scholarly journals Sickle hemoglobin: How critical are laboratory quality measures for accurate identification?

2021 ◽  
pp. 1-3
Author(s):  
Nazish Sana ◽  
Muhammad Shariq Shaikh ◽  
Admin
Keyword(s):  
Sickle Cell ◽  
Retention Time ◽  
Sickle Cell Trait ◽  
Globin Gene ◽  
Genetic Defect ◽  
Beta Globin ◽  
Globin Chain ◽  
Symptomatic Disease ◽  
Molecular Tests ◽  
The Impact

Madam, Adult haemoglobin (Hb) comprises of 2 alpha and 2 beta-globin chains, each having a haem molecule attached. In healthy individuals, around 95-98% HbA (?2?2) and 2–3.5% of Hb A2 (?2?2) are present. The genetic defect of globin chain in which valine is replaced for glutamic acid at position 6 of ? globin chain results in sickle haemoglobin (HbS). Homozygous genetic defect (?S?S) results in a symptomatic disease called 'sickle cell anaemia' whereas, heterozygous (??S) state is asymptomatic and commonly called as "sickle cell trait' [1]. On deoxygenation and dehydration, HbS undergoes irreversible polymerization causing deleterious effects in vivo [2]. Around 3.2 million people have sickle-cell disease worldwide, with about 80% cases in Africa. About 0.5 to 1 per cent of the Pakistani population carries HbS3. Currently, high-performance liquid chromatography (HPLC) is the preferred method in which HbS elutes at retention time ranging in between 4.1 to 4.7 minutes. Several other variant haemoglobins cause interference by co-eluting at same retention time include HbA2, Hb Q-Thailand, Hb Manitoba, Hb Russ, Hb Stanlivelly-II, HbE- Saskatoon, Hb Montgomery and many more[4]. Therefore, it is difficult to identify and differentiate HbS precisely from interfering variant haemoglobins for proper diagnosis and future genetic counselling of patients. The definitive test for this purpose is molecular detection of underlying mutation either by polymerase chain reaction (PCR) or sequencing of the beta-globin gene. Molecular tests, however, are expensive and require expertise. Therefore, these tests are not widely available in Pakistan and other resource constraint countries. World's leading quality assurance organizations such as College of American Pathologists (CAP) recommend that all cases found HbS positive in the primary screening should be confirmed by secondary testing [5], this can easily be achieved by sickling test. In the sickling test, the sample is combined with reducing agent (Sodium Met bisulfate) resulting in red cell hypoxia. Cells with HbS change to sickle shape from their normal biconcave shape, diagnosed by microscopic examination along with controls. This cost-effective and readily available technique helps to differentiate HbS from other variants. Therefore, every laboratory should confirm the presence of HbS by sickling test, and the government should ensure the availability of molecular tests at the mass level at a reduced cost supported by the efficient health insurance system. The impact of these strategies will provide accurate and timely diagnosis, Continuous...  

First reported duplication of the entire beta globin gene cluster causing an unusual sickle cell trait phenotype

2014 ◽  
Vol 170 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Claire Shooter ◽  
Tania Senior McKenzie ◽  
Matthew Oakley ◽  
Tracey Jacques ◽  
Barnaby Clark ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Globin Gene ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Globin Gene Cluster

scholarly journals Potential Impact of Sickle Hemoglobin Concentration on Survival Among Patients with Renal Medullary Carcinoma and Sickle Cell Trait

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4843-4843
Author(s):  
Marcus A. Carden ◽  
Jonathan Metts ◽  
John M. McCarty ◽  
Sarah Mitchell ◽  
Bradley Carthon ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Survival Data ◽  
Sickle Cell Trait ◽  
Case Reports ◽  
Globin Gene ◽  
Medullary Carcinoma ◽  
Exponential Relationship ◽  
Sickle Hemoglobin ◽  
Renal Medullary Carcinoma ◽  
Alpha Globin

