Biomarkers of sickle cell nephropathy in Senegal.

Sickle cell anemia (SCA) is caused by a single point variation in the ß-globin gene (HBB): c.20A> T (p.Glu7Val), in homozygous state. SCA is characterized by sickling of red blood cells in small blood vessels which leads to a range of multiorgan complications, including kidney dysfunction. This case-control study aims at identifying sickle cell nephropathy biomarkers in a group of patients living with SCA from Senegal. A total of 163 patients living with SCA and 177 ethnic matched controls were investigated. Biological phenotyping included evaluation of glycemia, glucosuria, albuminuria, proteinuria, tubular proteinuria, serum creatinine, urine creatinine, urine specific gravity and glomerular filtration rate. Descriptive statistics of biomarkers were performed using the χ2 -test, with the significance level set at p<0.05. Patients living with SCA had a median age of 20 years (range 4 to 57) with a female sex frequency of 53.21%. The median age of the control participants was 29 years (range: 4-77) with a female sex frequency of 66.09%. The following proportions of abnormal biological indices were observed in SCA patients versus (vs.) controls, as follows: hyposthenuria: 35.3%vs.5.2% (p<0.001); glomerular hyperfiltration: 47.66%vs.19.75% (p<0.001), renal insufficiency: 5.47%vs.3.82% (p = 0.182); microalbuminuria: 42.38%vs.5.78% (p<0.001); proteinuria: 39.33%vs.4.62% (p<0.001); tubular proteinuria: 40.97%vs.4.73% (p<0.001) and microglucosuria: 22.5%vs.5.1% (p<0.001). This study shows a relatively high proportion of SCA nephropathy among patients living with SCA in Senegal. Microglucosuria, proteinuria, tubular proteinuria, microalbuminuria, hyposthenuria and glomerular hyperfiltration are the most prevalent biomarkers of nephropathy in this group of Senegalese patients with SCA.

Estimating the risk of child mortality attributable to sickle cell anaemia in sub-Saharan Africa: a retrospective, multicentre, case-control study.

BACKGROUND: Many children with sickle cell disease living in sub-Saharan Africa die before reaching age 5 years. We estimate the child mortality associated with sickle cell anaemia using an indirect approach to overcome the absence of systematic screening at birth. METHODS: We did a retrospective, multicentre, case-control study in five countries in sub-Saharan Africa (Burkina Faso, Democratic Republic of the Congo, Côte d'Ivoire, Mali, and Senegal). Women with at least one child with a confirmed SS haemoglobin phenotype (sickle cell anaemia) and who had at least three (alive or deceased) children from the same father born more than 5 years ago were recruited at an outpatient consultation in a sickle cell disease care centre. Women who had children without sickle cell disease (control group) were recruited from the same area, with inclusion criteria of being a neighbour or relative of one of the mothers included in the study who had a child with sickle cell anaemia, having no child or other first-degree relative with major sickle cell syndrome, having at least three children (alive or deceased) born more than 5 years ago, and having a confirmed haemoglobin AA phenotype. During the mothers' interview, we collected data concerning the mortality of siblings from the same father of a child with sickle cell anaemia and characteristics of the family, such as age at the time of the survey and the level of education of both parents. Mortality rates were calculated for children younger than 1, 5, and 10 years using the Kaplan-Meier method after excluding the index children. We assumed, as per Mendel law, that in families who have a child with sickle cell anaemia and healthy heterozygous parents, 25% of children born on average have sickle cell anaemia. A multivariate Cox model was used to describe socioeconomic and geographical factors associated with mortality. FINDINGS: Between Sept 1, 2017, and Nov 30, 2020, 1563 women who had at least one child with sickle cell anaemia and 4972 women from the same neighbourhood who had children without sickle cell disease were assessed for eligibility. Of 1563 women, 248 were excluded because the genotype of the index child was SC or S ß-thalassaemia. 1315 families with cases of sickle cell anaemia and 1243 control families were included in the study. The median age of children (alive) was 14 years (IQR 8-20) in control families and 13 years (8-19) in families with cases of sickle cell anaemia. 5532 [50·6%] of 10 924 children were male. Mortality rates were 15·3% (95% CI 13·3-17·3) for children with sickle cell anaemia younger than 1 year, 36·4% (33·4-39·4) for those younger than 5 years, and 43·3% (39·3-47·3) for those younger than 10 years. Multivariate Cox survival analysis showed that belonging to a family with sickle cell anaemia (hazard ratio [HR] 2·23, 95% CI 1·96-2·54), living in the Democratic Republic of the Congo (HR 1·64, 1·34-2·01), having an older parent (father or mother age had similar effect; HR 1·12, 1·05-1·19 per 10 years of age), or a significantly higher global Multidimensional Poverty Index (HR 1·09, 1·03-1·14), independently increased the risk of mortality. Whereas, living in Senegal (HR 0·70, 95% CI 0·57-0·86) or having a mother with higher education (high school HR 0·66, 0·55-0·80 or advanced HR 0·41, 0·28-0·61) independently decreased the risk of mortality. INTERPRETATION: Although higher than in high-income countries and affected by non-specific socioeconomic factors, the estimated mortality in children with sickle cell anaemia living in sub-Saharan African cities was substantially lower than previous estimates, suggesting an improvement of sickle cell anaemia care in this setting. FUNDING: Fondation Pierre Fabre. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Polymorphisms in Inflammatory Genes Modulate Clinical Complications in Patients With Sickle Cell Disease.

