Atypical β-S haplotypes: classification and genetic modulation in patients with sickle cell anemia

Okumura, Jéssika Viviani; Silva, Danilo G. H.; Torres, Lidiane de Souza; Junior, Edis Belini; Venâncio, Larissa Paola Rodrigues; Carrocini, Gisele C S; Nascimento, Patrícia Pereira do; Lobo, Clarisse; Bonini-Domingos, Cláudia Regina

doi:10.1038/s10038-018-0554-4

Cited by 6 publications

(2 citation statements)

References 29 publications

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“…However, there is also a large proportion of atypical haplotypes in this cohort, which may be indicative of a genetically heterogeneous population that may have high levels of admixture or be a site of early migration. In fact, atypical haplotypes not belonging to the 5 most common ones (Senegalese, Benin, Bantu, Cameroon, Arab), have been described in other populations (Brazil, Nigeria, India) and could be responsible for the extreme phenotypic diversity of SCD ( 34 – 36 ). Future genetic studies are needed in this field.…”

Section: Discussionmentioning

confidence: 99%

Distribution of HbS Allele and Haplotypes in a Multi-Ethnic Population of Guinea Bissau, West Africa: Implications for Public Health Screening

et al. 2022

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BackgroundSickle Cell Disease (SCD) is an inherited condition that is widespread globally and especially in malaria-endemic West African countries. Limited epidemiological data on SCD are available for Guinea Bissau, where newborn screening is not yet implemented, routine diagnosis is not available, and care is case directed.MethodsDried blood spots were collected from children accessing two hospitals managed by Italian Non-Governmental Organizations in the capital city of Bissau and sent to Padova for Hemoglobin (Hb) quantification through HPLC and molecular analysis. Beta globin gene analysis was performed in all; and Hb haplotype of the HbSS and HbSA patients was performed in South Africa. One hundred samples belonging to the most frequent ethnic groups were randomly selected for detection of G6PD mutations.ResultsSamples from 848 consecutive children (498 males and 350 females, mean age 6.8 years) accessing the two hospitals were analyzed: 6.95% AS (4.42% allelic frequency), 0.94% SS, and 0.23% AC. 376G G6PD allelic frequency was 24%; 14.8% in AS individuals. The Senegal haplotype was the most prevalent (31%), and the proposition of chromosomes with the atypical haplotype was surprisingly high (56%).ConclusionOur study demonstrates a significant frequency of the HbS allele in the population of Guinea Bissau supporting the implementation of screening strategies. The differences among ethnic groups can help guide targeted interventions for SCD awareness campaigns and determine priority areas for public health interventions. The pilot analysis on haplotypes reveals a large proportion of the atypical haplotype, which may be indicative of a genetically heterogeneous population.

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Section: Discussionmentioning

confidence: 99%

Distribution of HbS Allele and Haplotypes in a Multi-Ethnic Population of Guinea Bissau, West Africa: Implications for Public Health Screening

et al. 2022

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“…An atypical haplotype is one caused by recombination of common ones, meaning they are arranged into separated block-like structures, over the human genome [ 31 ]. The current study revealed a general absence of the S (sickle) gene among 94.9% of patients from Xmn1 ′5 to G γ (Figures 1 and 2 ).…”

Section: Discussionmentioning

confidence: 99%

Molecular Analysis of Xmn1-Polymorphic Site ´5 to Gγ of the β-Globin Gene Cluster in a Saudi Population of Jazan Region in Correlation with Hb F Expression

