Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 91
Filtrar
2.
Am J Trop Med Hyg ; 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33350369

RESUMO

Human genetics research and applications are rapidly growing areas in health innovations and services. African populations are reported to be highly diverse and carry the greatest number of variants per genome. Exploring these variants is key to realize the genomic medicine initiative. However, African populations are grossly underrepresented in various genomic databases, which has alerted scientists to address this issue with urgency. In Tanzania, human genetics research and services are conducted in different institutions on both communicable and noncommunicable diseases. However, there is poor coordination of the research activities, often leading to limited application of the research findings and poor utilization of available resources. In addition, contributions from Tanzanian human genetics research and services are not fully communicated to the government, national, and international communities. To address this scientific gap, the Tanzania Society of Human Genetics (TSHG) has been formed to bring together all stakeholders of human genetics activities in Tanzania and to formally bring Tanzania as a member to the African Society of Human Genetics. This article describes the inauguration event of the TSHG, which took place in November 2019. It provides a justification for its establishment and discusses presentations from invited speakers who took part in the inauguration of the TSHG.

3.
BMC Health Serv Res ; 20(1): 1141, 2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33317526

RESUMO

BACKGROUND: Monitoring patient's clinical attendance is a crucial means of improving retention in care and treatment programmes. Sickle cell patients' outcomes are improved by participation in comprehensive care programmes, but these benefits cannot be achieved when patients are lost from clinical care. In this study, patients are defined as loss to follow-up when they did not attend clinic for more than 9 months. Precise information on the retention rate and characteristics of those who are not following their clinic appointments is needed to enable the implementation of interventions that will be effective in increasing the retention to care. METHOD: This was a retrospective study involving sickle cell patients registered in the Muhimbili Sickle Cohort in Tanzania. Descriptive and survival analysis techniques both non-parametric methods (Kaplan-Meier estimator and Log-rank test) and semi-parametric method (Cox's proportional hazard model), were used. A p-value of 0.05 was considered significant to make an inference from the analysis. RESULTS: A total of 5476 patients were registered in the cohort from 2004 to 2016. Of these, 3350 (58.13%) were actively participating in clinics, while 2126 (41.87%) were inactive, of which 1927 (35.19%) were loss to follow-up. We used data from 2004 to 2014 because between 2015 and 2016, patients were referred to other government hospitals. From the survival analysis results, pediatric (HR: 14.29,95% CI: 11.0071-18.5768, p <  0.001) and children between 5 and 17 years [HR:2.61,95% CI:2.2324-3.0705, p <  0.001] patients were more likely to be loss to follow-up than the adult (18 and above years) patients. It was found that patients with above averages for hematocrit (HR: 2.38, 95% CI: 1.0076-1.0404, p = 0.0039) or mean cell volume (HR: 4.28, (95% CI: 1.0260-1.0598, p < 0.001) were more likely to be loss to follow-up than their counterparts. CONCLUSION: Loss to follow-up is evident in the cohort of patients in long term comprehensive care. It is, therefore, necessary to design interventions that improve patients' retention. Suggested solutions include refresher training for health care workers and those responsible for patient follow-up on techniques for retaining patients and comprehensive transition programs to prepare patients who are moving from pediatric to adult clinics.

4.
Lancet Haematol ; 7(12): e902-e911, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33242447

RESUMO

Sickle cell disease is one of the most common, life-threatening, non-communicable diseases in the world and a major public health problem. Following the implementation of simple preventive and therapeutic modalities, infant mortality has almost been abolished in high-income countries, but only a small amount of progress has been made in improving survival in adulthood. Progressive end-organ damage, partly related to a systemic vasculopathy, is increasingly recognised. With the availability of a variety of novel disease-modifying drugs, gene addition and gene editing strategies, matched sibling donor haematopoietic stem cell transplantation (HSCT) in children (offering an overall survival rate of 95% and an event-free survival rate of 92%), and encouraging outcomes after alternative donor HSCT, the new challenge is to risk stratify patients, revise transplantation indications, and define the best therapeutic approach for each patient. The ultimate challenge will be to enable these advances in low-income and middle-income countries, where disease prevalence is highest and where innovative strategies are most needed.


