6PD gene (c.496 C>T, p. R166C), inherited from his mother. This mutation might affect hydrophobic binding, and the G6PD enzyme activity of the patient was 0. The stimulation indexes of the neutrophils in the patient and mother were 22 and 37, respectively. Compared with healthy controls, decreased reactive oxygen species (ROS) production was observed in the patient. Activation of nuclear factor kappa-B (NF-κB) signaling was found to be influenced, and the synthesis of tumor necrosis factor alpha (TNF-α) was downregulated in the patient-derived cells. In neutrophils of his mother, 74.71% of the X chromosome carrying the mutated gene was inactivated. By performing a systematic literature review, an additional 15 patients with severe G6PD deficiency and recurrent infections were identified. Four other G6PD gene mutations have been reported, including c.1157T>A, c.180_182del, c.514C>T, and c.953_976del.

Conclusion: Severe G6PD deficiency, not only class I but also class II, can contribute to a chronic granulomatous disease-like phenotype. Decreased reactive oxygen species synthesis led to decreased activation of the NF-κB pathway in G6PD-deficient patients. Children with severe G6PD deficiency should be aware of immunodeficiency disease, and the DHR assay is recommended to evaluate neutrophil function for early identification.