Sickle cell disease (SCD), the most common monogenic disease worldwide, is marked by a phenotypic variability that is, to date, only partially understood. Because inflammation plays a major role in SCD pathophysiology, we hypothesized that single nucleotide polymorphisms (SNP) in genes encoding functionally important inflammatory proteins might modulate the occurrence of SCD complications. We assessed the association between 20 SNPs in genes encoding Toll-like receptors (TLR), NK cell receptors (NKG), histocompatibility leukocyte antigens (HLA), major histocompatibility complex class I polypeptide-related sequence A (MICA) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), and the occurrence of six SCD clinical complications (stroke, acute chest syndrome (ACS), leg ulcers, cholelithiasis, osteonecrosis, or retinopathy). This study was performed in a cohort of 500 patients. We found that the TLR2 rs4696480 TA, TLR2 rs3804099 CC, and HLA-G, rs9380142 AA genotypes were more frequent in patients who had fewer complications. Also, in logistic regression, the HLA-G rs9380142 G allele increased the risk of cholelithiasis (AG vs. AA, OR 1.57, 95%CI 1.16-2.15; GG vs. AA, OR 2.47, 95%CI 1.34-4.64; P = 0.02). For SNPs located in the NKG2D loci, in logistic regression, the A allele in three SNPs was associated with a lower frequency of retinopathy, namely, rs2246809 (AA vs. GG: OR 0.22, 95%CI 0.09-0.50; AG vs. GG: OR 0.47, 95%CI 0.31-0.71; P = 0.004, for patients of same origin), rs2617160 (AT vs. TT: OR 0.67, 95%CI 0.48-0.92; AA vs. TT: OR 0.45, 95%CI 0.23-0.84; P = 0.04), and rs2617169 (AA vs. TT: OR 0.33, 95%CI 0.13-0.82; AT vs. TT: OR 0.58, 95%CI 0.36-0.91, P = 0.049, in patients of same SCD genotype). These results, by uncovering susceptibility to, or protection against SCD complications, might contribute to a better understanding of the inflammatory pathways involved in SCD manifestations and to pave the way for the discovery of biomarkers that predict disease severity, which would improve SCD management.

Combined and differential effects of alpha-thalassemia and HbF-quantitative trait loci in Senegalese hydroxyurea-free children with sickle cell anemia.

