Hemoglobin S and Glucose-6-Phosphate Dehydrogenase Deficiency Coinheritance in AS and SS Individuals in Malaria-Endemic Region: A Study in Calabar, Nigeria

A community based study on haemoglobinopathies and G6PD deficiency among particularly vulnerable tribal groups in hard-to-reach malaria endemic areas of Odisha, India: implications on malaria control

BACKGROUND

Haemoglobinopathies and G6PD deficiency are inherited disorders found mostly in malaria-endemic areas among different tribal groups of India. However, epidemiological data specific to Particularly Vulnerable Tribal Groups (PVTGs), important for planning and implementing malaria programmes, is limited. Therefore, the present community-based study aimed to assess the prevalence of haemoglobinopathies and G6PD deficiency among the 13 PVTGs found in the state of Odisha, reporting the maximum malaria cases in the country.

METHODS

This cross-sectional study was conducted from July 2018 to February 2019 in 12 districts, home to all 13 PVTGs, in an estimated sample size of 1461, selected two-stage sampling method. Detection of haemoglobinopathies was done by the variant analyser. Screening of G6PD deficiency was carried out using DPIP method followed by quantification using spectrophotometry. The PCR-RFLP technology was used to determine variant of G6PD deficiency and haplotype analysis of sickle cell, while ARMS-PCR and GAP-PCR was used for detecting the mutation pattern in β-thalassaemia and α-thalassaemia respectively. The diagnosis of malaria was done by Pf-PAN RDT as point of care, followed by nPCR for confirmation and Plasmodium species identification.

RESULTS

The prevalence of sickle cell heterozygotes (AS) was 3.4%, sickle cell homozygous (SS) 0.1%, β-thalassaemia heterozygotes 0.3%, HbS/β-thalassaemia compound heterozygote 0.07%, HbS-α-thalassaemia 2.1%, G6PD deficiency 3.2% and malaria 8.1%. Molecular characterization of βS revealed the presence of Arab-Indian haplotype in all HbS cases and IVS 1-5 G → C mutation in all β-thalassaemia cases. In case of α-thal, αα/α-3.7 gene deletion was most frequent (38%), followed by αα/α-4.2 (18%) and α-3.7/α-3.7 (4%). The frequency of G6PD Orissa (131C → G) mutation was found to be 97.9% and G6PD Mediterranean (563C → T) 2.1%. Around 57.4% of G6PD deficient individuals and 16% of the AS were found to be malaria positive.

CONCLUSION

The present study reveals wide spread prevalence of sickle cell anaemia, α-thalassaemia, G6PD deficiency and malaria in the studied population. Moderate to high prevalence of G6PD deficiency and malaria warrants G6PD testing before treating with primaquine (PQ) for radical cure of Plasmodium vivax. Screening and counselling for HbS is required for the PVTGs of Odisha.

Evolutionary history of sickle-cell mutation: implications for global genetic medicine

Resistance afforded by the sickle-cell trait against severe malaria has led to high frequencies of the sickle-cell mutation [HBB; c.20T>A, p.Glu6Val; OMIM: 141900 (HBB-βS)] in most parts of Africa. High-coverage sequencing and genotype data have now confirmed the single African origin of the sickle-cell gene variant [HBB; c.20T>A, p.Glu6Val; OMIM: 141900 (HBB-βS)]. Nevertheless, the classical HBB-like genes cluster haplotypes remain a rich source of HBB-βS evolutionary information. The overlapping distribution of HBB-βS and other disease-associated variants means that their evolutionary genetics must be investigated concurrently. In this review: (1) we explore the evolutionary history of HBB-βS and its implications in understanding human migration within and out of Africa: e.g. HBB haplotypes and recent migration paths of the Bantu expansion, occurrence of ~7% of the Senegal haplotype in Angola reflecting changes in population/SCD dynamics, and existence of all five classical HBB haplotype in Cameroon and Egypt suggesting a much longer presence of HBB-βS in these regions; (2) we discuss the time estimates of the emergence of HBB-βS in Africa and finally, (3) we discuss implications for genetic medicine in understanding complex epistatic interactions between HBB-βS and other gene variants selected under environmental pressure in Africa e.g. variants in HBB, HBA, G6PD, APOL1, APOE, OSBPL10 and RXRA.

