Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

Determination of birth prevalence of sickle cell disease using point of care test HemotypeSC™ at Rundu Hospital, Namibia

BACKGROUND

Sickle cell disease (SCD), a noncommunicable disease, has the greatest burden in sub-Saharan Africa. The majority of children (50-90%) with SCD die before their 5th birthday, with approximately 150,000-300,000 annual SCD child deaths in Africa. In developed countries, newborn screening (NBS) has been shown to improve the survival of children with sickle cell disease, with under5 childhood mortality reduced tenfold due to interventions performed before the development of complications. Point -of-care tests have been developed for resource limited settings to expand NBS. The aim of this study was to determine the birth prevalence of sickle cell disease in Namibia using the HemoTypeSC™ point-of-care test.

METHODS

A cross-sectional descriptive study was carried out at Rundu Intermediate Hospital in the Kavango East Region. Two hundred and two (202) well newborns within 72 h of birth were recruited for the study from 22 February to the 23th March 2023. Descriptive statistics were used to compute the haemoglobin types of the study participants.

RESULTS

The majority of the participants (n = 105, 52%) were females, and (n = 97,48%) were males. The median age of the participants was 23 h (Q1, Q3; 11; 33),) with an age range of 2-98 h. Sickle cell trait was present in 9.4% of the screened newborns, no homozygous disease was detected, and 90.6% had Hb AA.

CONCLUSIONS

This study is the first to measure HbS gene carriage at birth using HemotypeSC point-of-care testing in Namibia. There was a moderate prevalence of sickle cell traits but no SCD. This baseline study may provide the foundation for larger epidemiological surveys to map HbS gene carriage in Namibia to provide evidence for policy makers to fashion appropriate SCD newborn screening services.

Newborn screening for sickle cell disease in Kisangani, Democratic Republic of the Congo: an update

BACKGROUND

Neonatal screening is the first action necessary to identify children with sickle cell disease (SCD) and thus ensure their care. Using rapid tests to give an immediate result to families is a new resilient approach of great interest. These two aspects are essential for establishing an adequate health policy for this disease. This study was undertaken in Kisangani to update the current incidence of neonatal SCD.

METHODS

Heel prick blood samples of 1432 babies born from different racial groups of parents living in Kisangani were collected at birth and screened using a point of care test, i.e. the HemoTypeSC^TM.

RESULTS

The incidence at birth was 2.2% (n = 31; 95% CI: [1.5%-3.1%]) for HbSS homozygosity and 21% (n = 303; 95% CI: [19%-23%]) for HbAS heterozygosity. Compared to a previous study in 2010; the incidence at the birth of the HbSS form has doubled, while that of the heterozygous form HbAS remained almost unchanged. The inter-ethnic incidence of HbSS among the five top-represented ethnic groups was significant (<0.001).

CONCLUSION

The prevalence of homozygote form has doubled compared to the 0.96% reported in 2010. Setting up a neonatal screening program and an awareness unit is necessary to assess the need for care services correctly.

Neonatal Screening for Sickle Cell Disease in Congo

Introduction

Sickle cell disease is an autosomal recessive inherited disorder due to the mutation of a gene coding for the globin beta chain. The aim of this study is to update the epidemiological data on hemoglobinoses, in particular sickle cell disease in newborns in Congo.

Materials and Methods

This was a descriptive cross-sectional study, conducted from October 1, 2019, to March 31, 2020, throughout the Congolese national territory. It involved all full-term newborns, without distinction of nationality, aged 5 days or less, and whose parents consented to participate in the study. The blood samples, taken at the heel and collected on Whatman blotting paper, were analyzed using the HPLC Variant NBS machine.

Results

In 2897 newborns (NN) screened, hemoglobin abnormalities were found in 603 NN (20.81%). The mean age of these newborns was 1 day (extremes 0 and 5 days). The male-to-female ratio was 1.03. Abnormal hemoglobins were mainly Hb S (n = 597 (97.71%)); Hb C (n = 5 (0.82%)); and variants (n = 7 (1.15%)). The national prevalence of major sickle cell (MSC) syndromes and sickle cell trait was 1.35% and 19.43%, respectively. The prevalence ranged from 1.77% to 2.56% for MSS in four departments and from 20.5% to 25.8% for the sickle cell trait in six other departments.

