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Vadolas J, Nualkaew T, Voon HPJ, Vilcassim S, Grigoriadis G. Interplay between α-thalassemia and β-hemoglobinopathies: Translating genotype-phenotype relationships into therapies. Hemasphere 2024; 8:e78. [PMID: 38752170 PMCID: PMC11094674 DOI: 10.1002/hem3.78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/22/2024] [Accepted: 04/11/2024] [Indexed: 05/18/2024] Open
Abstract
α-Thalassemia represents one of the most important genetic modulators of β-hemoglobinopathies. During this last decade, the ongoing interest in characterizing genotype-phenotype relationships has yielded incredible insights into α-globin gene regulation and its impact on β-hemoglobinopathies. In this review, we provide a holistic update on α-globin gene expression stemming from DNA to RNA to protein, as well as epigenetic mechanisms that can impact gene expression and potentially influence phenotypic outcomes. Here, we highlight defined α-globin targeted strategies and rationalize the use of distinct molecular targets based on the restoration of balanced α/β-like globin chain synthesis. Considering the therapies that either increase β-globin synthesis or reactivate γ-globin gene expression, the modulation of α-globin chains as a disease modifier for β-hemoglobinopathies still remains largely uncharted in clinical studies.
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Affiliation(s)
- Jim Vadolas
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Molecular and Translational SciencesMonash UniversityClaytonVictoriaAustralia
| | - Tiwaporn Nualkaew
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Present address:
Department of Medical Technology, School of Allied Health SciencesWalailak UniversityNakhon Si ThammaratThailand
| | - Hsiao P. J. Voon
- Department of Biochemistry and Molecular Biology, Cancer Program, Biomedicine Discovery InstituteMonash UniversityClaytonVictoriaAustralia
| | - Shahla Vilcassim
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- School of Clinical Sciences at Monash HealthMonash UniversityClaytonAustralia
| | - George Grigoriadis
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- School of Clinical Sciences at Monash HealthMonash UniversityClaytonAustralia
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Kumari A, Chauhan G, Chaudhuri PK, Kumari S, Prasad A. Genetic Variants Associated with the Risk of Stroke in Sickle Cell Anemia: Systematic Review and Meta-Analysis. Hemoglobin 2024; 48:101-112. [PMID: 38637280 DOI: 10.1080/03630269.2024.2340685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 04/01/2024] [Indexed: 04/20/2024]
Abstract
Sickle cell anemia (SCA) is the most common cause of stroke in children. As it is a rare disease, studies investigating the association with complications like stroke in SCD have small sample sizes. Here, we performed a systematic review and meta-analysis of the studies exploring an association of genetic variants with stroke to get a better indication of their association with stroke. PubMed and Google Scholar were searched to identify studies that had performed an association analysis of genetic variants for the risk of stroke in SCA patients. After screening of eligible studies, summary statistics of association analysis with stroke and other general information were extracted. Meta-analysis was performed using the fixed effect method on the tool METAL and forest plots were plotted using the R program. The random effect model was performed as a sensitivity analysis for loci where significant heterogeneity was observed. 407 studies were identified using the search term and after screening 37 studies that cumulatively analyzed 11,373 SCA patients were included. These 37 studies included a total of 2,222 SCA patients with stroke, predominantly included individuals of African ancestry (N = 16). Three of these studies performed whole exome sequencing while 35 performed single nucleotide-based genotyping. Though the studies reported association with 132 loci, meta-analyses could be performed only for 12 loci that had data from two or more studies. After meta-analysis we observed that four loci were significantly associated with risk for stroke: -α3.7 kb Alpha-thalassemia deletion (P = 0.00000027), rs489347-TEK (P = 0.00081), rs2238432-ADCY9 (P = 0.00085), rs11853426-ANXA2 (P = 0.0034), and rs1800629-TNF (P = 0.0003396). Ethnic representation of regions with a high prevalence of SCD like the Mediterranean basin and India needs to be improved for genetic studies on associated complications like stroke. Larger genome-wide collaborative studies on SCD and associated complications including stroke need to be performed.