Sickle Cell Trait Modulates the Proteome and Phosphoproteome of Plasmodium falciparum-Infected Erythrocytes

The high prevalence of sickle cell disease in some human populations likely results from the protection afforded against severe Plasmodium falciparum malaria and death by heterozygous carriage of HbS. P. falciparum remodels the erythrocyte membrane and skeleton, displaying parasite proteins at the erythrocyte surface that interact with key human proteins in the Ankyrin R and 4.1R complexes. Oxidative stress generated by HbS, as well as by parasite invasion, disrupts the kinase/phosphatase balance, potentially interfering with the molecular interactions between human and parasite proteins. HbS is known to be associated with abnormal membrane display of parasite antigens. Studying the proteome and the phosphoproteome of red cell membrane extracts from P. falciparum infected and non-infected erythrocytes, we show here that HbS heterozygous carriage, combined with infection, modulates the phosphorylation of erythrocyte membrane transporters and skeletal proteins as well as of parasite proteins. Our results highlight modifications of Ser-/Thr- and/or Tyr- phosphorylation in key human proteins, such as ankyrin, β-adducin, β-spectrin and Band 3, and key parasite proteins, such as RESA or MESA. Altered phosphorylation patterns could disturb the interactions within membrane protein complexes, affect nutrient uptake and the infected erythrocyte cytoadherence phenomenon, thus lessening the severity of malaria symptoms.

Bibliometric analysis of global sickle cell disease research from 1997 to 2017

Introduction

Sickle cell disease is an autosomal recessive genetic disease caused by a single point mutation in the β-globin chain of the hemoglobin. It has been recognized by the World Health Organization as a public health priority since 2006.

Methods

The Scopus database was used in this study with the search descriptors: “sickle cell” and “sickle cell disease”. We applied common bibliometric indicators to evaluate the trend in scientific literature in sickle cell disease research.

Results

We retrieved a total of 19,921 pieces of scientific literature in the repertoire from 1997 to 2017. The Price law was fulfilled in the trend of production of scientific literature on SCD as the growth of scientific literature was more exponential (r = 0.9751; r² = 0.9509) than linear (r = 0.9721; r² = 0.9449). We observed a duplication time of 4.52 years. The Bradford core was made up of 69 journals with Blood at the top, publishing the greatest number of articles. The most productive institutions were mostly United States agencies and hospitals. The United States was the most productive country. The National Institute of Health was the most productive institution and also had the highest number of citations. Vichinsky E was the most productive author, while the most cited article was published by Circulation.

Conclusion

The growth of scientific literature in Sickle cell disease was found to be high. However, the exponential growth trend shows a “yet-to-be-explored” area of research. This study will be useful for physicians, researchers, research funders and policy-cum-decision makers.

Causes of morbidity and mortality among patients admitted in a tertiary hospital in southern Nigeria: A 6 year evaluation

BACKGROUND

Data on morbidity and mortality are essential in assessing disease burden, monitoring and evaluation of health policies. The aim of this study is to describe the causes of morbidity and mortality in the wards of University of Calabar Teaching Hospital (UCTH).

METHODS

The study took a retrospective approach evaluating causes of morbidity and mortality from 2012-2017. Causes of death were documented based on International Classification of Disease 10 (ICD-10). Data were retrieved from health records department, UCTH.

RESULTS

Overall, 2,198 deaths were recorded out of the 49,287 admissions during the study period giving a mortality rate of 4.5% comprising 1,152 (52.4%) males and 1,046 (47.6%) females. A greater number of males were admitted via accident and emergency. Age group 15-45 years had the highest number of admissions (57.9%) and deaths (37.7%), while age group >65 years recorded the highest number of deaths per admission (9.7% mortality rate). The broad leading causes of death were infectious and parasitic disease and diseases of the circulatory system (cardiovascular diseases) accounting for 22.7% and 15.8% of all deaths, respectively. However, diseases of the circulatory system recorded the highest number of deaths per admission (13.7% mortality rate). Overall, infectious diseases were the chief cause of mortality in adults while conditions originating from perinatal period were the major cause of death in children. Septicemia (6.0%), stroke (4.2%), liver diseases (4.1%), tuberculosis (3.7%), diabetes (3.6%) and HIV/AIDS (3.4%) were the specific leading cases of deaths. Sepsis, chronic diseases of the tonsil and adenoids and malaria were the specific leading causes of death in children, while sepsis, stroke and liver diseases were the leading cause of death in adults.

CONCLUSION

Most causes of deaths in this study are preventable. This study revealed double burden of communicable and non-communicable diseases.

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase: Do Single Nucleotide Polymorphisms Affect Hematological Parameters in HIV-Positive Patients?