Assuntos
Anemia Falciforme/terapia , Edição de Genes/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Condicionamento Pré-Transplante/métodos , Anemia Falciforme/patologia , Humanos
5.
OMICS ; 24(10): 559-567, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33021900

RESUMO

Sickle cell disease (SCD) is one of the most common blood disorders impacting planetary health. Over 300,000 newborns are diagnosed with SCD each year globally, with an increasing trend. The sickle cell disease ontology (SCDO) is the most comprehensive multidisciplinary SCD knowledge portal. The SCDO was collaboratively developed by the SCDO working group, which includes experts in SCD and data standards from across the globe. This expert review presents highlights and lessons learned from the fourth SCDO workshop that marked the beginning of applications toward planetary health impact, and with an eye to empower and cultivate multisite SCD collaborative research. The workshop was organized by the Sickle Africa Data Coordinating Center (SADaCC) and attended by 44 participants from 14 countries, with 2 participants connecting remotely. Notably, from the standpoint of democratizing and innovating scientific meeting design, an SCD patient advocate also presented at the workshop, giving a broader real-life perspective on patients' aspirations, needs, and challenges. A major component of the workshop was new approaches to harness SCDO to harmonize data elements used by different studies. This was facilitated by a web-based platform onto which participants uploaded data elements from previous or ongoing SCD-relevant research studies before the workshop, making multisite collaborative research studies based on existing SCD data possible, including multisite cohort, SCD global clinical trials, and SCD community engagement approaches. Trainees presented proposals for systematic literature reviews in key SCD research areas. This expert review emphasizes potential and prospects of SCDO-enabled data standards and harmonization to facilitate large-scale global SCD collaborative initiatives. As the fields of public and global health continue to broaden toward planetary health, the SCDO is well poised to play a prominent role to decipher SCD pathophysiology further, and co-design diagnostics and therapeutics innovation in the field.

6.
Br J Haematol ; 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-33073380

RESUMO

Patients with sickle cell disease (SCD) with high fetal haemoglobin (HbF) tend to have a lower incidence of complications and longer survival due to inhibition of deoxyhaemoglobin S (HbS) polymerisation by HbF. HbF-containing cells, namely F cells, are strongly influenced by genetic factors. We measured the percentage of F cells (Fcells%) in 222 patients with SCD to evaluate the association of (i) Fcells% with genetic HbF-modifier variants and (ii) Fcells% with haematological parameters. There was a different distribution of Fcells% in females compared to males. The association of the B-cell lymphoma/leukaemia 11A (BCL11A) locus with Fcells% (ß = 8·238; P < 0·001) and with HbF% (ß = 2·490; P < 0·001) was significant. All red cell parameters except for Hb and mean corpuscular Hb concentration levels in males and females were significantly different. The Fcells% was positively associated with mean cell Hb, mean cell volume and reticulocytes. To explain the significant gender difference in Fcells%, we tested for associations with single nucleotide polymorphisms on the X chromosomal region Xp22.2, where a genetic determinant of HbF had been previously hypothesised. We found in males a significant association with a SNP in FERM and PDZ domain-containing protein 4 (FRMPD4) and adjacent to male-specific lethal complex subunit 3 (MSL3). Thus, we have identified an X-linked locus that could account for a significant fraction of the Fcells% variation in patients with SCD.

10.
J Community Genet ; 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32789668

RESUMO

Introducing newborn screening (NBS) services for sickle cell disease (SCD) in Africa has been proven to be one of the most cost-effective approach to reducing morbidity and mortality associated with this condition. In view of this evidence, efforts have been made by countries in Africa where SCD prevalence is high to pilot NBS programmes and to strengthen comprehensive care services for SCD. While it is important to reap the benefits of NBS for SCD in Africa in terms of overall quantitative measures, it is also important to understand how certain social and cultural conditions may disproportionately influence the outcomes of screening for some groups. The aim of this study was to analyse the role of gender norms before and after NBS for SCD in Tanzania, and to assess how they influence the quality of care of diagnosed children. Using qualitative methods, we did in-depth interviews with families of children with SCD identified through the NBS services and focus group sessions with nurses working in neonatal and postnatal sections of regional referral hospitals in Dar es Salaam. By analysing the experiences of both the families and nurses, we were able to provide evidence on, firstly, the gendered relations that undergird childcare and, secondly, how those relations influence the quality of care the child may potentially receive. The results emphasize the importance of studying the social implications of SCD in Africa, especially with regard to improving the quality of care for patients with SCD in the region. We propose simple interventions, including gender-conscious health education and genetic counselling, which can help to improve the community understanding of genetic diseases while also reducing gender-related inequalities related to SCD care in Africa.