Background: Renal medullary carcinoma (RMC) is a rare, aggressive form of renal cell carcinoma almost exclusively (>90%) diagnosed in individuals with sickle cell trait (SCT), and 2/3 of those affected are male. Based on population-surveillance data, only 246 patients were diagnosed with RMC between 2005-2014 (Carden etal. J Sickle Cell Disease and Hemoglobinopathies, 2018) and many patients have metastatic disease at diagnosis (Msaeoul et al., Clin Genitourin Cancer, 2019). Median overall survival (OS) in patients with metastatic RMC (mRMC) at diagnosis is less than 12 months and predictors of survival are largely unknown, although case reports suggest novel chemotherapeutic strategies are important (Carden et al., Ped Blood Cancer, 2017&2018). The role SCT plays in RMC pathobiology, however, is largely unknown, as many patients do not have a complete hemoglobin subtype profile completed at diagnosis. Studies evaluating sickle hemoglobin concentrations (%HbS) in relation to survival for patients with RMC are needed, as SCT is associated with renal dysfunction and researchers have hypothesized that HbS polymerization within red cells traversing the kidney disrupts blood perfusion, which leads to kidney injury and an increased possibility for cancer formation (Msaeoul et al, Clin Cancer Res, 2018). Patients with %HbS≤36%, such as patients with SCT and concomitant alpha-globin gene deletion(s) might be protected against HbS polymerization and renal concentrating defects (Gupta etal., J Clin Invest, 1991). We hypothesize that lower %HbS is associated with higher survival. In this preliminary multi-institutional study, we retrospectively reviewed available charts from patients diagnosed with mRMC and SCT to evaluate for an association between %HbS and OS. Methods: We found nine patients (3 adults, 6 children) who were diagnosed with mRMC and SCT at our various institutions between 2002-2017 who had survival data. Eight patients had %HbS levels by hemoglobin quantification at diagnosis. In a post-hoc analysis, patients were separated into two groups (%HbS>36% and %HbS≤36%), levels similar to that found in patients with alpha-globin gene deletions described by Gupta et al. Fit-curves were determined for OS vs. %HbS. Three-year OS was determined using Kaplan-Meier analysis and the log-rank method. P<0.05 was considered statistically significant. Results: Clinical characteristics of patients are shown in Table 1. Average age (standard deviation) at diagnosis was 15.2 years (4.9) and most patients were male (87.5%). Six patients had %HbS >36% and 2 patients had %HbS ≤36%. Median OS was 17.8 months. Using fit-function testing, analysis of survival vs. %HbS yielded an exponential relationship (R2=0.69), suggesting higher survival when %HbS≤36% (p=0.05). OS of the two patients with %HbS≤36% was greater than those with %HbS>36%, though results were not statistically significant (p = 0.09). Conclusion: While there are limitations to this small, retrospective analysis, these data suggest that lower intracellular red cell %HbS concentrations could be protective in patients with mRMC and SCT. Chemotherapy and other treatment regimens may also play a role in survival and need to be studied. Further investigation is needed to determine the role SCT plays in RMC pathobiology and to determine if %HbS concentrations, as well as alpha-thalassemia deletion(s), may be protective in patients with RMC. Disclosures Carden: GBT: Honoraria; NIH: Research Funding.

scholarly journals An analysis of fetal hemoglobin variation in sickle cell disease: the relative contributions of the X-linked factor, beta-globin haplotypes, alpha-globin gene number, gender, and age

Blood ◽  
1995 ◽  
Vol 85 (4) ◽  
pp. 1111-1117 ◽  
Author(s):  
YC Chang ◽  
KD Smith ◽  
RD Moore ◽  
GR Serjeant ◽  
GJ Dover
Keyword(s):  
Sickle Cell ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Globin Genes ◽  
Beta Globin ◽  
Gene Number ◽  
Cohort Group ◽  
Five Factors ◽  
F Cells ◽  
Alpha Globin

Five factors have been shown to influence the 20-fold variation of fetal hemoglobin (Hb F) levels in sickle cell anemia (SS): age, sex, the alpha-globin gene number, beta-globin haplotypes, and an X-linked locus that regulates the production of Hb F-containing erythrocytes (F cells), ie, the F-cell production (FCP) locus. To determine the relative importance of these factors, we studied 257 Jamaican SS subjects from a Cohort group identified by newborn screening and from a Sib Pair study. Linear regression analyses showed that each variable, when analyzed alone, had a significant association with Hb F levels (P < .05). Multiple regression analysis, including all variables, showed that the FCP locus is the strongest predictor, accounting for 40% of Hb F variation. beta-Globin haplotypes, alpha-globin genes, and age accounted for less than 10% of the variation. The association between the beta-globin haplotypes and Hb F levels becomes apparent if the influence of the FCP locus is removed by analyzing only individuals with the same FCP phenotype. Thus, the FCP locus is the most important factor identified to date in determining Hb F levels. The variation within each FCP phenotype is modulated by factors associated with the three common beta-globin haplotypes and other as yet unidentified factor(s).

scholarly journals Production of F cells in sickle cell anemia: regulation by a genetic locus or loci separate from the beta-globin gene cluster

Blood ◽  
1984 ◽  
Vol 64 (5) ◽  
pp. 1053-1058 ◽  
Author(s):  
SH Boyer ◽  
GJ Dover ◽  
GR Serjeant ◽  
KD Smith ◽  
SE Antonarakis ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Sickle Cell ◽  
Genetic Locus ◽  
Globin Gene ◽  
The United States ◽  
Beta Globin ◽  
Cell Production ◽  
Beta Globin Gene ◽  
Globin Gene Cluster ◽  
Sib Pairs

