Association of alpha-thalassemia and Glucose-6-Phosphate Dehydrogenase deficiency with transcranial Doppler ultrasonography in Nigerian children with sickle cell anemia

Genetic Modifiers of Stroke in Patients with Sickle Cell Disease-A Scoping Review

Sickle cell disease (SCD) clinically manifests itself with a myriad of complications. Stroke, both ischemic and hemorrhagic, as well as silent white matter changes, occurs at a relatively high prevalence. Understanding why and in whom stroke is most likely to occur is critical to the effective prevention and treatment of individuals with SCD. Genetic studies, including genome- and exome-wide association studies (GWAS and EWAS), have found several key modifiers associated with increased stroke/stroke risk in SCD via mechanisms including Hemoglobin F (HbF) modulation, inflammation, cellular adhesion, endothelial disruption, and hemolysis. We present a review on the modifiers that have most clearly demonstrated an association to date. More studies are needed to validate other potential polymorphisms and identify new ones. Incorporating gene-focused screenings in clinical care could provide avenues for more targeted, more effective, and less toxic prevention of stroke in this population. The data from this review will be used to inform the initial GWAS performed by the International Hemoglobinopathy Research Network (INHERENT) consortium.

Characterization of a cohort of Angolan children with sickle cell anemia treated with hydroxyurea

BACKGROUND

Sickle Cell Anemia (SCA) is a monogenic disease, although its severity and response to treatment are very heterogeneous.

OBJECTIVES

This study aims to characterize a cohort of Angolan children with SCA and evaluate their response to hydroxyurea (HU) treatment and the potential side effects and toxicity.

METHODS

The study enrolled 215 patients between 3 and 12 years old before and after the administration of HU, at a fix dose of 20 mg/kg/day for 12 months.

RESULTS

A total of 157 patients started HU medication and 141 of them completed the 12-month treatment. After initiating HU treatment, the frequency of clinical events decreased (transfusions 53.4 %, hospitalizations 47.1 %). The response to HU medication varied among patients, with some experiencing an increase in fetal hemoglobin (HbF) of <5 %. The mean increase in HbF was 11.9 %, ranging from 1.8 % to 31 %. Responders to HU treatment were 57 %, inadequate responders 38.7 % and non-adherent 4.2 %. No clinical side effects related to HU were reported. Hematological toxicities were transient and reversible. Children naïve to HU and with lower HbF reported higher number of hospitalizations caused by malaria infection. During HU treatment, the frequency of malaria episodes did not appear to be affected by HbF levels.

CONCLUSIONS

the present study provided a valuable contribution to the understanding of the clinical and laboratory profiles of Angolan children with SCA. These findings support the evidence that the implementation of prophylactic measures and treatment with HU is associated with increased survival in children with SCA.

Cerebral artery conditional blood velocity in sickle cell disease: a multicentre study and evidence for active treatment

OBJECTIVE

To obtain multicentre data on the prevalence of normal, high or conditional (intermediate) blood velocity in the cerebral arteries among children with sickle cell disease (SCD) in Nigeria.

DESIGN

A prospective observational study in five tertiary healthcare institutions. By transcranial Doppler (TCD) ultrasonography, cerebral artery peak systolic blood velocity (PSV) was determined in 193 children with SCD and time averaged mean of the maximum blood velocity (TAMMV) in a different cohort of 115 children. This design was to make the findings relevant to hospitals with TCD equipment that measure either PSV or TAMMV.

SETTING

Nigeria.

PARTICIPANTS

308 children (126 girls, 182 boys; age 2-16 years).

MAIN OUTCOME MEASURES

Percentage of children with SCD who have normal, high or intermediate (often termed conditional) PSV or TAMMV.

RESULTS

In the cohort of 193 children, PSV was normal in 150 (77.7%), high in 7 (3.6%) and conditional in 36 (18.7%). In the cohort of 115 children, TAMMV was normal in 96 (84%), high in 7 (6%) and conditional in 12 (10%). There were no significant differences in gender or age distribution between the PSV and TAMMV cohorts. Altogether, cerebral artery blood velocity was normal in 246/308 children (80%), high in 14 (4.5%) and conditional in 48 (15.5%).

CONCLUSION

Since conditional blood velocity in cerebral arteries can progress to high values and predispose to stroke, the proportion of children with SCD who are affected (15.5%) raises the question of whether regular monitoring and proactive intervention ought to be the standard of care.