11.
BMC Med Ethics ; 21(1): 48, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32532327

RESUMO

BACKGROUND: Low literacy of study participants in Sub - Saharan Africa has been associated with poor comprehension during the consenting process in research participation. The concerns in comprehension are far greater when consenting to participate in genomic studies due to the complexity of the science involved. While efforts are made to explore possibilities of applying genomic technologies in diseases prevalent in Sub Saharan Africa, we ought to develop methods to improve participants' comprehension for genomic studies. The purpose of this study was to understand different approaches that can be used to seek consent from individuals with low literacy in Sub-Saharan African countries in genomic research to improve comprehension. METHODS: Using qualitative study design, we conducted focus-group discussions, in-depth interviews and participant observations as data collection methods. This study was embedded in a hospital based genomic study on Sickle Cell Disease at Muhimbili National Hospital in Tanzania. Thematic content analysis was used to analyse the transcripts and field notes. RESULTS: Findings from this study show that literacy level has little influence on understanding the research details. According to the participants of this study, the methods used to provide information, the language, and time spent with the study participants were the key factors influencing understanding. The availability of group sessions held before individual consent to allow for a detailed questions and answers format was agreed to be the best method to facilitate the comprehension. CONCLUSION: The quality of the consenting process of participants will be influence by a number of factors. The type of research consented for, where the research will be implemented and who are the potential study participants are amongst the factors that need to be assessed during the consenting. Measures to improve participants' comprehension need to be developed when consenting participants with low literacy level in genomic studies.

12.
BMC Med Genet ; 21(1): 125, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503527

RESUMO

BACKGROUND: Sickle cell disease (SCD) is a blood disorder caused by a point mutation on the beta globin gene resulting in the synthesis of abnormal hemoglobin. Fetal hemoglobin (HbF) reduces disease severity, but the levels vary from one individual to another. Most research has focused on common genetic variants which differ across populations and hence do not fully account for HbF variation. METHODS: We investigated rare and common genetic variants that influence HbF levels in 14 SCD patients to elucidate variants and pathways in SCD patients with extreme HbF levels (≥7.7% for high HbF) and (≤2.5% for low HbF) in Tanzania. We performed targeted next generation sequencing (Illumina_Miseq) covering exonic and other significant fetal hemoglobin-associated loci, including BCL11A, MYB, HOXA9, HBB, HBG1, HBG2, CHD4, KLF1, MBD3, ZBTB7A and PGLYRP1. RESULTS: Results revealed a range of genetic variants, including bi-allelic and multi-allelic SNPs, frameshift insertions and deletions, some of which have functional importance. Notably, there were significantly more deletions in individuals with high HbF levels (11% vs 0.9%). We identified frameshift deletions in individuals with high HbF levels and frameshift insertions in individuals with low HbF. CHD4 and MBD3 genes, interacting in the same sub-network, were identified to have a significant number of pathogenic or non-synonymous mutations in individuals with low HbF levels, suggesting an important role of epigenetic pathways in the regulation of HbF synthesis. CONCLUSIONS: This study provides new insights in selecting essential variants and identifying potential biological pathways associated with extreme HbF levels in SCD interrogating multiple genomic variants associated with HbF in SCD.


Assuntos
Anemia Falciforme/genética , Hemoglobina Fetal/genética , Variação Genética , Adolescente , Criança , Pré-Escolar , Redes Reguladoras de Genes , Humanos , Mutação com Perda de Função/genética , Tanzânia , Adulto Jovem
13.
Malar J ; 19(1): 165, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32334583

RESUMO

BACKGROUND: Patients with sickle cell disease (SCD), an inherited haemoglobinopathy, have increased risk of malaria, at least in part due to impaired splenic function. Infection with Plasmodium falciparum in SCD patients can trigger painful vaso-occlusive crisis, increase the severity of anaemia, and contribute to early childhood mortality. CASE PRESENTATION: A 17 year-old Tanzanian male with known SCD was admitted to Muhimbili National Hospital, a tertiary referral centre in Dar-es-Salaam, following an attack of malaria. From 2004 to 2007 the patient had lived in USA, and from 2010 to 2016 in France where, on account of hypersplenism and episodes of splenic sequestrations, in 2014 the spleen was removed. After appropriate clinical and laboratory assessment the patient was re-started on hydroxyurea; and anti-malarial-prophylaxis with proguanil was instituted. The patient has remained well and malaria-free for the following 15 months. CONCLUSION: SCD patients are highly vulnerable to malaria infection, and impaired splenic function is a feature of SCD patients, even in those who still anatomically have a spleen. This patient had a surgical splenectomy and, in addition, had probably lost some of the acquired malaria-immunity by having lived for several years in malaria-free areas. This patient is a compelling reminder that long-term anti-malarial prophylaxis should be offered to all patients with SCD who live in malaria-endemic areas.

