Characterization of mutations and polymorphisms in the G6PD among Filipino newborns with glucose-6-phosphate dehydrogenase deficiency

Background. Glucose-6-phosphate (G6PD) deficiency is the most prevalent enzyme deficiency to date. The global prevalence of G6PD deficiency is estimated at around 330 million people affected with the disease worldwide. This 4.9 percent prevalence, correlates highly with geographic areas endemic to malaria. It is the most common among the disorders in the Newborn Screening (NBS) panel in the Philippines, with one confirmed case for every 52 newborns (1:52). This paper determines the molecular background of G6PD deficiency among Filipino newborns detected by newborn screening. Methods. A total of 200 cases confirmed to have G6PD deficiency, 180 males and 20 females, were identified through the Philippine Newborn Screening Program from 2001-2003. Genomic DNA was extracted from dried blood spots followed by multiplex polymerase chain reaction using multiple tandem forward primers and a common reverse primer (MPTP) to detect previously reported common mutations and polymorphisms in exons 5, 6, 9, 11 and 12 of the G6PD gene. Results. Of the 200 samples analyzed, mutations and polymorphisms in the G6PD gene were identified in 148 cases (74%). The most common mutation was a G to A transition on nucleotide 871 (Viangchan) of exon 9 in combination with a silent mutation on exon 11, accounting for 32.9% of the cases. This was followed by a C to T transition on nucleotide 1360 (Union) in 21.1 % of the cases. Other mutations were Vanua Lava in 10%, Chatham in 9.4% and Canton in 3.5% of the newborns. The silent polymorphism on nucleotide 1311 was present in 12.9% of cases. There were combinations of these mutations and polymorphisms present in a minority of cases. Conclusion. Results of this study showed the molecular heterogeneity underlying G6PD deficiency among Filipino newborns.

Glucose-6-phosphate dehydrogenase deficiency: molecular heterogeneity in southeast Asian countries.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is common in malaria endemic regions and is estimated to affect more than 400 million people worldwide. Deficient subjects are mostly asymptomatic but clinical manifestations range from neonatal jaundice due to acute hemolytic anemia to chronic non-spherocytic hemolytic anemia. To date, biochemical parameters allowed more than 400 different G6PD variants to be distinguished thereby suggesting a vast genetic heterogeneity. So far, only a small portion of this heterogeneity has been confirmed at the DNA level with the identification of about 90 different point mutations in the G6PD coding sequence. To determine the molecular background of G6PD deficiency in Southeast Asian countries, we conducted molecular analyses of G6PD patients from the Philippines, Malaysia, Singapore, Vietnam and Indonesia. The most prevalent mutation identified differs from country to country, thus suggesting independent mutational events of the G6PD gene.

G6PD Viangchan and G6PD Mediterranean are the main variants in G6PD deficiency in the Malay population of Malaysia.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs of acute hemolytic anemia. Mutations of the G6PD gene in the Malay population with G6PD deficiency in Kelantan, a state in North East Malaysia were studied. Ninety-three individuals with G6PD deficiency were subjected to mutation analysis of the G6PD gene using polymerase chain reaction based techniques of multiplex PCR. Of the ninety-three DNA samples studied, molecular defects were identified in 80 cases (86%). Variants were heterogeneous - 28.7% were found to have a G to A nucleotide change at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan. The other major mutations were G6PD Mediterranean, G6PD Vanua Lava, G6PD Coimbra, G6PD Kaiping, G6PD Orissa, G6PD Mahidol, G6PD Canton and G6PD Chatham. These results showed that there are heterogeneous mutations of the G6PD gene associated with G6PD deficiency and that G6PD Viangchan and G6PD Mediterranean account for the main variants in G6PD deficiency among the Malay population in Malaysia.

Nasopharyngeal carcinoma in Indonesia has a low prevalence of the 30-base pair deletion of Epstein-Barr virus latent membrane protein 1.

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), one of the highest incidence of tumors in Indonesia. EBV infection is ubiquitous around the world, but NPC occurs with a remarkable geographic distribution. This phenomenon suggests that there are subtypes of EBV, some of which may have greater tumorigenic potential. The latent membrane protein 1 (LMP 1) gene encoded by EBV is tumorigenic due to its ability to transform rodent fibroblast. It was originally shown that the LMP 1 gene from NPC of Chinese patients harbors a deletion of 30-bp in the carboxyl terminal of the gene. However, the deletion is also present in healthy control and in other EBV-positive tumors. We examined the polymorphism of LMP 1 in 56 tumor biopsies of Indonesian patients with NPC and identified low prevalence of the 30-bp deletion of LMP 1. Sequence analysis showed unique mutations of LMP 1 which suggests that strain-specific variations of EBV are found in Indonesia. The low frequency of 30-bp deletion in the country with high prevalence of NPC indicates that the deletion may represent a geographic polymorphism rather than a predisposing factor in the development of NPC.

Identification of point mutations in Glucose-6-Phosphate Dehydrogenase gene in Timor Island people : A preliminary report.

Glucose 6 phosphate dehydrogenase (G6PD) deficiency is common in malaria endemic region, however no molecular study has been performed on G6PD deficiency in Timor Island, Indonesia a malarial hyperendemic area which Proto Malay is the majority of the people in that island. To observe the frequency and molecular type of mutations in G6PD deficient Proto Malay people, 118 native people were screened using formazan ring test. Mutation in the G6PD gene were determined by MPTP (Multiple PCR using Multiple Tandem Forward Primers and a common Reserve Pimer) method and confirmed by automatic sequencer. This study shows that three males have lower G6PD activity. Using MPTP method, a point mutation could be indicated in the two cases. Sequencing of the amplified products in 2 G6PD patients disclosed mutations of T383C in exon 5 and C 592 T in exon 6 in respective case. Our result documents point mutations in exon 5 and exon 6 in the G6PD gene of two Proto Malay people in Timor. These mutations are common in Asia region.