Abstract Levels of fetal hemoglobin (HbF) bearing reticulocytes (F reticulocytes) range from 2% to 50% in patients with sickle cell (SS) anemia. To learn whether any portion of such variation in F cell production is regulated by loci genetically separable from the beta- globin gene cluster, percentages of F reticulocytes were compared in 59 sib pairs composed solely of SS members, including 40 pairs from Jamaica and 19 from the United States. We reasoned that differences in F reticulocyte levels might arise (1) from any of several kinds of artifact, (2) via half-sib status, or (3) because one or more genes regulating F cell production segregate separately from beta S. We minimized the role of artifact by assay of fresh samples from 84 SS individuals, including both members of 38 sib pairs. In 78 of the 84 subjects, serial values for percent F reticulocytes fell within 99.9% confidence limits or were alike by t test (P greater than or equal to .05). This left 32 sib pairs for which F reticulocyte levels in each member were reproducible. When sib-sib comparisons were limited to these 32 pairs, percentages of F reticulocytes were grossly dissimilar within 12 Jamaican and 3 American sibships. Within them, the probability that sibs were alike was always less than or equal to .005 and usually less than or equal to 10(-4). We next minimized the contribution of half-sibs among Jamaicans by a combination of paternity testing and sib-sib comparison of beta-globin region DNA restriction fragment length polymorphisms, especially among discordant pairs. We thereafter concluded that at least seven to eight Jamaican pairs were composed of reproducibly discordant full sibs. There is thus little doubt that there are genes regulating between-patient differences in F cell production that are separate from the beta-globin gene cluster. Still unanswered is (1) whether or not these genes are actually linked to beta S, (2) why F reticulocyte levels in Americans tend to be lower than in Jamaicans, and (3) whether or not differences in F cell production among SS patients are regulated by several major loci or by only one.

Globin Chain Synthesis in Sickle Cell Trait Under Conditions of Folate Antagonism

1974 ◽  
Vol 51 (4) ◽  
pp. 236-239 ◽  
Author(s):  
George R. Honig ◽  
George Mason ◽  
Loyda N. Vida
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Globin Chain ◽  
Chain Synthesis ◽  
Globin Chain Synthesis

Cell Free Fetal and Total DNA Levels in Pregnancies at Risk of Sickle Cell Disease and Significant Ethnic Variation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3791-3791
Author(s):  
Ageliki Gerovassili ◽  
Kypros H. Nicolaides ◽  
Swee Lay Thein ◽  
David Rees
Keyword(s):  
At Risk ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Globin Gene ◽  
Cell Disease ◽  
Maternal Weight ◽  
Chromosome 11 ◽  
Significant Difference ◽  
African Caribbean

Abstract Cell free (cf) DNA in maternal circulation is increasingly investigated in pregnancy. We aimed to determine if sickle cell trait women had quantitative differences of cfDNA with controls and if there was an ethnic difference between the cfDNA levels of Northern European and African/African-Caribbean populations. Non-invasive prenatal diagnosis through quantification of fetal and total cfDNA was tested in 33 pregnant women at risk of carrying a fetus affected with sickle cell disease and 124 control pregnancies. Fetal cfDNA assays were based on two Y chromosome specific markers (SRY and DYS14) and total cfDNA was based on the β-globin gene on chromosome 11. Maternal age (MA), gestation age (GA), fetal sex, storage time prior to extraction, maternal weight and body mass index (BMI) before pregnancy were compared to the fetal and total cfDNA levels. No significant difference in the fetal or total cfDNA levels was found between any of the control pregnancies and the sickle cell trait mothers carrying HbAA, HbAS and HbSS fetuses. However, higher levels of total cfDNA, but lower fetal cfDNA levels were observed in the African/African-Caribbean population compared with the Nothern Europeans. A significant variation in cfDNA was found between ethnic groups, which should be taken under consideration in future studies measuring cfDNA.

