Detection of haemoglobin S using multiplex ligation-dependent probe amplification and flow-through hybridization techniques: experience in a tertiary hospital

Haemoglobin S (HbS, α2β26GluVal) is a variant haemoglobin resulted from GAGGTG mutation on codon 6 of HBB gene. HbS haemoglobinopathy is uncommon in Malaysia and mainly seen in immigrants. However, Malaysian Indians and Malays are rarely affected. This study reviewed the laboratory findings of patients with HbS and the utilization of multiplex ligation-dependent probe amplification (MLPA) and flow-through hybridization (FTH) in the detection of HbS mutation. HbS was identified and quantified by high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and cellulose acetate gel electrophoresis. Molecular analysis was performed using MLPA, FTH and Sanger Sequencing. Two Africans, three Malays and two Indian individuals aged between 2-31 years were identified from our laboratory. Five patients were homozygous HbS, one was compound heterozygous HbS/β-thalassemia and one was a carrier of HbS. The patients with homozygous HbS had their haemoglobin (Hb) ranging from 7.4-10.2 g/dL with HbS and HbF levels of 58.3-94.7% and 1.5-35.5%, respectively. The Hb of compound heterozygous HbS/β-thalassaemia patients was 5.8 g/dL and was normal in heterozygous HbS. HbS, HbF and HbA2 levels for the HbS/β-thalassaemia and the carrier were 67%, 27.2% and 4.2%, and 38.6%, 0.1% and 2.8%, respectively. Both MLPA and FTH successfully detected HbS mutation in all cases but only FTH could identify the zygosity of the HbS mutation together with underlying concomitant β-thalassaemia in a single test

Impact of the Method of G6PD Deficiency Assessment on Genetic Association Studies of Malaria Susceptibility

BACKGROUND:Clinical association studies have yielded varied results regarding the impact of glucose-6-phosphate dehydrogenase (G6PD) deficiency upon susceptibility to malaria. Analyses have been complicated by varied methods used to diagnose G6PD deficiency. METHODOLOGY/PRINCIPAL FINDINGS:We compared the association between uncomplicated malaria incidence and G6PD deficiency in a cohort of 601 Ugandan children using two different diagnostic methods, enzyme activity and G6PD genotype (G202A, the predominant East African allele). Although roughly the same percentage of males were identified as deficient using enzyme activity (12%) and genotype (14%), nearly 30% of males who were enzymatically deficient were wild-type at G202A. The number of deficient females was three-fold higher with assessment by genotype (21%) compared to enzyme activity (7%). Heterozygous females accounted for the majority (46/54) of children with a mutant genotype but normal enzyme activity. G6PD deficiency, as determined by G6PD enzyme activity, conferred a 52% (relative risk [RR] 0.48, 95% CI 0.31-0.75) reduced risk of uncomplicated malaria in females. In contrast, when G6PD deficiency was defined based on genotype, the protective association for females was no longer seen (RR = 0.99, 95% CI 0.70-1.39). Notably, restricting the analysis to those females who were both genotypically and enzymatically deficient, the association of deficiency and protection from uncomplicated malaria was again demonstrated in females, but not in males (RR = 0.57, 95% CI 0.37-0.88 for females). CONCLUSIONS/SIGNIFICANCE:This study underscores the impact that the method of identifying G6PD deficient individuals has upon association studies of G6PD deficiency and uncomplicated malaria. We found that G6PD-deficient females were significantly protected against uncomplicated malaria, but this protection was only seen when G6PD deficiency is described using enzyme activity. These observations may help to explain the discrepancy in some published association studies involving G6PD deficiency and uncomplicated malaria

Prevalence and molecular characterization of Glucose-6-Phosphate dehydrogenase deficient variants among the Kurdish population of Northern Iraq