14.
Stroke ; 51(4): 1166-1173, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32138633

RESUMO

Background and Purpose- Widespread reductions in white matter integrity are associated with cognitive dysfunction in sickle cell anemia. Silent cerebral infarction (SCI), vasculopathy (VSC), and low hemoglobin concentration (Hb) are implicated; we aimed to determine independent contributions to microstructural white matter injury and whether white matter integrity differs across arterial territories. Methods- Sixty two children with sickle cell anemia aged 6 to 19 years were prospectively studied at Muhimbili National Hospital, Tanzania. SCI± and VSC± were identified on magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) scans by 2 neuroradiologists. Tract-based spatial statistics tested for voxel-wise differences in diffusion tensor imaging metrics (ie, fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity) between SCI± and VSC± groups, with correlations between diffusion tensor imaging metrics and Hb. In tract-based spatial statistics analyses, potentially mediating factors (ie, age, sex, as well as Hb, SCI, and/or vasculopathy) were covariates. Differences in mean diffusion tensor imaging metrics across regions of interest in arterial territories were explored. Results- Compared with SCI- patients (n=45), SCI+ patients (n=17) exhibited increased radial diffusivity in multiple regions; negative relationships were observed between mean diffusivity, axial diffusivity, and Hb (P<0.005). Compared with VSC- patients (n=49), mild (n=6) or moderate (n=7) VSC+ patients exhibited reduced fractional anisotropy in widespread regions (P<0.05) including the anterior longitudinal fasciculi, corpus callosum, internal capsule, corona radiata, and corticospinal tracts. Overall, the posterior cerebral arterial territory had higher mean mean diffusivity and mean radial diffusivity than the anterior and middle cerebral arterial territories, although no patient had vasculopathy in this area. There was an interaction between territory and vasculopathy. Conclusions- SCI, vasculopathy, and Hb are independent risk factors, and thus treatment targets, for diffuse white matter injury in patients with sickle cell anemia. Exacerbation of hemodynamic stress may play a role.


Assuntos
Anemia Falciforme/diagnóstico por imagem , Anemia Falciforme/epidemiologia , Encéfalo/diagnóstico por imagem , Imagem de Tensor de Difusão/tendências , Angiografia por Ressonância Magnética/tendências , Substância Branca/diagnóstico por imagem , Adolescente , Criança , Feminino , Humanos , Masculino , Estudos Prospectivos , Tanzânia/epidemiologia , Adulto Jovem
15.
Pediatr Neurol ; 107: 64-70, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32111561

RESUMO

BACKGROUND: Cerebral infarcts and vasculopathy in neurologically asymptomatic children with sickle cell anemia (SCA) have received little attention in African settings. This study aimed to establish the prevalence of silent cerebral infarcts (SCI) and vasculopathy and determine associations with exposure to chronic hemolysis, anemia, and hypoxia. METHODS: We prospectively studied 224 children with SCA with transcranial Doppler (TCD), and magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Regressions were undertaken with contemporaneous hemoglobin, reticulocyte count, mean prior hemoglobin, oxygen content, reticulocyte count, and indirect bilirubin. RESULTS: Prevalence of SCI was 27% (61 of 224); cerebral blood flow velocity was abnormal (>200 cm/s) in three and conditional (>170<200 cm/s) in one. Vasculopathy grades 2 (stenosis) and 3 (occlusion) occurred in 16 (7%) and two (1%), respectively; none had grade 4 (moyamoya). SCI was associated with vasculopathy on MRA (odds ratio 2.68; 95% confidence intervals [95% CI] 1.32 to 5.46; P = 0.007) and mean prior indirect bilirubin (odds ratio 1.02, 95% CI 1.00 to 1.03, P = 0.024; n = 83) but not age, sex, non-normal TCD, or contemporaneous hemoglobin. Vasculopathy was associated with mean prior values for hemoglobin (odds ratio 0.33, 95% CI 0.16 to 0.69, P = 0.003; n = 87), oxygen content (odds ratio 0.43, 95% CI 0.25 to 0.74, P = 0.003), reticulocytes (odds ratio 1.20, 95% CI 1.01-1.42, P = 0.041; n = 77), and indirect bilirubin (odds ratio 1.02, 95% CI 1.01 to 1.04, P = 0.009). CONCLUSIONS: SCI and vasculopathy on MRA are common in neurologically asymptomatic children with SCA living in Africa, even when TCD is normal. Children with vasculopathy on MRA are at increased risk of SCI. Longitudinal exposure to anemia, hypoxia, and hemolysis appear to be risk factors for vasculopathy.

