DNA testing for sickle cell anemia in Africa: Implementation choices for the Democratic Republic of Congo.

peer reviewed[en] BACKGROUND: Hemoglobin-based tests form the reference diagnostic test for SCA. In limited resource countries, these tests face limitations including cost, low sensitivity due to recurrent transfusions in endemic malaria region, and interference from fetal hemoglobin in neonatal diagnostic. This study aimed at adapting DNA-based SCA tests to limited resource countries and evaluating the economic benefit. METHODS: 338 participants were recruited in the Democratic Republic of Congo, sorted in 3 cohorts based on venous blood, umbilical cord blood (UCB) and buccal swab sampling. RFLP was performed to identify mutated allele. The feasibility and technical validity of this RFLP was evaluated for specimens collected on DBS cards and on EDTA tubes. RFLP on DBS stored at room temperature was regularly repeated to assess sample conservation. Finally, the cost analysis was performed. RESULTS: DBS cards yielded identical results to extracted DNA. Repeated testing returned the same result after four years. The DBS-based test performed on UCB or on buccal swab had a sensitivity and a precision of 100%. Cost comparison indicated that our approach costs half price of the widely used isoelectrofocussing of hemoglobin. CONCLUSION: The implemented DNA-based test approach overcomes the limitations faced by hemoglobin-based tests, while being more affordable. We propose to implement the RFLP test as a first line diagnostic test after transfusion and as second tiers for newborn screening. However, users should be aware that this test is unable to differentiate HbC from HbS or identify other point mutation of gene deletion of HBB gene.Médecine Génomique en Wallonie (WALGE/ED)3. Good health and well-bein

Clinical and biological profile of Sickle Cell Anemia children in a rural area in Central Africa.

peer reviewed[en] BACKGROUND: Sickle Cell Anemia (SCA) is the most common genetic disease worldwide caused by a single mutation in the gene HBB. The disease severity is very variable and depends on many factors. We evaluated the clinical and biological profile of sickle cell anemia children in rural Central Africa. METHODS: This cross-sectional study was conducted in the Hôpital Saint Luc de Kisantu, located 120 km away from Kinshasa-DR Congo in an area of 35 km around Kisantu with a population of roughly 80 000 individuals. We included SCA patients aged 6 months to 18 years. We collected clinical and hematological data. The SCA scoring system proposed by Adegoke et al. in 2013 was applied to determine the disease severity. We searched for factors associated to the disease severity. RESULTS: This study included 136 patients, 66 males and 70 females (sex-ratio M/F 0.94). The mean severity score was 8.21 ± 5.30 (ranges 0-23). Fifty-nine (43.4%) children had mild disease, 62 (45.6%) moderate and 15 (11%) severe disease. Girls had higher levels of HbF than boys (p = 0.003). An inverse correlation was observed between fetal hemoglobin and the disease severity (p = 0.005, r -0.239, IC95% -6.139; -1.469). Some factors such age influence the occurrence of certain chronic complications such as avascular bone necrosis. CONCLUSION: In conclusion, the disease severity of SCA depends on multiple factors. In this study, fetal hemoglobin was the main modulator of the disease severity. These data may also serve as a baseline to initiate HU treatment in this setting

Value of DNA testing in the diagnosis of sickle-cell anemia in childhood in an environment with a high prevalence of other causes of anemia.

peer reviewed[en] BACKGROUND: Sickle-cell anemia (SCA) is the most common genetic disease worldwide caused by a single mutation in the gene HBB. DNA testing can help to clarify the diagnosis when Hb electrophoresis is inconclusive. We evaluated the usefulness and feasibility of DNA-based diagnosis of SCA in rural Central Africa. METHODS: This is a cross-sectional study conducted from November 2016 to end October 2017 in the Hôpital Saint Luc de Kisantu, located 120 km from Kinshasa. This hospital offers the management of SCA patients, mainly identified using the Sickling test (Emmel test) combined with clinical features. We included patients aged 6 months to 18 years locally diagnosed as SCA, and we collected clinical and hematological data. All patients were offered Hb electrophoresis and DNA testing at the Center for Human Genetics of the University of Kinshasa. RESULTS: This study included 160 patients. Hemoglobin capillary electrophoresis suggested that 136 (85%) were homozygote SS, 13 (8.1%) were heterozygote (AS), and 11 (6.9%) were homozygote normal (AA). DNA testing confirmed these electrophoresis findings, with the exception of four patients, two AS in electrophoresis were found SS due to recent transfusion, and two SS in electrophoresis were found AS because they have compound heterozygous form S/β°-thalassemia. The diagnosis of SCA was therefore wrongly ascertained with Emmel test in 15% of patients. CONCLUSION: This study reveals a high proportion of false-positive SCA diagnoses in a rural environment in Central Africa. This underlines the importance of DNA testing in conjunction with Hb electrophoresis

PERCHING syndrome: Clinical presentation in the first African patient confirmed by clinical whole genome sequencing.

