Absence of Association Between TNF α Polymorphysm and Cerebral Large Vessel Abnormalities in Adults with Sickle Cell Anemia

Purpose: Stroke is a common and serious complication of sickle cell disease (SCD) affecting children as well as adults. Recent reports suggested that promoter region polymorphism in the tumour necrosis factor alpha (TNF-α) gene at position −308 is an important risk factor for large vessel stroke in children with SCD. The role of TNF-α polymorphism in the frequency of magnetic resonance angiography (MRA) abnormalities in adults with SCD is still uncertain. Our objective was to evaluate TNF-α polymorphism in adults with SCD from a tertiary University-based hospital in Sao Paulo, Brazil and correlate them to brain magnetic resonance imaging (MRI) and MRA findings.

Casuistic and Methods: The determination of the G-308A polymorphism of the TNF-α gene was performed in forty-nine adult patients with SCD followed in our outpatient clinic. All subjects were evaluated with brain MRI and MRA to determine the presence of previous stroke, arterial tortuosity and intracranial stenosis

Results: Thirty-three patients (67.3%) had abnormal brain MRA scans (intracranial stenosis or arterial tortuosity). Eight patients (16.3%) had intracranial stenosis on MRA and 29 (59.2%) showed arterial tortuosity. Forty one patients (83.7%) had the GG TNF-α (−308) genotype and eight had the GA genotype. There were no cases of AA genotype. There was no correlation between homozygosis for the TNF-α (−308) G allele and MRA abnormalities.

Conclusion: Although TNF-α (−308) polymorphism has been considered a potential predictor of genetic risk for stroke in children with SCA, we found no association between the polymorphism and large vessel abnormalities in adults with sickle cell disease. (FAPESP: 04/04498-4)