16.
Hematol Oncol Stem Cell Ther ; 13(2): 66-70, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32201150

RESUMO

There is an urgent need to develop a strategy for curative options for sickle cell disease (SCD) in Africa as this is a disease of public health significance. It is common [84% of 14 million children born (2010-2050) in the world are in Africa]; survival in Africa is reported to be low however with interventions, childhood survival can reach between 50% and 90%. Tanzania, a low-middle income country, has 11,000 children born every year and estimates that at least 14,700 deaths in under five years old are due to SCD. Tanzania had an existing dedicated sickle cell clinic at Muhimbili National Hospital, established in the 1980s. In 2004, Muhimbili University of Health and Allied Sciences (MUHAS) established a research programme that integrated improving health services, advocacy and training and enrolled 5,466 patients. In 2016, sickle cell services strengthened in other health facilities. As part of the strategy for healthcare, the Sickle Cell Programme worked with the Ministry of Health to develop recommendations for comprehensive care at different levels of health care. Most countries in Africa wanted to ensure that comprehensive care was available before putting in place curative therapy such as Haematopoietic Stem Cell Transplantation (HSCT). However, factors that accelerated the need to develop a strategy for curative care including progress and better outcomes in transplantation, increase in demand and investment in tertiary healthcare facilities. Tanzania is exploring transplantation services in 4 tertiary level referral hospitals and using the progress in genomic research in Africa to participate in gene therapy. Tanzania has successfully established training for health professionals with formal programmes and continuous medical education as well as staff exchange programmes with different partners including UK and USA. Advocacy involves active engagement with the SCD community with partnership with community organisations. Tanzania has demonstrated that there is progress in developing a strategy for curative therapies for SCD in Africa but has emphasized the need for these efforts to complement comprehensive care. A model that has proven to be successful in Tanzania integrates health, advocacy, research and training and can be used in establishing curative therapies in Tanzania as well as other countries in Africa.


Assuntos
Anemia Falciforme/terapia , Pré-Escolar , Humanos , Lactente , Tanzânia
19.
Blood Adv ; 3(23): 4002-4020, 2019 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-31809537

RESUMO

To address the global burden of sickle cell disease and the need for novel therapies, the American Society of Hematology partnered with the US Food and Drug Administration to engage the work of 7 panels of clinicians, investigators, and patients to develop consensus recommendations for clinical trial end points. The panels conducted their work through literature reviews, assessment of available evidence, and expert judgment focusing on end points related to patient-reported outcome, pain (non-patient-reported outcomes), the brain, end-organ considerations, biomarkers, measurement of cure, and low-resource settings. This article presents the findings and recommendations of the end-organ considerations, measurement of cure, and low-resource settings panels as well as relevant findings and recommendations from the biomarkers panel.


Assuntos
Anemia Falciforme/fisiopatologia , Cardiopatias/etiologia , Pneumopatias/etiologia , Insuficiência Renal Crônica/etiologia , Cardiopatias/patologia , Humanos , Pneumopatias/patologia , Insuficiência Renal Crônica/patologia
20.
Front Genet ; 10: 943, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31649726

RESUMO

Sickle cell disease (SCD) is one of the most prevalent genetic conditions in sub-Saharan Africa. It is a chronic, lifelong disease often characterized by severe pain. However, SCD has received little investment terms of health research, though there is currently a growing pool of SCD data from health and research facilities in different countries. To facilitate research on SCD in Africa, the SickleInAfrica consortium has established a SickleInAfrica registry. The registry will store a systematic collection of longitudinal data from persons with SCD across sub-Saharan Africa, and currently, participants are being enrolled in Ghana, Nigeria, and Tanzania. In establishing this registry, the SickleInAfrica consortium decided to actively identify and anticipate possible ethical issues that may arise in the development and management of the registry. This was motivated, in part, by the near absence of well documented ethical issues for registry research in Africa, more-so for registries enrolling participants across multiple countries and for a genetic condition. The consortium aims to establish standards for the equitable use of data stored in the registry. This paper presents a comprehensive report on the ethical considerations that came up in setting up a genetic disease registry across multiple African countries and how they were addressed by the SickleInAfrica consortium. Major issues included: active involvement of patients in the initiation and management of the registry; questions of assent and re-consent; the importance of ensuring that fears of exploitation are not replicated in African-African research collaborations; and the importance of public engagement in the management of registries. Drawing on this experience, SickleInAfrica plans to set up an ethics helpdesk for genetic disease registries and research in Africa.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...