<p>Abstract</p> <p>Background</p> <p>Glucose-6-Phosphate dehydrogenase (G6PD) is a key enzyme of the pentose monophosphate pathway, and its deficiency is the most common inherited enzymopathy worldwide. G6PD deficiency is common among Iraqis, including those of the Kurdish ethnic group, however no study of significance has ever addressed the molecular basis of this disorder in this population. The aim of this study is to determine the prevalence of this enzymopathy and its molecular basis among Iraqi Kurds.</p> <p>Methods</p> <p>A total of 580 healthy male Kurdish Iraqis randomly selected from a main regional premarital screening center in Northern Iraq were screened for G6PD deficiency using methemoglobin reduction test. The results were confirmed by quantitative enzyme assay for the cases that showed G6PD deficiency. DNA analysis was performed on 115 G6PD deficient subjects, 50 from the premarital screening group and 65 unrelated Kurdish male patients with documented acute hemolytic episodes due to G6PD deficiency. Analysis was performed using polymerase chain reaction/restriction fragment length polymorphism for five deficient molecular variants, namely G6PD Mediterranean (563 C→T), G6PD Chatham (1003 G→A), G6PD A- (202 G→A), G6PD Aures (143 T→C) and G6PD Cosenza (1376 G→C), as well as the silent 1311 (C→T) mutation.</p> <p>Results</p> <p>Among 580 random Iraqi male Kurds, 63 (10.9%) had documented G6PD deficiency. Molecular studies performed on a total of 115 G6PD deficient males revealed that 101 (87.8%) had the G6PD Mediterranean variant and 10 (8.7%) had the G6PD Chatham variant. No cases of G6PD A-, G6PD Aures or G6PD Cosenza were identified, leaving 4 cases (3.5%) uncharacterized. Further molecular screening revealed that the silent mutation 1311 was present in 93/95 of the Mediterranean and 1/10 of the Chatham cases.</p> <p>Conclusions</p> <p>The current study revealed a high prevalence of G6PD deficiency among Iraqi Kurdish population of Northern Iraq with most cases being due to the G6PD Mediterranean and Chatham variants. These results are similar to those reported from neighboring Iran and Turkey and to lesser extent other Mediterranean countries.</p

Evolutionary History of Helicobacter pylori Sequences Reflect Past Human Migrations in Southeast Asia

The human population history in Southeast Asia was shaped by numerous migrations and population expansions. Their reconstruction based on archaeological, linguistic or human genetic data is often hampered by the limited number of informative polymorphisms in classical human genetic markers, such as the hypervariable regions of the mitochondrial DNA. Here, we analyse housekeeping gene sequences of the human stomach bacterium Helicobacter pylori from various countries in Southeast Asia and we provide evidence that H. pylori accompanied at least three ancient human migrations into this area: i) a migration from India introducing hpEurope bacteria into Thailand, Cambodia and Malaysia; ii) a migration of the ancestors of Austro-Asiatic speaking people into Vietnam and Cambodia carrying hspEAsia bacteria; and iii) a migration of the ancestors of the Thai people from Southern China into Thailand carrying H. pylori of population hpAsia2. Moreover, the H. pylori sequences reflect iv) the migrations of Chinese to Thailand and Malaysia within the last 200 years spreading hspEasia strains, and v) migrations of Indians to Malaysia within the last 200 years distributing both hpAsia2 and hpEurope bacteria. The distribution of the bacterial populations seems to strongly influence the incidence of gastric cancer as countries with predominantly hspEAsia isolates exhibit a high incidence of gastric cancer while the incidence is low in countries with a high proportion of hpAsia2 or hpEurope strains. In the future, the host range expansion of hpEurope strains among Asian populations, combined with human motility, may have a significant impact on gastric cancer incidence in Asia

Molecular characterization of glucose-6-phosphate dehydrogenase deficient variants in Baghdad city - Iraq

