White Paper: Pathways to Progress in Newborn Screening for Sickle Cell Disease in Sub-Saharan Africa

Sickle Cell Disease (SCD) is among the most common single-gene diseases in the world but evidence-based comprehensive health care has not been implemented where the highest prevalence of SCD occurs, in sub-Saharan Africa (SSA). It represents an urgent health burden, both in terms of mortality and morbidity with an estimated mortality of 8-16% in children under 5 years in SSA. Addressing the high mortality of SCD in SSA and for effective management of SCD, newborn screening (NBS) should be incorporated with prevention of infections (including pneumococcal septicaemia and malaria), parental education and support at all levels of healthcare provision to enable timely recognition. The NBS working group of the Africa Sickle Cell Research Network (AfroSickleNet) collaboration surveyed current projects in NBS in SSA, and current conditions that hinder more widespread implementation of NBS for SCD. Solutions based on new point-of-care testing technology to disseminate education, and implementation science approaches that leverage existing resources are proposed.

Low-dose hydroxycarbamide therapy may offer similar benefit as maximum tolerated dose for children and young adults with sickle cell disease in low-middle-income settings

The multiple clinical benefits of hydroxycarbamide in sickle cell disease are supported by a large body of evidence. The maximum tolerated dose (MTD) is the regimen recommended by guidelines from a panel of National Heart, Lung, and Blood Institute (NHLBI) experts, but other dosage regimens have been used in babies (BABY-HUG) 9 to 18 months old (20 mg/kg per day) and developing countries such as India (10 mg/kg per day); however, there has been no direct comparison of the efficacy, effectiveness, or cost-effectiveness of these different regimens. The purpose of this review was to investigate the current situation with various hydroxycarbamide regimens with particular relevance to low-middle-income countries. In regard to methodology, a literature review was undertaken by using multiple databases in PubMed and Google and the search terms included sickle cell disease, hydroxyurea, hydroxycarbamide, sickle cell anaemia, low-middle-income countries, Sub-Saharan Africa, and India. Although MTD regimens have been widely used in research, especially within North America, clinical trials elsewhere tend to use fixed-dose regimens. In a survey of haematologists across Europe and Africa, 60% (75% response rate) did not use the MTD regimen for hydroxycarbamide treatment of sickle cell disease. The recommendations are (1) for practical purposes to commence using fixed-dose hydroxycarbamide in line with BABY-HUG recommendations and then (2) to consider or propose a trial comparing MTD escalation with various fixed doses and to include as end points health-related quality of life, haemoglobin F levels, adherence, and cost-effectiveness.

Variations in the β-globin genes of sickle cell anaemia patients in Zaria, Northwestern, Nigeria

CONTEXT

Sickle Cell Anaemia (SCA) is a genetic disorder with a life-long disability, which is of public health importance. The diversity in its clinico-pathologic and laboratory presentations may be due to the interplay between additional genetic differences and environmental factors. The genetic factors may be within the β-globin gene itself, the β-globin gene cluster or elsewhere in the genome.

AIM

To characterize the β-globin gene for variations associated with the Sickle Cell mutation.

SETTINGS AND DESIGN

A cross-sectional descriptive study involving 51 adult SCA patients attending Sickle Cell Clinic of Haematology Department Ahmadu Bello University (ABUTH) Zaria, Kaduna State, Nigeria.

METHODS AND MATERIAL

The buccal swab specimens were collected and β-globin gene DNA sequencing was done. The sequences obtained were compared with a Genbank Reference β-globin gene (NC_000011.9) using Basic Local Alignment Search Tool (BLAST), and variations noted. Data generated were analyzed using SPSS Version 20.0.

STATISTICAL ANALYSIS USED

Data generated was summarized by using charts, means±2SD, and 95% confidence intervals.

RESULTS

There were 40 (78.43%) females and 11 (21.57%) males. The mean age of the participants was 25.35 ± 7.67 years, 95% CI (23.20, 27.51). The classic sickle cell mutation A T was present in all participants. The mean number of β-Globin gene variations was 8.61±11.30, 95% CI (5.43, 11.78). The number of Substitutions were 122 (27.79%), insertions 184 (41.91%), and deletions 133 (30.30%). These occurred in various combinations. The mean number of substitutions, insertions, and deletions were 2.39±3.23, 3.61±7.66, and 2.60±2.46 with 95% CIs of (1.48, 3.30), (1.45, 5.76), and (1.92, 3.30) respectively.

CONCLUSIONS

There are β-globin gene variations in SCA patients in Zaria, and locally relevant genetic database of the SCA population will be the cornerstone in understanding genotype-phenotype interactions in this disorder.

Erythropoietic Response to Anaemia of Dialysis Naïve Patients with Chronic Kidney Disease in Zaria, North-West Nigeria

Introduction

Chronic kidney disease (CKD) is a global health problem with an increasing prevalence worldwide. Anemia is one of its consistent and severe hematological complications although its mechanism is not fully elucidated. The primary defect could manifest as serum erythropoietin (sEPO) deficiency or EPO resistance. We set out to determine the erythropoietic response to anemia of patients with CKD and its relationship with their iron status in a cross-sectional descriptive study of 91 patients in various stages of CKD. Materials and Methods: Soluble transferrin receptor (sTfR), sEpo, and serum ferritin levels were determined using ELISA method (Diagnostic Automation Inc and WKEA med supplies corp.). Data generated were analyzed using Epi Info version 3.5.3 and level of statistical significance was set at ≤0.05. Results: Participants comprised of 50 females (54.9%) and 41 (45.1%) males with an overall mean age of 47 ± 15 years. The major causes of CKD were hypertension (HTN) (50.54%), diabetes mellitus (DM) (6.59%), and HTN + DM (19.78%). The mean hemoglobin (Hb) concentration of the participants was 10.97 ± 2.28 g/dl; the red cell indices were within normal ranges except for Red cell distribution width-Coefficient of variation (%) which was elevated (16.29%). The mean serum ferritin, sTfR, and sEpo were 70.58 ± 46.44 ng/ml (interquartile range [IQR] 82.00), 22.9 ± 49.7 ng/ml (IQR 15.00), and 12.49 ± 33.47 IU/L (IQR 6.00), respectively, with a high variance. Serum ferritin and sTfR are consistently low across the stages of CKD (range between 54.54 ng/ml and 88.64 ng/ml), but sEPO for stage 3 and 4 showed a 2-fold increase when compared to normal level at Hb 10.97 g/dl (29.54 IU/L and 38.83 IU/L, respectively). Correlation between sTfR and sEpo (r² = 0.96, P = 0.001), while between sEpo and serum ferritin (r² = 0.02, P = 0.185), and between Hb and stage of CKD undulating (r² = 0.41, P = 0.001).

Conclusion

In contrast to some existing literature, this study has demonstrated that EPO resistance and iron deficiency contributes to anemia in CKD and serum ferritin can be used to assess the iron level of dialysis naïve CKD patients at every stage of the disease.