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Affiliation(s)
- Aradhana Kumari
- Department of Genetics and Genomics, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
- Department of Biochemistry, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
| | - Ganesh Chauhan
- Department of Genetics and Genomics, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
- Central Research Facility, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
| | - Partha Kumar Chaudhuri
- Department of Paediatrics, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
| | - Sushma Kumari
- Department of Transfusion Medicine and Blood Centre, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
| | - Anupa Prasad
- Department of Genetics and Genomics, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
- Department of Biochemistry, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
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Santos B, Ginete C, Gonçalves E, Delgadinho M, Miranda A, Faustino P, Arez AP, Brito M. Characterization of a cohort of Angolan children with sickle cell anemia treated with hydroxyurea. Blood Cells Mol Dis 2024; 105:102822. [PMID: 38215581 DOI: 10.1016/j.bcmd.2023.102822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/26/2023] [Accepted: 12/28/2023] [Indexed: 01/14/2024]
Abstract
BACKGROUND Sickle Cell Anemia (SCA) is a monogenic disease, although its severity and response to treatment are very heterogeneous. OBJECTIVES This study aims to characterize a cohort of Angolan children with SCA and evaluate their response to hydroxyurea (HU) treatment and the potential side effects and toxicity. METHODS The study enrolled 215 patients between 3 and 12 years old before and after the administration of HU, at a fix dose of 20 mg/kg/day for 12 months. RESULTS A total of 157 patients started HU medication and 141 of them completed the 12-month treatment. After initiating HU treatment, the frequency of clinical events decreased (transfusions 53.4 %, hospitalizations 47.1 %). The response to HU medication varied among patients, with some experiencing an increase in fetal hemoglobin (HbF) of <5 %. The mean increase in HbF was 11.9 %, ranging from 1.8 % to 31 %. Responders to HU treatment were 57 %, inadequate responders 38.7 % and non-adherent 4.2 %. No clinical side effects related to HU were reported. Hematological toxicities were transient and reversible. Children naïve to HU and with lower HbF reported higher number of hospitalizations caused by malaria infection. During HU treatment, the frequency of malaria episodes did not appear to be affected by HbF levels. CONCLUSIONS the present study provided a valuable contribution to the understanding of the clinical and laboratory profiles of Angolan children with SCA. These findings support the evidence that the implementation of prophylactic measures and treatment with HU is associated with increased survival in children with SCA.
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Affiliation(s)
- Brígida Santos
- Centro de Investigação em Saúde de Angola (CISA), Caxito, Angola; Hospital Pediátrico David Bernardino (HPDB), Luanda, Angola; Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation Towards Global Health (LA-REAL), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisbon, Portugal
| | - Catarina Ginete
- H&TRC - Health & Technology Research Center, ESTeSL - Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Elisângela Gonçalves
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation Towards Global Health (LA-REAL), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisbon, Portugal
| | - Mariana Delgadinho
- H&TRC - Health & Technology Research Center, ESTeSL - Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - Armandina Miranda
- Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), Lisbon, Portugal
| | - Paula Faustino
- Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), Lisbon, Portugal; Instituto de Saúde Ambiental (ISAMB), Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal; Laboratório Associado TERRA, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Ana Paula Arez
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation Towards Global Health (LA-REAL), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisbon, Portugal
| | - Miguel Brito
- Centro de Investigação em Saúde de Angola (CISA), Caxito, Angola; H&TRC - Health & Technology Research Center, ESTeSL - Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal.
