Background: Sickle cell disease (SCD) is the commonest genetic disorder worldwide with a global prevalence of 20-25 million. About 12-15 million affected persons are in Sub-Sahara Africa with Nigeria bearing the highest burden of people living with sickle cell disease. SCD is a disease characterized as an autosomal, recessive, heterogeneous, and a monogenetic disorder caused by an A-to-T point mutation in the β-globin gene responsible for the production of abnormal hemoglobin S (HbS), which polymerizes in the deoxygenated state and results in the sickling of erythrocytes.  Haemoglobin variants are mutant forms of haemoglobin in a population usually occurring as a result of genetic changes in specific genes, or globins that causes change on alterations in the amino acid. They could affect the structure, behavior, the production rate and the stability of the specific gene. Well-known haemoglobin variants such as sick-cell anaemia are responsible for diseases and are considered haemoglobinopathies. Other variants cause no detectable pathology and are thus considered as non-pathological variants. Aim: The study is aimed at evaluating the burden of sickle cell disease and other haemoglobin variants in Calabar, South-South Nigeria. Methods: This is a retrospective study done at the haematology laboratory of University of Calabar Teaching Hospital, Calabar. Cellulose acetate electrophoresis at alkaline pH was used for the evaluation of haemoglobinopathies. The data were entered into Microsoft Excel 2016 spreadsheet and analysed with the IBM SPSS Version 22. Data were summarized into percentage of different phenotypes. Results: Results of the total 3648 haemoglobin electrophoresis recorded, 1368 (37.50%) were male while the remaining 2280 (62.5%) females given a male to female ratio of 1:1.7. Five haemoglobin phenotypes were identified as HbAA, HbAS, HbAC, HbSC and HbSS. The overall average values of their prevalence were HbAA 64.78%, HbAS 32.62%, HbSS 2.14%, HbAC 0.33%, HbSC 0.14%. Thus, the prevalence of SCD (Prevalence of HbSS+HbSC) was 2.28%. The highest proportion of SCD was observed in 2011 with least in 2016 and 2017 respectively. Conclusion: The prevalence of SCD and other haemoglobin variants in Calabar is similar to that of the national prevalence rate. There is need for continuous enlightenment and premarital counselling on the pattern of inheritance of SCD most especially with the increased burden of sickle traits in the environment has reported in this study.

Background Sickle cell anemia (SCA) is a hypercoagulable state characterized by a significant alteration in hemostatic parameters that may predispose to increased risk of vaso‐occlusive crisis (VOC). The role of von Willebrand factor (VWF) in the pathogenesis of VOC has not been fully investigated in Nigeria. Objective The objective of this study was to evaluate the level of VWF in subjects with sickle cell disease (SCD) in Calabar, Nigeria, to determine its role in the pathogenesis of VOC. Methods This was a comparative study carried out at the University of Calabar Teaching Hospital, Calabar, Nigeria. Sixty patients with SCA in VOC and 50 healthy controls were included. VWF levels were measured using Assaypro enzyme‐linked immunosorbent assay kits. Results The mean age of patients with SCA in VOC and controls was 23.5 ± 7.2 years and 26.5 ± 5.6 years, respectively. The means (standard deviations) of VWF in patients in VOC and controls were 2.52 ± 0.34 IU/mL and 1.41 ± 0.23 IU/mL, respectively. There was no correlation of hematocrit and VWF in VOC ( r = −0.034; P = .80), while there was a modest inverse correlation in controls. Conclusions Levels of VWFare elevated in a VOC state and thus may be implicated in the pathogenesis of VOC.

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