title: Mutational Profile of Homozygous β-Thalassemia in Rio de Janeiro, Brazil.
abstract: β-Thalassemia (β-thal) is a hemolytic anemia that is caused by point mutations in most cases. The Brazilian population is highly heterogeneous and knowledge of the mutations that make up the genotypic profile of individuals can contribute information about the formation of the population and clinical condition of patients. In this study, we evaluated the mutations present in homozygous β-thal patients from Rio de Janeiro, Brazil. We analyzed 24 samples of peripheral blood of patients with homozygous β-thal. To identify the mutations, we carried out allele-specific-polymerase chain reaction (AS-PCR) and DNA sequencing. We found 11 different mutations on the β-globin gene. Among the most frequent mutations observed were HBB: c.92 + 6T>C, followed by HBB: c.93-21G>A, HBB: c.118C>T and HBB: c.92 + 1G>A. We also identified the rare mutation HBB: c.75T>A that was reported in an individual carrying Hb S (HBB: c.20A>T)/β-thal (HBB: c.75T>A) but not in Brazilian thalassemic patients, thus, this is the first report of this mutation in Brazilian β-thal patients. For its multiethnic character, Brazil has different mutations that cause β-thal and that are distributed with different frequencies according to the regions of the country. Our findings contribute to the description of the mutational profile of Brazilian thalassemic patients, showing wide heterogeneity and genetic variability.
authors.affiliation: a Department of Biology , Hemoglobin and Hematologic Genetic Diseases Laboratory, São Paulo State University (UNESP) , São Paulo , Brazil.
authors.forename: Gisele C S
authors.initials: GCS
authors.lastname: Carrocini
authors.affiliation: b Center of Biological and Health Sciences , West Federal University of Bahia (UFOB) , Barreiras , Bahia , Brazil.
authors.forename: Larissa P R
authors.initials: LPR
authors.lastname: Venancio
authors.affiliation: c State Institute of Hematology 'Arthur de Siqueira Cavalcanti' (HEMORIO) , Rio de Janeiro , Brazil.
authors.forename: Viviani L R
authors.initials: VLR
authors.lastname: Pessoa
authors.affiliation: c State Institute of Hematology 'Arthur de Siqueira Cavalcanti' (HEMORIO) , Rio de Janeiro , Brazil.
authors.forename: Clarisse L C
authors.initials: CLC
authors.lastname: Lobo
authors.affiliation: a Department of Biology , Hemoglobin and Hematologic Genetic Diseases Laboratory, São Paulo State University (UNESP) , São Paulo , Brazil.
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Bonini-Domingos
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003062:Codon; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007438:Introns; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic; D055815:Young Adult; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000628:therapy
chemical_list: D003062:Codon; D055544:beta-Globins
keywords: hemoglobin (Hb); hemolytic anemia; molecular genetics; mutations; β-Thalassemia (β-thal)