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Kirkham JK, Estepp JH, Weiss MJ, Rashkin SR. Genetic Variation and Sickle Cell Disease Severity: A Systematic Review and Meta-Analysis. JAMA Netw Open 2023; 6:e2337484. [PMID: 37851445 PMCID: PMC10585422 DOI: 10.1001/jamanetworkopen.2023.37484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/30/2023] [Indexed: 10/19/2023] Open
Abstract
Importance Sickle 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. Objective To 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 Sources PubMed, Web of Science, and Scopus were searched through May 16, 2023, identifying 5290 publications. Study Selection At 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 Synthesis Data 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 Measures Outcomes were aggregated into 25 categories, grouped as acute complications, chronic conditions, hematologic parameters or biomarkers, and general or mixed measures of SCD severity. Results The 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 Relevance The 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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Affiliation(s)
- Justin K. Kirkham
- Department of Oncology, St Jude Children’s Research Hospital, Memphis, Tennessee
| | - Jeremie H. Estepp
- Department of Hematology, St Jude Children’s Research Hospital, Memphis, Tennessee
- Department of Global Pediatric Medicine, St Jude Children’s Research Hospital, Memphis, Tennessee
- Now with Agios Pharmaceuticals, Cambridge, Massachusetts
| | - Mitch J. Weiss
- Department of Hematology, St Jude Children’s Research Hospital, Memphis, Tennessee
| | - Sara R. Rashkin
- Department of Hematology, St Jude Children’s Research Hospital, Memphis, Tennessee
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Santos EDC, Santana PVB, de Jesus LLS, Melo GIV, Yahouédéhou SCMA, da Guarda CC, Santiago RP, Fiuza LM, Carvalho SP, dos Santos LO, Adorno EV, Aleluia ACM, Luiz LCGC, Fonseca TCC, Gonçalves MDS, Aleluia MM. Leg Ulcers in Sickle Cell Disease: A Multifactorial Analysis Highlights the Hemolytic Profile. Hematol Rep 2023; 15:119-129. [PMID: 36810556 PMCID: PMC9945128 DOI: 10.3390/hematolrep15010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/12/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Sickle cell disease (SCD) is characterized by the presence of the variant S hemoglobin (HbS). The homozygous genotype (HbSS) is sickle cell anemia (SCA), while the double heterozygous of HbS and HbC (HbSC) is defined as SC hemoglobinopathy. The pathophysiology is based on chronic hemolysis, inflammation, endothelial dysfunction, and vaso-occlusion, which results in vasculopathy and serious clinical manifestations. Sickle leg ulcers (SLUs) are cutaneous lesions around the malleoli frequent in 20% of Brazilian patients with SCD. SLUs present a variable clinical and laboratory pattern modulated by several characteristics that are not fully understood. Hence, this study aimed to investigate laboratory biomarkers and genetic and clinical parameters associated with the development of SLUs. This descriptive cross-sectional study included 69 SCD patients, 52 without SLU (SLU-) and 17 with active or previous SLU history (SLU+). The results showed a higher incidence of SLU in SCA patients and there was no observed association of α-3.7 Kb thalassemia in SLU occurrence. Alterations in NO metabolism and hemolysis were associated with clinical evolution and severity of SLU, in addition to hemolysis modulating the etiology and recurrence of SLU. Our multifactorial analyses demonstrate and extend the role of hemolysis driving the pathophysiological mechanism of SLU.
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Affiliation(s)
- Edvan do Carmo Santos
- Laboratório de Patologia Aplicada e Genética, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Brazil
| | - Paulo Vinícius Bispo Santana
- Laboratório de Patologia Aplicada e Genética, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Brazil
| | - Laíne Lopes Silva de Jesus
- Laboratório de Patologia Aplicada e Genética, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Brazil
| | - Gabriela Imbassahy Valentim Melo
- Laboratório de Patologia Aplicada e Genética, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Brazil
| | | | - Caroline Conceição da Guarda
- Laboratório de Investigação em Genética e Hematologia Translacional, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Rayra Pereira Santiago
- Laboratório de Investigação em Genética e Hematologia Translacional, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Luciana Magalhães Fiuza
- Laboratório de Investigação em Genética e Hematologia Translacional, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Suéllen Pinheiro Carvalho