peer reviewedPERCHING syndrome is a rare multisystem developmental disorder caused by autosomal recessive (AR) variants (truncating and missense) in the Kelch-like family member 7 gene (KLHL7). We report the first phenotypic and molecular description of PERCHING syndrome in a patient from Central Africa. The patient presented multiple dysmorphic features in addition to neurological, respiratory, gastroenteric, and dysautonomic disorders. Clinical Whole Genome Sequencing in the proband and his mother identified two novel heterozygous variants in the KLHL7 gene, including a maternally inherited intronic variant (NM_001031710.2:c.793 + 5G > C) classified as Variant of Uncertain Significance and a frameshift stop gain variant (NM_001031710.2:c.944delG; p.Ser315ThrfsTer23) of unknown inheritance classified as likely pathogenic. Although the diagnosis was only evoked after genomic testing, the review of published patients suggests that this disease could be clinically recognizable and maybe considered as an encephalopathy. Our report will allow expanding the phenotypic and molecular spectrum of Perching syndrome

Connaissances, attitudes et pratiques des étudiants de l’Université de Kinshasa sur le don bénévole de sang : Knowledge, attitude, practice of students about voluntary blood donation at the University of Kinshasa

Context. Despite being located on the site of the University of Kinshasa, the Blood Bank, fails paradoxically to meet the community's need for blood. Objective. To determine the prevalence of voluntary donors and to describe the knowledge, attitude and practice of students on the voluntary blood donation. Methods. A cross sectional analysis collecting interviewes of 500 students between July and November 2014.Sociodemographic, as well as data on knowledge, attitude and practice on blood donation were registered. A score based on informations about a previous blood donation,hospitalization of a transfused family member, blood donor in the family, information on blood donation and knowledge about the importance of blood donation was assessed. A multivariate logistic regression model was used to investigate the determinants of best knowledge at the p < 0.05 level.Results. Prevalence of voluntary donors in University of Kinshasa was 12%. 84% of respondents were informed about blood donation through media (44.1%) and awareness campaigns (28.8%). Altruism was the main motivation to donate blood (37.1%) while 35.1% had never thought of doingso. "The fear of harming their health," "religion" and "the fact that transfusion is paid at hospital" were the main barriers to blood donation raised by 60%, 21% and 19% of respondents, respectively. Among the voluntary blood donors, a male predominance (90.2%) was observed. Finally, male subject (adjusted OR 2.7), age > 25 years old (aOR 1.7) and status of loyal voluntary donor (aOR 4.3) were independently associated with good knowledge of Blood donation. Conclusion. At University of Kinshasa, roughly one out of eight students routinely gives blood voluntarily. A strategy to improve the knowledge of the student community about voluntary blood donation should be developed by the BloodBank to stimulate the accession of a large number of students. Contexte et objectifs. En dépit de sa localisation dans un site universitaire, la Banque de sang des Cliniques Universitaires de Kinshasa, source potentielle de donneurs bénévoles de sang constituée par les étudiants, ne parvient pas à satisfaire les besoins en sang de la communauté. L'objectif de cette étude était de déterminer la fréquence des donneurs bénévoles sur le site de l'université et décrire le niveau de connaissance, l'attitude et la pratique des étudiants sur le don bénévole de sang. Méthodes. Dans une étude transversale, 500 étudiants choisis aléatoirement fréquentant  de Kinshasa entre juillet et novembre 2014, ont été interviewés.  Les parametres d'interêt comprenaient les caractéristiques sociodémographiques, les données sur la connaisance, l'attitude et la pratique sur le don de sang. La connaissance du don de sang a été évaluée grâce à un score qui comprenait le don du sang dans le passé, l'hospitlisation d'un membre de famille transfusé, le donneur du sang dans la famille, l'information sur le don de sang et la connaissance sur l'importance du don de sang. de sang. Un modèle de régression logistique multivariée a permis de rechercher les déterminants de la meilleure connaissance au seuil de p < 0,05. Résultats. La prévalence de donneurs bénévoles estudiantins a été de 12.2%. 84% d'enquêtês affirment avoir été informés sur le don de sang en majorité par les média (44,1%) et les campagnes de sensibilisation (28,8%). L'altruisme êtait la principale motivation á faire un don de sang (37,1%). « La peur de nuire à leur santé », « la religion » et «le fait que la transfusion soit payante en milieu en milieu hospitalier » constituaient les principaux obstacles au don de sang évoqués respectivement par 32%%, 22% et 34% des enquêtés. Parmi les donneurs bénévoles de sang, une forte prédominance masculine (90,2%) était constatée. La bonne connaissance sur le don de sang était retrouvée chez 33,4%. Les déterminants de cette bonne connaissance de don de sang êtaient le sexe masculin, l'âge>25 ans et le  statut de donneur bénévole fidélisé multipliant la chance respectivement par 2,7 ; 1,7 et 4,3. Conclusion. Pres d'un étudiant sur huit donnes régulièrement et volontairement le sang. Une stratégie visant à améliorer les connaissances de la communauté estudiantine sur le don bénévole de sang doit être développée par la Banque du sang, afin de stimuler l'adhésion d'un grand nombre d'êtudiants

Molecular genetic characterization of Congolese patients with oculocutaneous albinism.