Conclusion

Data on homozygous sickle cell disease remain consistent with previous studies. However, further studies should clarify the molecular anomalies of the variants observed in our samples.

Prevalence of pyruvate kinase deficiency: A systematic literature review

OBJECTIVES

Pyruvate kinase deficiency (PK deficiency) is a rare disorder caused by compound heterozygosity or homozygosity for > 300 mutations in the PKLR gene. To understand PK deficiency prevalence, we conducted a systematic literature review.

METHODS

We queried Embase and Medline for peer-reviewed references reporting PK deficiency prevalence/incidence, PKLR mutant allele frequency (MAF) among the general population, or crude results from which these metrics could be derived.

RESULTS

Of 1390 references screened, 1296 were excluded after title/abstract review; 60 were excluded after full-text review. Four of the remaining 34 studies were considered high-quality for estimating PK deficiency prevalence. Two high-quality studies identified cases from source populations of known sizes, producing estimates of diagnosed PK deficiency prevalence of 3.2 and 8.5 per million. Another high-quality study derived an estimate of diagnosed PK deficiency prevalence of 6.5 per million by screening jaundiced newborns. The final high-quality study estimated total diagnosed and undiagnosed PK deficiency prevalence to be 51 per million through extrapolation from observed MAFs.

CONCLUSIONS

We conclude that prevalence of clinically diagnosed PK deficiency is likely between 3.2 and 8.5 per million in Western populations, while the prevalence of diagnosed and undiagnosed PK deficiency could possibly be as high as 51 per million.

Assessment of Hemoglobin Variants in Patients Receiving Health Care at the Ho Teaching Hospital: A Three-Year Retrospective Study

Background

It is estimated that one out of every three Ghanaians has hemoglobin genotype mutation. This change in genetic make-up may result in genotypes such as HbAS, HbSS, and HbSC. Many children in low- and middle-income countries die even before they are diagnosed with sickle cell disease (SCD). In Africa, there are limited data on the incidence and prevalence of SCD and the Volta region of Ghana is no exception.

Aim

The aim of this study was to determine the prevalence of SCD and to assess the hemoglobin variants among patients attending Ho Teaching Hospital.

Methods

A retrospective study design was used to extract information from the Hospital Administration and Management Systems (HAMS) on the hemoglobin electrophoresis results and corresponding full blood count results of the SCD and sickle cell anemia (SCA) patients as well as patients who were asked to do Hb electrophoresis irrespective of their sickling status. Data were collected for the period January 2016 to December 2018. Sickle cell disease status was determined using the Hb genotypes from the Hb electrophoresis results. The full blood count was used to categorize the severity of anemia based on the hemoglobin concentration in the SCA and SCD patients.

Results

A total of 1,523 subjects were included in the study of which the prevalence for sickle cell disease was 16.7%. The SCD genotypes included HbS (6.2%), HbSC (7.9%), and HbSF (2.6%). Hemoglobin C disease (HbCC) constituted 0.3% out of the total prevalence of SCD. The prevalence of anemia was 99.2%, with the severest form in HbS. Also, majority of the SCD patients had severe anemia. Difference in the severity of anemia was found to be significant among both male (P=0.006) and female (P=0.004) participants with SCD.

Conclusion

Patients receiving health care at the Ho Teaching Hospital had different hemoglobin variants with HbAS recording the highest prevalence. The high incidence of hemoglobin AS implies the possibility of having an increased population of individuals with sickle cell disease in future if measures are not put in place to improve screening, counseling, and education of the public about the health threat SCD poses.

Universal newborn screening: A roadmap for action

Newborn screening (NBS) prevents morbidity and mortality by screening babies for selected disorders in the first days of life so that early diagnosis and treatment can be initiated. Congenital disorders impact an estimated 8 million or 6% of annual births worldwide, and of the top five that contribute 25% to the global burden of these disorders, three can be identified and managed by NBS. There are determined pockets of activity in Latin America, Sub-Saharan Africa, and the Asia Pacific region, where partnerships among government, non-governmental organizations, academia, the private sector and civil society are developing novel NBS programs that are both saving lives and preventing disability in those who survive.

