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

BACKGROUND: Stroke is a devastating complication of sickle cell anemia (SCA) and can be predicted through abnormally high cerebral blood flow velocity using transcranial Doppler Ultrasonography (TCD). The evidence on the role of alpha‐thalassemia and glucose‐6‐phosphate dehydrogenase (G6PD) deficiency in the development of stroke in children with SCA is conflicting. Thus, this study investigated the association of alpha‐thalassemia and G6PD(A(−)) variant with abnormal TCD velocities among Nigerian children with SCA. METHODS: One hundred and forty‐one children with SCA were recruited: 72 children presented with normal TCD (defined as the time‐averaged mean of the maximum velocity: < 170 cm/s) and 69 children with abnormal TCD (TAMMV ≥ 200 cm/s). Alpha‐thalassemia (the α‐3.7 globin gene deletion) was determined by multiplex gap‐PCR, while G6PD polymorphisms (202G > A and 376A > G) were genotyped using restriction fragment length polymorphism—polymerase chain reaction. RESULTS: The frequency of α‐thalassemia trait in the children with normal TCD was higher than those with abnormal TCD: 38/72 (52.8%) [α‐/ α α: 41.7%, α ‐/ α ‐: 11.1%] versus 21/69 (30.4%) [α‐/ α α: 27.5%, α ‐/ α ‐: 2.9%], and the odds of abnormal TCD were reduced in the presence of the α‐thalassemia trait [Odds Ratio: 0.39, 95% confidence interval: 0.20–0.78, p = 0.007]. However, the frequencies of G6PDA(−) variant in children with abnormal and normal TCD were similar (11.6% vs. 15.3%, p = 0.522). CONCLUSION: Our study reveals the protective role of α‐thalassemia against the risk of abnormal TCD in Nigerian children with SCA.