peer reviewed[en] BACKGROUND: Oculocutaneous albinism (OCA) is an autosomal recessive genetic disorder associated with reduced or absent pigmentation in the skin, hair and eyes. OCA type 2 (OCA2) is the most common type in Sub-Saharan Africa, related to a recurrent 2.7 kb intragenic deletion. Genomic data from Congolese patients are lacking. We aimed to describe genetic causes of OCA2 in a cohort of Congolese persons with OCA, and explore possible genotype-phenotype correlations. METHODS: A cross sectional study was conducted from January 2015 to December 2017 in Kinshasa, Democratic Republic of Congo (DRC). 165 Congolese unrelated families with non-syndromic OCA, identified through patients' associations, consented to participate to this study. All index cases were tested for the known 2.7 kb deletion involving the exon 7 of the OCA2 gene. Patients heterozygous for the deletion underwent Sanger sequencing of all exons and flanking sequences in the OCA2 gene. Family segregation was performed for candidate pathogenic variants. RESULTS: The 2.7 kb deletion in the OCA2 gene was identified in 136/165 (82.4%) index cases, including 113 (68.5%) homozygotes and 23 (13.9%) heterozygotes. Sanger sequencing identified a pathogenic or likely pathogenic variant in the OCA2 gene in 12 out of 23 heterozygotes investigated (52.1%). Segregation analysis allowed us to locate the point mutation on the trans allele in the three patients from whom parental DNA was available. CONCLUSION: The OCA2 2.7 kb deletion is the major cause of non-syndromic OCA in Congolese patients recruited in this study, confirming results from other Sub-Saharan African populations. Several additional mutations were detected in OCA patient's heterozygote for the deletion, with to date no evidence for a second frequent founder mutation. The confirmation of a single mutation as the major cause will facilitate genetic counselling in this country

Clinical and laboratory characterization of adult sickle cell anemia patients in Kinshasa.

BackgroundSickle cell anemia (SCA) is a monogenic hemoglobinopathy associated with severe acute and chronic complications, with the highest incidence worldwide in Sub-Saharan Africa. The wide variability in clinical manifestations suggest that a uniform response to hydroxurea may not be attained. In view of a potential treatment with hydroxyurea (HU), we assessed the variability of clinical and hematological manifestations in a cohort of adults with SCA in Kinshasa, capital of the DR Congo in Central Africa.MethodsA cross-sectional study was conducted in a hospital dedicated to SCA management in Kinshasa. Clinical history of patients was recorded, a complete physical examination performed. The diagnosis was confirmed by means of DNA analysis. A full blood count and hemolysis markers were measured. The severity of the disease was evaluated by means of a previously reported score.ResultsThe study group consisted of 166 genetically confirmed SCA patients. The SCA severity was mild in 28.9%, moderate in 64.5% and severe in 6.6%. The disease severity score increased with patient's age (p ≤ 0.001). The severity was higher in males compared to females (p = 0.012). In males, the severity score was correlated with the presence of priapism (p = 0.045), a manifestation not previously incorporated in the severity score. The severity score was inversely correlated with the fetal hemoglobin (HbF) rate (p = 0.005). Malnutrition (BMI ConclusionIn this selected, hospital-based populations of adults with SCA, severe disease was rare, which may be due to survival bias. However, two thirds had moderate severity of the disease, mostly with a low HbF, and they may benefit from HU treatment. In the Central-African setting the separation between vaso-occlusive and hyperhemolytic sub-phenotypes was not applicable

Hydroxyurea treatment for adult sickle cell anemia patients in Kinshasa

Abstract Background: Despite a high incidence of sickle cell anemia, hydroxyurea (HU) treatment is rarely used in the DR Congo. This study aims to assess the efficacy of HU, the incidence of side effects that may limit its use in adults and to determine the dose needed for clinical improvement in patients. Methods: In a prospective study, patients received an initial dose of 15 mg/kg/day which was increased by 5 mg/kg every 6 months, up to a maximum of 30 mg/kg/day. The response and side effects to HU were evaluated biologically and clinically every 3 months during a 2‐year period. Results: Seventy adult patients with a moderate or severe clinical phenotype initiated treatment. Only minor side effects were reported. At the end of the 2‐year treatment phase, 45 (64.3%) had dropped out, of whom 33 were without a clear reason. Clinical and biological improvement was more marked during the first year. There was a reduction in severe vaso‐occlusive crises (p < 0.001), need for transfusion (p < 0.001), and hospitalization days (p = 0.038). Fetal hemoglobin (HbF) levels increased on average 2.9 times after 12 months (p < 0.001). The increase in mean corpuscular volume was greater in the first year (p < 0.001) than in the second year (p = 0.041). The decrease in leukocytes (p < 0.001) was significant during the first year. In 70% of patients, the 20 mg/kg/day dose was needed to reach the 20% HbF threshold. Conclusion: HU is effective and well tolerated. The magnitude of the response varies from one patient to another. Improvement of clinical manifestations is achieved in most patients with a relatively low dose. Effective implementation of HU treatment will require improved adherence to treatment