Molecular genotyping of G6PD mutations for neonates in Ningbo area

Molecular epidemiological investigation of G6PD deficiency in Yangjiang region, western Guangdong province

Objectives: The prevalence of G6PD deficiency has not been reported in Yangjiang, a western city in Guangdong province. This study aims to investigate the molecular characteristics of G6PD deficiency in this region. Methods: Blood samples were collected from adults at a local hospital to screen for G6PD deficiency. The deficient samples were subjected to further analysis using PCR and reverse dot blot to determine the specific G6PD variants. Results: Among the 3314 male subjects, 250 cases of G6PD deficiency were found using the G6PD enzyme quantitative assay, resulting in a prevalence of 7.54% (250/3314) in the Yangjiang region. The prevalence of G6PD deficiency in females was 3.42% (176/5145). Out of the 268 cases of G6PD deficiency tested for G6PD mutations, reverse dot blot identified 20 different G6PD variants. The most common G6PD variant was c.1388G>A (81/268), followed by c.1376G>T (48/268), c.95A>G (32/268), c.1024C>T (9/268), c.392G>T (7/268), and c.871G>A/c.1311C>T (6/268). It was observed that c.871G>A was always linked to the polymorphism of c.1311C>T in this population. Conclusion: This investigation into G6PD deficiency in this area is expected to significantly improve our understanding of the prevalence and molecular characterization of this condition.

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.

An Approach to Re-evaluate the Reference Cutoff of the Parameters of Newborn Screening: An Observational Study

Background Unless a cutoff level of the parameters of newborn screening (NBS) is defined, a screening test's results would end in high recall rates and apprehensive parents. The study aimed to establish a cutoff level of the healthy term newborns. Materials and methods The study was a retrospective observational data analysis on a cohort of 1158 term newborns who underwent NBS in our institute. The percentile distribution of the NBS parameters was computed and the 99th percentile value was considered the new cutoff. For lower values, such as neonatal glucose 6-phosphate dehydrogenase (nG6PD) and neonatal biotinidase (nBIOT), low percentile values were regarded as new cutoff value. Results Neonatal thyroid stimulating hormone (nTSH), nG6PD, neonatal immunoreactive trypsinogen (nIRT), and nBIOT showed a wide variation in the distribution. Most newborns had neonatal galactose (nGAL), nIRT, and nBIOT values above the median. The 99th percentile value of nTSH was 14.5 mIU/L, and that of neonatal 17-hydroxyprogesterone (n17-OHP) was 43.7 nmol/L. The 1.0th percentile value for nG6PD was decreased to 2.18 IU/gHb. The new cutoff values for nBIOT, nIRT, neonatal phenylketonuria (nPKU) and nGAL were 48.59 U, 95.3 µg/L, 2.3 mg/dL and 15.9 mg/dL. The mean and median nTSH values did not significantly differ (p=0.99) in the first five days of birth. On the contrary, the study population depicted considerably raised levels of n17-OHP on day 3, followed by a sharp decrease (p=0.029). Similarly, nIRT displayed significant differences in the first five days (p=0.017). Conclusion Using the 99th percentile values of the NBS parameters as the new cutoff levels might be beneficial in terms of the recall rates and cost burden.

Molecular genotyping of G6PD mutations for neonates in Ningbo area

The aim of this study is to determine the cut-off value of glucose-6-phosphate dehydrogenase (G6PD) activity and the mutation spectrum of G6PD gene in neonates with G6PD deficiency at Ningbo. Around 82233 neonatal blood samples were measured to determine G6PD activity. The positive samples were further detected with gene analysis. A total of 445 neonates were confirmed as G6PD deficiency, and the incidence in Ningbo was 1/185. 17 types of G6PD gene mutations were found, including 11 single-site mutations and 6 double-site mutations. Considering the significant differences in G6PD activity, the cut-off value was detected to be 2.35 and 3.65 U/gHb for males and females, respectively. Significant differences in G6PD activities were noted and found to be varied from 4.61 to 6.02 U/gHb in different seasons (p < 0.0001). G6PD deficiency screening is a significant detection test for neonatal G6PD deficiency prevention. Our study highlights that the screening should be done using different cut-off values according to the sexes in different seasons.