Background: Although G6PD deficiency is the most common genetically determined blood disorder among Iraqis, its molecular basis has only recently been studied among the Kurds in North Iraq, while studies focusing on Arabs in other parts of Iraq are still absent. Methods: A total of 1810 apparently healthy adult male blood donors were randomly recruited from the national blood transfusion center in Baghdad. They were classified into G6PD deficient and non-deficient individuals based on the results of methemoglobin reduction test (MHRT), with confirmation of deficiency by subsequent enzyme assays. DNA from deficient individuals was studied using a polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) for four deficient molecular variants, namely G6PD Mediterranean (563 C®T), Chatham (1003 G®A), A- (202 G®A) and Aures (143 T®C). A subset of those with the Mediterranean variant, were further investigated for the 1311 (C®T) silent mutation. Results: G6PD deficiency was detected in 109 of the 1810 screened male individuals (6.0%). Among 101 G6PD deficient males molecularly studied, the Mediterranean mutation was detected in 75 cases (74.3%), G6PD Chatham in 5 cases (5.0%), G6PD A- in two cases (2.0%), and G6PD Aures in none. The 1311 silent mutation was detected in 48 out of the 51 G6PD deficient males with the Mediterranean variant studied (94.1%). Conclusions: Three polymorphic variants namely: the Mediterranean, Chatham and A-, constituted more than 80% of G6PD deficient variants among males in Baghdad. Iraq. This observation is to some extent comparable to othe

Biphenotypic acute leukemia: a report of two cases

We report two cases of biphenotypic acute leukaemia diagnosed in Hospital Universiti Kebangsaan Malaysia (HUKM), their clinical, haematological characteristics and response to chemotherapy. Both patients are middle-aged ladies who presented with hepatosplenomegaly and high white cell count, mainly composed of blast cells. Their bone marrow aspirations were hypercellular comprising of more than 90% heterogenous blast cells. Cytochemical analyses show more than 3% positivity towards peroxidase, with smaller blasts showing block positivity towards PAS. Immunophenotypically, the blasts showed dual expression of CD 33 and CD 19, CD 19 and CD34, intra CD22, intra TdT and intraMPO. One of the patients showed presence of the Philadelphia chromosome on cytogenetic analysis which was confirmed by Fluorecsence In Situ Hybridisation (FISH). Molecular analysis also showed presence of the BCR-ABL fusion protein. Both patients were given combination chemotherapy consisting of daunorubicin and cytosine arabinoside.However, the patient with positive Philadelphia chromosome BCR-ABL did not achieve morphological remission after induction chemotherapy. In view of the poor prognosis of this disease, both the patients were planned for upfront peripheral blood stem cell transplantatio

Detection of partial G6PD deficiency using OSMMR2000-D kit with Hb normalization.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide including Malaysia. Screening of cord blood for partial G6PD deficiency is important as they are also prone to develop acute haemolysis. In this study, we determined the prevalence of partial G6PD deficient in paediatric population aged 1 month-12 years and normal term female neonates using OSMMR-D kit with haemoglobin (Hb) normalization and compare it with florescence spot test (FST). A total of 236 children, aged between between 1 month-12 years and 614 normal term female neonates were recruited for this study. Determination of normal means for G6PD activity and; cut-off points for partial and severe deficiency were determined according to WHO Working Group (1989). Determination of prevalence for partial deficiency for both groups (female patient) was done using this enzyme assay kit and findings were compared with FST. In this study, 15.7% (18/115) female children were classified as partial G6PD deficient by quantitative enzyme method (G6PD activity: 4.23-5.26U/gHb). However, FST only detected 0.9% (1/115) with minimal G6PD activity. The prevalence of partial G6PD deficiency in female neonate group was 3.42% (21/614) by enzyme assay versus 0.49% (3/614) by FST. This study concluded that our routine screening method using FST was unable to diagnose female heterozygotes. We recommend using this quantitative enzyme assay method by OSMMR-D kit since it was more sensitive in detecting G6PD deficiency in female neonates compared to FST