A Novel β Globin Gene Mutation, Reported As An α Chain Hemoglobin Variant By High Performance Liquid Chromatography (HPLC) & As Sickle Cell Trait On New Born Screening: A case Report

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 954-954
Author(s):  
Kranthi Nandan Seelaboyina ◽  
Jennifer Alison Busse ◽  
Sandeep Malik ◽  
Thomas Moulton
Keyword(s):  
Sickle Cell ◽  
Copy Number ◽  
Sickle Cell Trait ◽  
Globin Gene ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Thalassemia Intermedia ◽  
Exon 2 ◽  
Alpha Globin ◽  
Hemoglobin Variants

Abstract Introduction There are 827 variants of β thalassemia reported to the registry of human hemoglobin variants and thalassemias registry 1. Genetic mutations of β thalassemia are very diverse but can be broadly divided in to non deletion forms and deletion forms. The new mutation is a frame shift insertion in exon 2 of the β globin gene. To the best of our knowledge this mutation has never been described before and presents as a mild form β thalassemia intermedia. Objective To describe the phenotypic presentation of the new β globin variant, due to insertion of 9 nucleotides (AAAGTGCTC) between nucleotides c.207 and c.208. Case report A 22 months-old Hispanic boy who was referred for evaluation of persistent anemia. The new born screening for the child was positive for sickle cell trait. Initial hemoglobin (Hb) was 8.8, hematocrit was 27 and MCV was 65.5, which were decreased. RDW was 25.2, which was increased. Hemoglobin evaluation by acid and alkaline electrophoresis and HPLC revealed a HbS 0%, HbF 6.5% HbA 78.4%, HbA2 4.9% and a Hb variant 10.2%. The interpretation of the results was an α globin variant suggestive of Hb Montefiore and β thalassemia trait. Alpha thalassemia PCR for the 7 most common deletions in the α globin chain was negative. Subsequent α globin gene sequencing revealed no α globin gene mutations. On physical exam there were no bony changes or hepatosplenomegaly. Family History The mother is 29-year-old with HbAA. The father is 39-years-old with the same mutation on beta globin gene analysis. Hb electrophoresis also suggested an α and β globin mutation. Alpha thalassemia PCR was negative and he had a normal α globin gene copy number. At age 19 he had a splenectomy secondary to splenomegaly and hypersplenism. He is consistently anemic with Hb< 9 and MCV < 70. The child has a paternal half brother, who is 21 years old and has similar problems as father. He had a splenectomy at the age of 17 after admission for abdominal pain. The patient has a 5-year-old sibling, who is normal with HbAA and another paternal half sibling reported as no anemia. Discussion Though β thalassemia intermedia is most commonly homozygous or compound heterozygous, less frequently it can be due to single locus mutation. DNA sequencing of the α globin gene of the index case was completely normal and there was normal copy number of the α globin gene in the father. No Hb S was found on Hb electrophoresis. The new mutation adds 9 base pairs to exon 2 and 3 amino acids (Lys-Val-Leu) between amino acid 68 and 69 of the protein. This elongates the beta chain which can lead to instability and precipitation of Hb as well as hemolysis and anemia2. Further studies like short time incubation and pulse chase globin chain synthesis experiments are needed to know the stability of the β globin protein3. In addition, an increase of α globin gene copy number can also be a reason for increasing the severity of β thalassemia trait2. However the α gene copy was normal in the father. Conclusion We present a case of a child with a false positive abnormal newborn screen suggestive of sickle cell trait, as well as a Hb electrophoresis suggestive of an alpha globin mutation. As the father and paternal brother have had a splenectomy in their teen years with noted hepatosplenomegaly, suggestive of increased hemolysis, and the anemia is more severe than usual for β thalassemia trait, this suggests that phenotypically the c.199_207dup variant presents as a mild β thalassemia intermedia. In addition, there does not seem to be any bony abnormalities associated with marrow hyperplasia. As both our patients are heterozygous for this novel mutation with normal α globin gene copy number and alpha globin sequencing, we suspect that elongation of the β globin produces an unstable hemoglobin with a mild β thalassemia intermedia phenotype2. References 1. Databases of human hemoglobin variants and other resources at the globin gene server. Hemoglobin. 25(2):183-93, 2001 May. 2. Galanello R, Cao A. Relationship between genotype and phenotype. Thalassemia intermedia. Annals of the New York Academy of Sciences 1998; 850:325-33. 3. Is hemoglobin instability important in the interaction between hemoglobin E and beta thalassemia? Blood September 15, 1998 vol. 92 no. 6 2141-2146. Disclosures: No relevant conflicts of interest to declare.

Beta-Globin Gene Cluster Haplotypes in Yemeni Children with Sickle Cell Disease

2010 ◽  
Vol 123 (3) ◽  
pp. 182-185 ◽  
Author(s):  
Abdul-Wahab M. Al-Saqladi ◽  
Bernard J. Brabin ◽  
Hassan A. Bin-Gadeem ◽  
Warsha A. Kanhai ◽  
Marion Phylipsen ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Gene Cluster ◽  
Sickle Cell ◽  
Globin Gene ◽  
Beta Globin ◽  
Cell Disease ◽  
Beta Globin Gene ◽  
Globin Gene Cluster
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