- Laboratório de Investigação em Genética e Hematologia Translacional, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Liz Oliveira dos Santos
- Centro de Ciência e Tecnologia em Energia e Sustentabilidade, Universidade Federal do Recôncavo da Bahia, Feira de Santana 44042-280, Brazil
| | - Elisângela Vitória Adorno
- Laboratório de Pesquisa em Anemias, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Salvador 40170-115, Brazil
| | | | | | | | - Marilda de Souza Gonçalves
- Laboratório de Investigação em Genética e Hematologia Translacional, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
- Centro de Ciência e Tecnologia em Energia e Sustentabilidade, Universidade Federal do Recôncavo da Bahia, Feira de Santana 44042-280, Brazil
| | - Milena Magalhães Aleluia
- Laboratório de Patologia Aplicada e Genética, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Brazil
- Correspondence: ; Tel.: +55-73-3680-5574
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Genetic modulation of anemia severity, hemolysis level, and hospitalization rate in Angolan children with Sickle Cell Anemia. Mol Biol Rep 2022; 49:10347-10356. [PMID: 36097125 DOI: 10.1007/s11033-022-07831-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/26/2022] [Accepted: 07/29/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND Sickle Cell Anemia (SCA) is a genetic disease caused by the c.20 A > T mutation in HBB gene, generally characterized by sickle erythrocytes, chronic hemolytic anemia, and vaso-occlusive events. This study aimed to investigate genetic modulators of anemia severity, chronic hemolytic rate, and clinical manifestations in pediatric SCA patients from Angola, where the disease is a severe public health problem. METHODS AND RESULTS The study was conducted on 200 SCA children living in Luanda or Caxito province. Their clinical phenotype was collected from patients' hospital records. Hematological and biochemical phenotypes were characterized in steady state condition. Twelve polymorphic regions in VCAM1, CD36 and NOS3 genes were genotyped using PCR, RFLP, and Sanger sequencing. CD36 gene promoter variants showed a significant impact on anemia severity. Particularly, the rs1413661_C allele was associated with lower hemoglobin levels, and increased number of hospitalizations and transfusions. This is the first report associating this SNP with SCA phenotypic heterogeneity. Moreover, the rs1041163_C allele in VCAM1 was associated with lower LDH levels; inversely the rs2070744_C allele in NOS3 was related with higher LDH levels and number of hospitalizations, being a risk factor for increased hemolytic rate. CONCLUSION This study highlights, for the first time in the Angolan population, the importance of the genetic modifiers of vascular cell adhesion and nitric oxide metabolism in SCA pediatric phenotypic variability.
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Costa-Júnior DAD, Santos APP, da Silva CM, Velloso-Rodrigues C. Growth Hormone/Insulin-Like Growth Factor 1 Axis Associated with Modifiers Factors in Children with Sickle Cell Anemia. Endocr Metab Immune Disord Drug Targets 2022; 22:954-962. [PMID: 35240969 DOI: 10.2174/1871530322666220303164029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/12/2021] [Accepted: 12/30/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Sickle cell anemia is a disease that develops episodes of acute pain and multiple organ dysfunction that can affect the growth hormone/insulin-like growth factor 1 (GH/IGF-1) axis. The severity of sickle cell anemia is influenced by modifying factors, such as levels of fetal hemoglobin (HbF), the co-inheritance of alpha-thalassemia, or treatment with hydroxyurea. METHODS This cross-sectional study in children with sickle cell anemia evaluated bone age (BA), adult height prediction (AHP) using BA, a target height (TH) calculated as the mean SDS of the parents, and laboratory parameters. Children were grouped according to serum levels of HbF, co-inheritance of alpha-thalassemia, and hydroxyurea therapy. RESULTS The mean age of the 39 children was 8.2±2.2 years old. The average height was -0.75±0.30 SDS, and 10.3% (4/39) had short stature. Adjusted levels of IGF-1 or IGFBP-3 were significantly higher in children with sickle cell anemia on hydroxyurea treatment, in children with HbF levels >10%, and in those without alpha-thalassemia. Using SDS, the growth potential of children with sickle cell anemia in relation to their parents, calculated by the difference between AHP and TH, as well as the difference between children's height and their TH, were lower in children with co-inheritance of alpha-thalassemia Conclusion: The study showed an association between modifying factors and the GH/IGF-1 axis in children with sickle cell anemia. Additionally, the co-inheritance of alpha-thalassemia was associated with decreased height in these children when adjusted for their parents' height.
