Relação entre os polimorfimos dos genes da mthfr c677t e da enos t786c, a velocidade do fluxo sanguíneo encefálico e o risco de acidente vascular encefálico em pacientes falciformes

Abstract

Sickle cell disease is a genetic disorder that occurs primarily in blacks and affects more than 6 million births a year around the world. Sickle cell disease (SCD) includes sickle cell anemia (SCA) and other hemoglobinopathies. SCA can present a number of complications in these patients, including cerebrovascular accident. The pathophysiological basis for ischemic stroke has not yet been fully elucidated, since there are multiple factors involved in this process. In order to assess the primary risk of stroke in sickle children and adolescents, Transcranial Doppler ultrasonography (DTC) is considered to be the most appropriate prognostic tool clinically available, capable of predicting the increased risk of stroke. Several polymorphisms have now been studied in these patients, including methylenetetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase (eNOS), although many are controversial, but this study is unprecedented in the relation between the velocity of the encefálico blood flow and these polymorphisms, as well as biochemical and hematological determinants. The aim of this study was to investigate whether there is a relationship between these two polymorphisms, VFSE and the risk of stroke in sickle cell patients. This is a cross-sectional observational study, carried out at the Hemocentro de Alagoas (HEMOAL) with the participation of 151 patients, between 2 and 16 years of age, of both sexes, diagnosed with SCD, and a control population of 64 people without the disease. It has been observed that there is a relationship between the polymorphisms of the MTHFR genes C677T and eNOS T786C with the velocity of encefalic blood flow and the risk of stroke in patients with SCD. The type of hemoglobinopathy most affected with increased blood flow velocity is HBSS (sickle cell anemia). There is no relation between increased encephalic blood flow velocity with age or sex in sickle cell patients. The risk of stroke in sickle cell patients is classified, respectively, in the following extracts: a) low intermediate; b) imminent; c) increased; and d) variable with reduced value. There is a correlation between encefálico blood flow velocity and mean corpuscular hemoglobin concentration, indirect bilirubin and direct bilirubin in sickle cell patients. The most prevalent polymorphisms for the MTHFR C677T genes and the eNOS T786C gene are the CC type genotypes. Patients with mutant polymorphism (TT) are at increased risk of stroke.