Elderdery

Alsrhani

Alzahrani

et al. 2022

Evidence-Based Complementary and Alternative Medicine

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The southern part of Saudi Arabia has an ethnically diverse population where sickle-cell anemia (sickle cell disease) is common, but little is known about its βs haplotypes. The goal of the current study is to ascertain the prevalence of the Hb S gene with analysis of Xmn1 ′5 to Gγ haplotype among the Saudi population in the Jazan area. Initially recorded findings of (1) Hb S gene and (2) hematological parameters with Hb F levels were collected from 5990 participants. Then, the second series of 70 different patients with established sickling disease and 30 healthy individuals as a control group was recruited, in which the genotype of Xmn1 ′5 to Gγ-SNP was performed by PCR-RFLP. In the first series, the prevalence of Hb types was AA at 86.8% (N = 5198), AS at 12.4% (N = 745), and SS at 0.8% (N = 47). Of the second series, three patients (4.3%) were (±) Xmn1 ′5 to Gγ and 67 (95.7%) were (−/−) in Xmn1 ′5 to Gγ. In the controls, the (±) Xmn1 ′5 to Gγ was observed in only one individual (3.3%), aged 30. These findings possibly represent a new Saudi haplotype, [±] Xmn1 ′5 to Gγ. Our results demonstrate that most patients with SCD in Jazan have [−/−] Xmn1 with higher levels of Hb F and positive Xmn1 ′5 to Gγ normally associated with a low level of Hb F.

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Genetic Variation and Sickle Cell Disease Severity

Kirkham,

Estepp,

Weiss

et al. 2023

JAMA Netw Open

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ImportanceSickle cell disease (SCD) is a monogenic disorder, yet clinical outcomes are influenced by additional genetic factors. Despite decades of research, the genetics of SCD remain poorly understood.ObjectiveTo assess all reported genetic modifiers of SCD, evaluate the design of associated studies, and provide guidelines for future analyses according to modern genetic study recommendations.Data SourcesPubMed, Web of Science, and Scopus were searched through May 16, 2023, identifying 5290 publications.Study SelectionAt least 2 reviewers identified 571 original, peer-reviewed English-language publications reporting genetic modifiers of human SCD phenotypes, wherein the outcome was not treatment response, and the comparison was not between SCD subtypes or including healthy controls.Data Extraction and SynthesisData relevant to all genetic modifiers of SCD were extracted, evaluated, and presented following STREGA and PRISMA guidelines. Weighted z score meta-analyses and pathway analyses were conducted.Main Outcomes and MeasuresOutcomes were aggregated into 25 categories, grouped as acute complications, chronic conditions, hematologic parameters or biomarkers, and general or mixed measures of SCD severity.ResultsThe 571 included studies reported on 29 670 unique individuals (50% ≤ 18 years of age) from 43 countries. Of the 17 757 extracted results (4890 significant) in 1552 genes, 3675 results met the study criteria for meta-analysis: reported phenotype and genotype, association size and direction, variability measure, sample size, and statistical test. Only 173 results for 62 associations could be cross-study combined. The remaining associations could not be aggregated because they were only reported once or methods (eg, study design, reporting practice) and genotype or phenotype definitions were insufficiently harmonized. Gene variants regulating fetal hemoglobin and α-thalassemia (important markers for SCD severity) were frequently identified: 19 single-nucleotide variants in BCL11A, HBS1L-MYB, and HBG2 were significantly associated with fetal hemoglobin (absolute value of Z = 4.00 to 20.66; P = 8.63 × 10−95 to 6.19 × 10−5), and α-thalassemia deletions were significantly associated with increased hemoglobin level and reduced risk of albuminuria, abnormal transcranial Doppler velocity, and stroke (absolute value of Z = 3.43 to 5.16; P = 2.42 × 10−7 to 6.00 × 10−4). However, other associations remain unconfirmed. Pathway analyses of significant genes highlighted the importance of cellular adhesion, inflammation, oxidative and toxic stress, and blood vessel regulation in SCD (23 of the top 25 Gene Ontology pathways involve these processes) and suggested future research areas.Conclusions and RelevanceThe findings of this comprehensive systematic review and meta-analysis of all published genetic modifiers of SCD indicated that implementation of standardized phenotypes, statistical methods, and reporting practices should accelerate discovery and validation of genetic modifiers and development of clinically actionable genetic profiles.

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Atypical β-S haplotypes: classification and genetic modulation in patients with sickle cell anemia

Cited by 6 publications

References 29 publications

Distribution of HbS Allele and Haplotypes in a Multi-Ethnic Population of Guinea Bissau, West Africa: Implications for Public Health Screening

Distribution of HbS Allele and Haplotypes in a Multi-Ethnic Population of Guinea Bissau, West Africa: Implications for Public Health Screening

Molecular Analysis of Xmn1-Polymorphic Site ´5 to Gγ of the β-Globin Gene Cluster in a Saudi Population of Jazan Region in Correlation with Hb F Expression

Genetic Variation and Sickle Cell Disease Severity

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