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Affiliation(s)
- Domício Antônio da Costa-Júnior
- Department of Medicine, Life Sciences Institute, Federal University of Juiz de Fora, Governador Valadares, Minas Gerais, Brazil
| | | | | | - Cibele Velloso-Rodrigues
- Laboratory of Cellular Biology and Molecular Genetics, Department of Basic Life Sciences, Federal University of Juiz de Fora, Governador Valadares, Minas Gerais, Brazil
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Kirkham FJ, Lagunju IA. Epidemiology of Stroke in Sickle Cell Disease. J Clin Med 2021; 10:4232. [PMID: 34575342 PMCID: PMC8469588 DOI: 10.3390/jcm10184232] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022] Open
Abstract
Sickle cell disease is the most common cause of stroke in childhood, both ischaemic and haemorrhagic, and it also affects adults with the condition. Without any screening or preventative treatment, the incidence appears to fall within the range 0.5 to 0.9 per 100 patient years of observation. Newborn screening with Penicillin prophylaxis and vaccination leading to reduced bacterial infection may have reduced the incidence, alongside increasing hydroxyurea prescription. Transcranial Doppler screening and prophylactic chronic transfusion for at least an initial year has reduced the incidence of stroke by up to 10-fold in children with time averaged mean of the maximum velocity >200 cm/s. Hydroxyurea also appears to reduce the incidence of first stroke to a similar extent in the same group but the optimal dose remains controversial. The prevention of haemorrhagic stroke at all ages and ischaemic stroke in adults has not yet received the same degree of attention. Although there are fewer studies, silent cerebral infarction on magnetic resonance imaging (MRI), and other neurological conditions, including headache, epilepsy and cognitive dysfunction, are also more prevalent in sickle cell disease compared with age matched controls. Clinical, neuropsychological and quantitative MRI screening may prove useful for understanding epidemiology and aetiology.
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Affiliation(s)
- Fenella Jane Kirkham
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, Faculty of Population Health Sciences, 30 Guilford Street, London WC1N 1EH, UK
- Child Health, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton and University Hospital Southampton, Southampton SO16 6YD, UK
- Paediatric Neurosciences, King’s College Hospital, London SE5 9RS, UK
| | - Ikeoluwa A. Lagunju
- Department of Paediatrics, College of Medicine, University of Ibadan, Ibadan PMB 3017, Nigeria;
- Department of Paediatrics, University College Hospital, Ibadan PMB 5116, Nigeria
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Delgadinho M, Ginete C, Santos B, Miranda A, Brito M. Genotypic Diversity among Angolan Children with Sickle Cell Anemia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18105417. [PMID: 34069401 PMCID: PMC8158763 DOI: 10.3390/ijerph18105417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 11/16/2022]
Abstract
Background. Sickle cell anemia (SCA) is an inherited blood disorder that affects over 300,000 newborns worldwide every year, being particularly prevalent in Sub-Saharan Africa. Despite being a monogenic disease, SCA shows a remarkably high clinical heterogeneity. Several studies have already demonstrated the existence of some polymorphisms that can provide major clinical benefits, producing a mild phenotype. Moreover, the existence of distinct haplotypes can also influence the phenotype patterns of certain populations, leading to different clinical manifestations. Our aim was to assess the association between polymorphisms in genes previously related to SCA disease severity in an Angolan pediatric population. Methods. This study analyzed clinical and biological data collected from 192 Angolan children. Using NGS data, we classified the HBB haplotypes based on four previously described SNPs (rs3834466, rs28440105, rs10128556, and rs968857) and the genotype for the SNPs in HBG2 (rs7482144), BCL11A (rs4671393, rs11886868, rs1427407, rs7557939), HBS1L-MYB (rs66650371) and BGLT3 (rs7924684) genes. Results. The CAR haplotype was undoubtedly the most common HBB haplotype in our population. The HbF values and the ratio of gamma chains were statistically significant for almost all of the variants studied. We reported for the first time an association between rs7924684 in the BGLT3 gene and gamma chains ratio. Conclusions. The current findings emphasize the importance personalized medicine would have if applied to SCA patient care, since some of the variants studied might predict the phenotype and the overall response to treatment.
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Affiliation(s)
- Mariana Delgadinho
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal; (M.D.); (C.G.)
| | - Catarina Ginete
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal; (M.D.); (C.G.)
| | - Brígida Santos
- Centro de Investigação em Saúde de Angola (CISA), Caxito, Angola;
- Hospital Pediátrico David Bernardino (HPDB), Luanda 3067, Angola
| | - Armandina Miranda
- Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), 1649-016 Lisbon, Portugal;
| | - Miguel Brito
- H&TRC—Health & Technology Research Center, ESTeSL—Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal; (M.D.); (C.G.)
- Centro de Investigação em Saúde de Angola (CISA), Caxito, Angola;
- Correspondence: ; Tel.: +351-218980400
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