BACKGROUND: Our objective was to investigate the combined and differential effects of alpha-thalassemia -3.7 kb deletion and HbF-promoting quantitative trait loci (HbF-QTL) in Senegalese hydroxyurea (HU)-free children and young adults with sickle cell anemia (SCA). PROCEDURE: Steady-state biological parameters and vaso-occlusive crises (VOC) requiring emergency admission were recorded over a 2-year period in 301 children with SCA. The age of the first hospitalized VOC was also recorded. These data were correlated with the alpha-globin and HbF-QTL genotypes. For the latter, three different genetic loci were studied (XmnI, rs7482144; BCL11A, rs1427407; and the HBS1L-MYB region, rs28384513) and a composite score was calculated, ranging from zero (none of these three polymorphisms) to six (all three polymorphisms at the homozygous state). RESULTS: A positive clinical impact of the HbF-QTL score on VOC rate, HbF, leucocytes, and C-reactive protein levels was observed only for patients without alpha-thalassemia deletion. Conversely, combination of homozygous -3.7 kb deletion with three to six HbF-QTL was associated with a higher VOC rate. The age of the first hospitalized VOC was delayed for patients with one or two alpha-thalassemia deletions and at least two HbF-QTL. CONCLUSION: Alpha-thalassemia -3.7 kb deletion and HbF-QTL are modulating factors of SCA clinical severity that interact with each other. They should be studied and interpreted together and not separately, at least in HU-free children.

Prevalence and correlates of growth failure in young African patients with sickle cell disease.

Growth failure (GF) in children with sickle cell disease (SCD) tends to decline in high-income countries, but data are lacking in sub-Saharan Africa. We performed a cross-sectional study nested in the CADRE (Cœur, Artères et DREpanocytose) cohort in Mali, Senegal, Cameroon, Gabon and the Ivory Coast. SCD patients and healthy controls aged 5-21 years old were recruited (n = 2583). Frequency of GF, defined as a height, weight or body mass index below the 5th percentile on World health Organization growth charts, was calculated. We assessed associations between GF and SCD phenotypic group, clinical and biological characteristics and history of SCD-related complications. GF was diagnosed in 51% of HbSS, 58% of HbSß0 , 44% of HbSC, 38% of HbSß+ patients and 32% of controls. GF in patients was positively associated with parents' lower education level, male sex, age 12-14 years, lower blood pressure, HbSS or HbSß0 phenotypes, icterus, lower haemoglobin level, higher leucocyte count and microalbuminuria. No association was found between GF and clinical SCD-related complications. In sub-Saharan Africa, GF is still frequent in children with SCD, especially in males and during adolescence. GF is associated with haemolysis and microalbuminuria, but not with the history of SCD-related clinical complications.

[Adrenocorticotropic hormone (ACTH) insensitivity syndrome: about a case]. / Syndrome de résistance à l'Adrénocorticotrophine Hormone (ACTH): à propos d'un cas.

Adrenocorticotropic hormone (ACTH) insensitivity syndrome is one of the rare causes of adrenal insufficiency in children. All described inherited ACTH insensitivity forms are of autosomal recessive origin. In our resource-poor Countries, many of these rare diseases are ignored or not diagnosed due to inadequate technical equipments. We report the case of a 4-month old infant hospitalized for refractory hypoglycaemias. Despite the patient had generalized and severe melanodermia, digestive disorders and ion channel disorders the diagnosis of cortisol deficiency was only diagnosed retrospectively during respiratory arrest with favorable outcome under hydrocortisone therapy. This study aims to highlight the clinical, laboratory and therapeutic features of peripheral cortisol deficiency, without enzymatic blocks, including this adrenocorticotropic hormone (ACTH) insensitivity syndrome.

Vaccination coverage and immunization timeliness among children aged 12-23 months in Senegal: a Kaplan-Meier and Cox regression analysis approach.