Prevalence of Iron Deficiency and Iron Deficiency Anemia in the Northern and Southern Provinces of Rwanda

Background

Anemia remains a public health problem in Rwanda, affecting 38% of young children and 17% of reproductive-aged women (Demographic and Health Survey [DHS] 2010). The importance of iron deficiency (ID) as a cause of anemia in Rwanda is not known.

Objective

We aimed to estimate the prevalence of ID and iron deficiency anemia (IDA) among young children and women in 2 provinces of Rwanda.

Methods

We conducted a cluster randomized survey, selecting 408 rural households each in the Northern and Southern Provinces of Rwanda in 2010. Anemia was defined as hemoglobin <110 g/L in children and <120 g/L in nonpregnant women after correction for altitude. We defined ID as (1) serum transferrin receptor (TfR) >8.3 mg/L or (2) serum ferritin (SF) <12 µg/L in children and <15 µg/L in nonpregnant women after correction for inflammation.

Results

The prevalence of anemia was 30.9% (95% confidence interval [CI], 26.4-35.8) in children (n = 577) and 11.2% (95% CI, 8.4-14.7) in women (n = 595). The prevalence of ID in children was 3.1% (95% CI, 1.8-5.1) as defined by high TfR and 5.9% (95% CI, 4.0-8.4) as defined by low SF. Similarly, 3.0% (95% CI, 1.8-4.8) of women had high TfR and 4.8% (95% CI, 3.2-7.2) had low SF. The prevalence of IDA (low SF with concurrent anemia) ranged from 1.4% (95% CI, 0.5-3.6) among women in the North to 5.6% (95% CI, 3.1-10.0) among children in the South.

Conclusions

ID is likely not an important contributor to anemia in the Northern and Southern Provinces of Rwanda. This finding warrants further investigation into other causes of anemia.

Hemoglobin variants identified in the Uganda Sickle Surveillance Study

The Uganda Sickle Surveillance Study analyzed dried blood spots that were collected from almost 100 000 infants and young children from all 10 regions and 112 districts in the Republic of Uganda, with the primary objective of determining the prevalence of sickle cell trait and disease. An overall prevalence of 13.3% sickle cell trait and 0.7% sickle cell disease was recently reported. The isoelectric focusing electrophoresis technique coincidentally revealed numerous hemoglobin (Hb) variants (defined as an electrophoresis band that was not Hb A, Hb F, Hb S, or Hb C) with an overall country-wide prevalence of 0.5%, but with considerable geographic variability, being highest in the northwest regions and districts. To elucidate these Hb variants, the original isoelectric focusing (IEF) gels were reviewed to identify and locate the variant samples; corresponding dried blood spots were retrieved for further testing. Subsequent DNA-based investigation of 5 predominant isoelectric focusing patterns identified 2 α-globin variants (Hb Stanleyville II, Asn78Lys; Hb G-Pest, Asp74Asn), 1 β-globin variant (Hb O-Arab, Glu121Lys), and 2 fusion globin variants (Hb P-Nilotic, β31-δ50; Hb Kenya, ^Aγ81Leu-β86Ala). Compound heterozygotes containing an Hb variant plus Hb S were also identified, including both Hb S/O-Arab and HbS/Kenya. Regional differences in the types and prevalence of these hemoglobin variants likely reflect tribal ancestries and migration patterns. Algorithms are proposed to characterize these Hb variants, which will be helpful for emerging neonatal hemoglobinopathy screening programs that are under way in sub-Saharan Africa.

Feasibility of a newborn screening and follow-up programme for sickle cell disease among South Gujarat (India) tribal populations

OBJECTIVES

To evaluate the feasibility of a newborn screening and follow-up programme for sickle cell disease (SCD) among tribal populations of south Gujarat, India.

METHODS

A total of 5467 newborn babies were screened over 2 years using High-performance liquid chromatography, with diagnosis by molecular analysis. The SCD babies were followed-up clinically and haematologically regularly for 1.5 to 5 years to describe the course of the disease.

