Association of alpha-thalassemia, TNF-alpha (-308GNA) and VCAM-1 (c.1238GNC) gene polymorphisms with cerebrovascular disease in a newborn cohort of 411 children with sickle cell anemia.

Abstract

Cerebrovascular disease (CVD) is a severe complication associatedwith sickle cell anemia. Abnormal transcranial Doppler (TCD) identifies some children at high risk, but other markers would be helpful. This cohort study was aimed at evaluating the effects of genetic biomarkers on the risk of developing CVDin children fromMinasGerais, Brazil. Clinical and hematological data were retrieved from children's records. Outcomes studied were overt ischemic stroke and CVD (overt ischemic stroke, transient ischemic attack, abnormal TCD, or abnormal cerebral angiography). Out of 411 children, 386 (93.9%) had SS genotype, 23 (5.6%) had Sβ0-thal and two had severe Sβ+-thal (0.5%). Frequency of CVD was lower in Sβ-thal group (p= 0.05).NoeffectofVCAM-1polymorphism on stroke or CVD risks was detected. Cumulative incidence of stroke was significantly higher for children with TNF-α A allele (p = 0.02) and lower for children with HBA deletion (p = 0.02). However, no association between CVD and TNF-α -308GNA was found. CVD cumulative incidence was significantly lower for children with HBA deletion (p= 0.004). This study found no association between VCAM1 c.1238GNC and stroke. An association between stroke and TNF-α -308A allele has been suggested. Our results have confirmed the protective role of HBA deletion against stroke and CVD.