INTRODUCTION: Expanded programme on immunizations in resource-limited settings currently measure vaccination coverage defined as the proportion of children aged 12-23 months that have completed their vaccination. However, this indicator does not address the important question of when the scheduled vaccines were administered. We assessed the determinants of timely immunization to help the national EPI program manage vaccine-preventable diseases and impact positively on child survival in Senegal. METHODS: Vaccination data were obtained from the Demographic and Health Survey (DHS) carried out across the 14 regions in the country. Children were aged between 12-23 months. The assessment of vaccination coverage was done with the health card and/or by the mother's recall of the vaccination act. For each vaccine, an assessment of delay in age-appropriate vaccination was done following WHO recommendations. Additionally, Kaplan-Meier survival function was used to estimate the proportion vaccinated by age and cox-proportional hazards models were used to examine risk factors for delays. RESULTS: A total of 2444 living children between 12-23 months of age were included in the analysis. The country vaccination was below the WHO recommended coverage level and, there was a gap in timeliness of children immunization. While BCG vaccine uptake was over 95%, coverage decreased with increasing number of Pentavalent vaccine doses (Penta 1: 95.6%, Penta 2: 93.5%: Penta 3: 89.2%). Median delay for BCG was 1.7 weeks. For polio at birth, the median delay was 5 days; all other vaccine doses had median delays of 2-4 weeks. For Penta 1 and Penta 3, 23.5% and 15.7% were given late respectively. A quarter of measles vaccines were not administered or were scheduled after the recommended age. Vaccinations that were not administered within the recommended age ranges were associated with mothers' poor education level, multiple siblings, low socio-economic status and living in rural areas. CONCLUSION: A significant delay in receipt of infant vaccines is found in Senegal while vaccine coverage is suboptimal. The national expanded program on immunization should consider measuring age at immunization or using seroepidemiological data to better monitor its impact.

[Hemolytic-uremic syndrome (HUS) in children at the University Hospital Center in Dakar: about four cases]. / Syndrome hémolytique et urémique de l'enfant au Centre Hospitalier Universitaire (CHU) de Dakar: à propos de quatre observations.

Hemolytic-uremic syndrome (HUS) is a common cause of organic acute renal failure (ARF) in children. It is a progressive complication of acute gastroenteritis (AGE), especially caused by Escherichia coli in children. This study aimed to describe the clinical, therapeutic and evolutionary aspects of this affection in four children. We collected four cases of HUS. The average age was 10,5 months (5-15mois), exclusively boys. Clinical examination revealed a hemolytic anemia (pallor and jaundice), oligoanuria and edematous syndrome (2 cases), arterial hypertension (1 patient), AGE associated with severe dehydration and hypovolemic shock (2 patients), consciousness disorders. ARF was found in all patients as well as thrombocytopenia and schizocytes smear. Direct Coombs test was negative. Hyperkalemia was found in 3 patients, of whom 1 with hyperkalemia level of more than 9.2 mmol/L, hyponatremia at 129 mmol/l (1 patient) and hypernatremia at 153 mmol/l (1 patient). HUS was secondary to pneumococcal pneumonia (1 patient) while AGE was secondary to E. coli (1 patient). The treatment was mainly symptomatic and included fluid restriction, transfusion of red cell concentrates, diuretics, peritoneal dialysis and hemodialysis. The evolution was marked by the onset of chronic renal failure (1 patient) after 6 months of follow-up and by recovery (1 case). Three patients died. HUS is the most common cause of organic acute renal failure in newborns. Diagnosis is essentially biological, treatment is mostly symptomatic.

[Congenital hypothyroidism in Dakar: about 28 cases]. / Hypothyroïdie congénitale à Dakar: à propos de 28 cas.

Child hypothyroidism has been little studied in Senegal. The aim of this study was to evaluate the epidemiological, diagnostic and evolutionary aspects of congenital hypothyroidism. We conducted a descriptive-analytical retrospective study of all children treated for congenital hypothyroidism at the Albert-Royer National Children's Hospital Center over the period from 2001 to 2014 (14 years). We collected and analyzed socio-demographic, clinical and evolutionary data from patient medical records. A total of 28 patients were included in the study, an average of 2 cases per year. The average age of discovery of hypothyroidism was 54.25 ± 43 months with a female predominance (Sex-ratio 0.47). Only 2 cases of hypothyroidism were diagnosed in the neonatal period. Consanguinity was present in 68% of patients. Clinical signs were dominated by the delay in psychomotor acquisitions (96%), hypothermia (46%), cranio-facial dysmorphia (43%) and goiter (39%). Growth retardation was constant beyond 6 months. The etiologies were dominated by hormonosynthesis disorders (84.21%). During the study period, mean SD of patients had decreased from -3.5 SD to -2.25 SD for a median treatment duration of 28 months. Mental retardation was present in 73% of cases. Growth retardation and mental retardation were more severe as the diagnosis was late. Our results confirm the inadequacy of early management of patients. It is urgent to implement a routine neonatal screening system in order to improve the mental prognosis of this condition.