RESULTS

Thirty-three babies (0.60%) were sickle homozygous, 13 (0.23%) were-sickle-β-thalassaemia, 687 (12.5%) were sickle heterozygous, and 4736 were unaffected. The parents of SCD babies were educated and counselled for home care. There were 32 babies (69.5%) who could be clinically and haematologically followed-up; 7 babies (21.8%) presented with severe clinical complications, whereas 18 (56.2%) babies were asymptomatic till the last follow-up. The variation in clinical presentation was seen in spite of the presence of ameliorating factors, such as high fetal haemoglobin, Xmn-I polymorphism, and α-thalassaemia.

CONCLUSION

In addition to demonstrating the possibility of establishing a newborn screening programme for sickle cell disorders among tribal populations, this study has shown that the disease is not always mild among tribal groups in India, as previously believed. There is a need, therefore, for increasing awareness among these tribal groups about the disease, and for regular monitoring of affected babies to reduce morbidity and mortality and to understand the natural course of the disease.

Glucose-6-phosphate dehydrogenase deficiency among children attending the Emergency Paediatric Unit of Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human enzyme deficiencies in the world. It is particularly common in populations living in malaria-endemic areas, affecting more than 400 million people worldwide. This present study was conducted with the aim of determining the prevalence of G6PD deficiency among children visiting the Emergency Paediatric Unit of Usmanu Danfodiyo University Teaching Hospital for pediatric-related care. The study included 118 children, made up of 77 (65.3%) males and 41 (34.7%) females aged ≤5 years with mean age of 3.26 ± 1.90 years. Randox G6PD quantitative in vitro test screening was used for the diagnosis of G6PD deficiency. Of the 118 children tested, 17 (14.4%) were G6PD-deficient. Prevalence of G6PD deficiency was concentrated predominantly among male children (22.1%). Male sex was significantly correlated with G6PD deficiency among the children studied (r = 7.85, P = 0.01). The highest prevalence occurred among children in the 2- to 5-year age-group. Of the 17 G6PD-deficient children, twelve (70.2%) were moderately deficient, while five (29.4%) were severely deficient. Blood film from G6PD-deficient children indicated the following morphological changes; Heinz bodies, schistocytes, target cells, nucleated red cells, spherocytes, and polychromasia. This present study has shown a high prevalence of G6PD deficiency among children residing in Sokoto in the northwestern geopolitical zone of Nigeria. The study indicated a male sex bias in the prevalence of G6PD deficiency among the children studied. There is a need for the routine screening of children for G6PD deficiency in our environment, to allow for evidence-based management of these children and to ensure the avoidance of food, drugs, and infective agents that can potentially predispose these children to oxidative stress as well as diseases that deplete micronutrients that protect against oxidative stress. There is need to build capacity in our setting among pediatricians to ensure the effective management of children with G6PD deficiency.

Sickle cell disease in Africa: a neglected cause of early childhood mortality

Sickle cell disease (SCD) is common throughout much of sub-Saharan Africa, affecting up to 3% of births in some parts of the continent. Nevertheless, it remains a low priority for many health ministries. The most common form of SCD is caused by homozygosity for the β-globin S gene mutation (SS disease). It is widely believed that this condition is associated with very high child mortality, but reliable contemporary data are lacking. We have reviewed available African data on mortality associated with SS disease from published and unpublished sources, with an emphasis on two types of studies: cross-sectional population surveys and cohort studies. We have concluded that, although current data are inadequate to support definitive statements, they are consistent with an early-life mortality of 50%-90% among children born in Africa with SS disease. Inclusion of SCD interventions in child survival policies and programs in Africa could benefit from more precise estimates of numbers of deaths among children with SCD. A simple, representative, and affordable approach to estimate SCD child mortality is to test blood specimens already collected through large population surveys targeting conditions such as HIV, malaria, and malnutrition, and covering children of varying ages. Thus, although there is enough evidence to justify investments in screening, prophylaxis, and treatment for African children with SCD, better data are needed to estimate the numbers of child deaths preventable by such interventions and their cost effectiveness.

Prevalence of classic erythrocyte polymorphisms among 749 children in southern highland Rwanda

Classic erythrocyte polymorphisms were assessed by PCR-based methods among 749 children in southern highland Rwanda. Sickle cell trait, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and α(+)-thalassaemia were observed in 2.8%, 9.6%, and 15.1%, respectively. Malariologic parameters did not correlate with these traits. Haemoglobin concentrations were significantly reduced in α(+)-thalassaemia but only homozygosity (0.8%) was a rare cause of anaemia in this population. The frequencies of malaria-protective polymorphisms reflect the high altitude (1700-1800 metres) of the study area. α(+)-thalassaemia and G6PD deficiency have previously been underestimated in Rwanda which may be of importance in the diagnosis and treatment of common childhood diseases.

