Identificação de haplótipos do gene da globina beta s (βs) em pessoas com anemia falciforme do Estado do Amapá

Abstract

Sickle cell anemia (SCA) or HbSS is a hereditary, hematologic, multifactorial disease, with high prevalence worldwide; its cause is a mutation in the sixth codon of the beta globin gene (βS), where there are several polymorphisms, among which there are five main haplotypes of the βS gene: Arabic - Indian/Saudi, Senegal, Benin, Bantu and Cameroon; between the characteristics of βS haplotypes there is the possibility of influencing the variability and clinical intensity of SCA, in such a way, related to studies on the ethnic origin of the population. From the importance of these haplotypes and yet there is almost no molecular studies concerning SCA in the State of Amapá, this research aimed to determine the haplotypes of the globin gene βS present in people with SCA from Amapá. Blood samples (n=46) collected from patients with HbSS were submitted to laboratory screening of hemoglobins (electrophoresis in alkaline pH and acid; HPLC), then DNA extraction for the confirmation of HbSS and determination of haplotypes by PCR-RFLP, using restriction endonucleases (Xmn I, Hind III, Hinc II and Hinf I) for analysis of six polymorphic sites. All analyzes were performed at LHGDH/IBILCE - UNESP/São José do Rio Preto-SP. According to the alleles identified, it was observed that the predominance of Bantu haplotype (65.2%) followed by Benin (21.8%) and Senegal (13%) haplotypes. Regarding genotypes, the majority was identified as Bantu/Bantu (47.8%), Bantu/Benin (21.7%), Bantu/Senegal (13.0%), Benin/Senegal (8.7%), Benin/Benin (6.5%) and less frequently Senegal/Senegal (2.2%). It was observed that it were identified three haplotypes characteristic of African ethnicity, with high frequency of Senegal and Benin diverging from the majority of Brazilian studies, which is in agreement with reports on African migration to the northern region. It is noted the absence of atypical, which indicates low genetic variability in data from people who live in Amapá, suggesting concentration and semi-isolation of the founding groups with little mixing