This descriptive, cross-sectional study aimed at evaluating the prevalence of G6PD deficiency and the 376A ⟶ G, 202G ⟶ A single nucleotide polymorphisms (SNPs) among HIV patients attending care at a teaching hospital in Ghana and determine how the SNPs affect haematological profile in HIV. A total of 200 HIV-positive Ghanaians were recruited. Venous blood samples were obtained and complete blood count, and G6PD screening and genotyping for the 376A ⟶ G, 202G ⟶ A SNPs were performed. Out of the 200 participants, 13.0% (26/200) were G6PD-deficient based on the methemoglobin reductase technique, with 1.5% (3/200) and 11.5% (23/200) presenting with partial and full enzyme defect, respectively. Among the 13.0% participants with G6PD deficiency, 19.2% (5/26), 30.8% (8/26), and 19.2% (5/26) presented with 376A ⟶ G only (enzyme activity (EA): 1.19 U/g Hb), 202G ⟶A only (EA: 1.41 U/g Hb), and G202/A376 SNPs (EA: 1.14 U/g Hb), respectively. Having the 376A ⟶ G mutation was associated not only with lower red blood cell (RBC) count (3.38 × 106/µL (3.16-3.46) vs 3.95 × 106/µL (3.53-4.41), p = 0.010) but also with higher mean cell volume (MCV) (102.90 (99.40-113.0) vs 91.10 fL (84.65-98.98), p = 0.041) and mean cell haemoglobin (MCH) (33.70 pg (32.70-38.50) vs 30.75 pg (28.50-33.35), p = 0.038), whereas possessing the 202G ⟶ A mutation was associated with higher MCV only (98.90 fL (90.95-102.35) vs 91.10 fL (84.65-98.98), p = 0.041) compared to G6PD nondeficient participants. The prevalence of G6PD deficiency among HIV patients in Kumasi, Ghana, is 13.0% prevalence, comprising 1.5% and 11.5% partial and full enzyme defect, respectively, based on the methemoglobin reductase technique among HIV patients in Ghana. Among G6PD-deficient HIV patients, the prevalence of G202/A376 SNPs is 19.2%. The 376A ⟶ G mutation is associated not only with lower RBC count but also with higher MCV and MCH, whereas the 202G ⟶ A mutation is associated with higher MCV compared to the normal G6PD population.

Effects of Single and Double Mutants in Human Glucose-6-Phosphate Dehydrogenase Variants Present in the Mexican Population: Biochemical and Structural Analysis

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most frequent human enzymopathy, affecting over 400 million people globally. Worldwide, 217 mutations have been reported at the genetic level, and only 19 have been found in Mexico. The objective of this work was to contribute to the knowledge of the function and structure of three single natural variants (G6PD A+, G6PD San Luis Potosi, and G6PD Guadalajara) and a double mutant (G6PD Mount Sinai), each localized in a different region of the three-dimensional (3D) structure. In the functional characterization of the mutants, we observed a decrease in specific activity, protein expression and purification, catalytic efficiency, and substrate affinity in comparison with wild-type (WT) G6PD. Moreover, the analysis of the effect of all mutations on the structural stability showed that its presence increases denaturation and lability with temperature and it is more sensible to trypsin digestion protease and guanidine hydrochloride compared with WT G6PD. This could be explained by accelerated degradation of the variant enzymes due to reduced stability of the protein, as is shown in patients with G6PD deficiency.

Prevalence of asymptomatic malaria in HIV-infected subjects on cotrimoxazole antimalarial prophylaxis attending a tertiary health care center in southern Nigeria: a cross-sectional study

Introduction

Co-infection has become a major contributor to increased burden of morbidity and mortality in HIV infection. The aim of this study was to assess the prevalence of asymptomatic malaria in the HIV-infected subjects on antimalarial prophylaxis and provide information to improve management of HIV subjects.

Methods

This was a cross-sectional study with a purposive sampling. Microscopy method was used for the confirmation of malaria parasitemia status. The study was performed in University of Calabar Teaching Hospital, Calabar, Cross River State, Nigeria, a major tertiary health institution within the period of January to June 2016 involving 100 participants.

Results

The majority (65%) of the study participants were females. The majority of the studied population belonged to the age range 33-38 years old. Most (45%) of the patients had CD4 count ≥500 cells/µL. The prevalence of asymptomatic malaria was found to be 13% (13/100). The distribution of asymptomatic malaria based on gender and age were found not to be statistically significant (P>0.05). Subjects with CD4 count in the range of 200-499 cells/µL had the highest prevalence (24.39%) of asymptomatic malaria.

Conclusions

Considering that all the studied participants were on antimalarial prophylaxis, it signals a public health concern to employ more intensive preventive methods in addition to antimalaria prophylaxis.