The Efficacy of a Neonatal Screening Programme in Decreasing the Hospitalization Rate of Patients with G6pd Deficiency in Southern Iran

Objective

To investigate whether a neonatal screening programme for G6PD deficiency has decreased hospitalization for acute haemolytic attack in the Fars province of southern Iran.

Methods

A total of 850 patients registered with G6PD deficiency were included in the study. Variables including age, sex, time and cause of hospitalization, cause of haemolytic crisis, positive history of blood transfusion, G6PD enzyme deficiency, blood urea nitrogen (BUN) and creatinine were recorded based on a standard questionnaire. All patients were analysed for G6PD enzyme level based on a quantitative test.

Results

Five hundred and fifty-three patients were hospitalized before the introduction of the neonatal screening programme (2001-2004) and 297 afterwards (2005-2008). Of those patients hospitalized after the introduction of the screening programme, 237 were wrongly classified as normal and 60 were recorded as having G6PD enzyme deficiency by the neonatal screening programme. The main causes of haemolytic crisis in G6PD-deficient patients were fava bean consumption (88.2%), underlying infection (10.9%) and drugs (0.8%).

Conclusion

Our study showed the effectiveness of the neonatal screening programme in decreasing the hospitalization rate.

Prevalence of sickle cell disease in a northeastern region of the Democratic Republic of Congo: what impact on transfusion policy?

Transfusion therapy may save the lives of patients with sickle cell disease (SCD), but it is also associated with a high risk of transmission of infection. The aims of this study were to determine the prevalence of SCD in a northeastern region of the Democratic Republic of Congo (DRC), and to define ways in which the procedures involved in the security of transfusions should be improved. During a 3-month period in 2006/2007, 520 samples of umbilical cord blood were obtained through neonatal screening in five health centres in Kisangani. The samples were analysed using an isoelectric focusing technique. The estimated prevalence of sickle cell trait and SCD in the population tested was 23.3 and 0.96%, respectively. These numbers will be presented for the attention of the health authorities in DRC with responsibility for SCD and they will be asked to consider improvements in treatment procedures for SCD, such as blood transfusions, as a public health priority.

High risk of severe anaemia after chlorproguanil-dapsone+artesunate antimalarial treatment in patients with G6PD (A-) deficiency

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common inherited human enzyme defect. This deficiency provides some protection from clinical malaria, but it can also cause haemolysis after administration of drugs with oxidant properties.

METHODS

The safety of chlorproguanil-dapsone+artesunate (CD+A) and amodiaquine+sulphadoxine-pyrimethamine (AQ+SP) for the treatment of uncomplicated P. falciparum malaria was evaluated according to G6PD deficiency in a secondary analysis of an open-label, randomized clinical trial. 702 children, treated with CD+A or AQ+SP and followed for 28 days after treatment were genotyped for G6PD A- deficiency.

FINDINGS

In the first 4 days following CD+A treatment, mean haematocrit declined on average 1.94% (95% CI 1.54 to 2.33) and 1.05% per day (95% CI 0.95 to 1.15) respectively in patients with G6PD deficiency and normal patients; a mean reduction of 1.3% per day was observed among patients who received AQ+SP regardless of G6PD status (95% CI 1.25 to 1.45). Patients with G6PD deficiency recipients of CD+A had significantly lower haematocrit than the other groups until day 7 (p = 0.04). In total, 10 patients had severe post-treatment haemolysis requiring blood transfusion. Patients with G6PD deficiency showed a higher risk of severe anaemia following treatment with CD+A (RR = 10.2; 95% CI 1.8 to 59.3) or AQ+SP (RR = 5.6; 95% CI 1.0 to 32.7).

CONCLUSIONS

CD+A showed a poor safety profile in individuals with G6PD deficiency most likely as a result of dapsone induced haemolysis. Screening for G6PD deficiency before drug administration of potentially pro-oxidants drugs, like dapsone-containing combinations, although seldom available, is necessary.