Hemoglobins in Togolese Newborns: Hb S, Hb C, Hb Bart's, and α-Globin Gene Status

Segbena, A.; Préhu, Claude; Wajcman, Henri; Bardakdjian‐Michau, Josiane; Messie, Kodjovi; Feteke, L; Vovor, Anne; David, Mireille; Feingold, Josué; Galactéros, Frédéric

doi:10.1002/(sici)1096-8652(199811)59:3<208::aid-ajh5>3.0.co;2-r

Cited by 24 publications

(7 citation statements)

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“…The expectation should be modified in the light of high levels of consanguinous marriage. In three different publications on neonatal screening in Togo, Ivory Coast and Burkina Faso, a relation of one to 15 is observed, [16][17][18] and consanguinity is probably partially responsible for this result. If this observation is applied to Rwanda, around one neonate per 600 births will be diagnosed with sickle cell disease.…”

Section: Discussionmentioning

confidence: 99%

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

et al. 2006

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Section: Discussionmentioning

confidence: 99%

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

et al. 2006

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“…The values usually used are those of Caucasian populations. In Togo, it is especially difficult to establish hematological reference values for RBC parameters because of the (i) high frequency of alpha-thalassemia (49.2%), (ii) beta-globin gene abnormalities (37.5%), [11], and, (iii) iron deficiency anemia in the overall population. …”

Section: Introductionmentioning

confidence: 99%

Hematological Reference Values for Healthy Adults in Togo

et al. 2011

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The hematological reference values are very important for diagnostic orientation and treatment decision. The aim of this study was to establish hematological reference values for healthy adults in Togo. A total of 2571 voluntary blood donors participated to this study. Only 1349 subjects negative for HIV, HBV, HCV, malaria, and without hemoglobin abnormalities in electrophoresis and hypochromia on blood smear, were definitively retained for the study. Median hemoglobin level was higher in males than females (15.1 g/dL versus 13.0 g/dL, p = 0.000). Median total WBC (4.2×109/L) and absolute neutrophil counts (1.6×109/L) were similar by gender. The median lymphocyte counts in males and females were, respectively, 2.1×109/L and 2.2×109/L (p = 0.11). The median platelet count was lower in males than females (236×109/L versus 247×109/L, p = 0.004). Our median values for RBC parameters differ from those of African countries probably because of our inclusion criteria which eliminate most cases with iron deficiency and/or thalassemia.

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“…These assays make use of the eight base length differences between the HBA1 and HBA2 genes. One limitation of these assays is that due to rearrangements of the α-globin genes, such as the African α2 Polymorphism or the α12 allele, this difference in length between the HBA1 and HBA2 genes can be absent [ 30 – 32 ]. Indeed, these polymorphisms are reported to be very common, with the African α2 Polymorphism reaching a frequency of up to 12 % in some African populations [ 30 ].…”

Section: Discussionmentioning

confidence: 99%

“…One limitation of these assays is that due to rearrangements of the α-globin genes, such as the African α2 Polymorphism or the α12 allele, this difference in length between the HBA1 and HBA2 genes can be absent [ 30 – 32 ]. Indeed, these polymorphisms are reported to be very common, with the African α2 Polymorphism reaching a frequency of up to 12 % in some African populations [ 30 ]. In contrast, GRACE-PCR is not affected by these gene rearrangements and it does not require the use of a capillary electrophoresis based genetic analyser making it a more universally applicable and faster screening method.…”

Section: Discussionmentioning

confidence: 99%

Development and validation of a high throughput, closed tube method for the determination of haemoglobin alpha gene (HBA1 and HBA2) numbers by gene ratio assay copy enumeration-PCR (GRACE-PCR)

2015

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BackgroundDeletions of the α-globin genes are the most common genetic abnormalities in the world. Currently multiplex Gap-PCRs are frequently used to identify specific sets of common deletions. However, these assays require significant post-amplification hands on time and cannot be used to identify novel or unexpected deletions. The aim of the current study was to develop a rapid screening test for the detection of all deletions of the α-globin genes that can be integrated into a high volume clinical laboratory workflow.MethodsA gene ratio assay copy enumeration (GRACE) PCR method was developed by simultaneous amplification of targets in the α-globin genes (HBA1 and HBA2) and the chloride channel voltage sensitive 7 (CLCN7) reference gene. A novel application of High Resolution Melting (HRM) analysis then allowed rapid determination of α-globin gene copy numbers. The assay was validated using 105 samples with previously determined and 62 samples with unknown α-globin genotypes.ResultsThe GRACE-PCR assay detected abnormal α-globin gene copy numbers in 108 of the 167 samples evaluated. The results were consistent with those from a commercial reverse hybridization assay and no allele drop out was observed.ConclusionsWe have successfully developed and validated a GRACE-PCR screening test for the detection of deletions and duplications of the α-globin genes. The assay is based on copy number determination and has the ability to detect both known and novel deletions of the α-globin genes. It is a closed tube technique; consequently the risk of amplicon contamination is negligible. Amplification, detection and analysis can be completed within one hour, making it faster, cheaper and simpler than other existing tests and thus well suited as a rapid first step in a clinical laboratory workflow.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-015-0258-y) contains supplementary material, which is available to authorized users.

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Hemoglobins in Togolese Newborns: Hb S, Hb C, Hb Bart's, and α-Globin Gene Status

Cited by 24 publications

References 9 publications

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

Hematological Reference Values for Healthy Adults in Togo

Development and validation of a high throughput, closed tube method for the determination of haemoglobin alpha gene (HBA1 and HBA2) numbers by gene ratio assay copy enumeration-PCR (GRACE-PCR)

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