alpha-Globin genes: thalassemic and structural alterations in a Brazilian population

Wenning, M.R.S.C.; Kimura, Eiichiro; Costa, Fernando Ferreira; Saad, Sara T.O.; Gervásio, Sirlei; Jorge, Susan E.; Borges, Eliana Lourenço; Silva, N.M.; Sonati, M.F.

doi:10.1590/s0100-879x2000000900008

Cited by 24 publications

(33 citation statements)

References 22 publications

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“…In our results, the frequency of thalassemia was lower among patients with CVD, but with no significant difference when compared to the ones without cerebrovascular involvement. Furthermore, only 15.8% had α-thalassemia compared to the reported prevalence of 20 to 25% in Afro-Brazilian population with SCA 17 . An increased HbF concentration can ameliorate SCA severity.…”

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confidence: 59%

Genetic polymorphisms and cerebrovascular disease in children with sickle cell anemia from Rio de Janeiro, Brazil

Filho

Leite

Moura

et al. 2011

Arq. Neuro-Psiquiatr.

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The aim of the present work was to examine possible genetic risk factors related to the occurrence of cerebrovascular disease (CVD) in Brazilian population, the frequency of β S -globin gene haplotypes and co-inheritance with α-thalassemia (-α 3.7kb ) and single nucleotide polymorphism of methylenetetrahydrofolate reductase (MTHFR-C677T), Factor V Leiden (FV-G1691A) and prothrombin (PT-G20210A) genes in children from Rio de Janeiro. Ninety four children with sickle cell anemia (SCA) were included, 24 patients with cerebrovascular involvement and 70 patients without CVD as control group. The mean age of children at the time of the cerebrovascular event was similar to the control group. The frequency of -α 3.7kb thalassemia was similar in both groups (p=0.751). Children with Bantu/Atypical β S -globin gene haplotype presented 15 times more chance (OR=15.4 CI 95% 2.9-81.6) of CVD than the other β S -globin gene haplotypes. The C677T polymorphism of MTHFR gene was similar in both groups (p=0.085). No mutation in the FV Leiden or PT genes was found. A large study seems necessary to establish the role of these genetic polymorphisms in Brazilian miscegenated population. Key words: sickle cell anemia, cerebrovascular disease, alpha-thalassemia, beta-globin haplotypes, genetic polymorphism.Polimorfismos genéticos e doença cerebrovascular em crianças com anemia falciforme do Rio do Janeiro, Brasil RESUMO Avaliar o papel da talassemia alfa (-α 3.7kb ), dos haplótipos da globina β S , e mutações nos genes da metileno-tetrahidrofolato redutase (MTHFR-C677T), fator V de Leiden (FV-G1691A) e protrombina (PT-G20210A) como fatores de risco para a doença cerebrovascular em pacientes com anemia falciforme. Foi realizado um estudo de caso controle com 94 crianças portadoras de anemia falciforme, 24 com doença cerebrovascular (DCV) e 70 sem DCV como grupo controle. A frequência de talassemia -α 3.7kb foi semelhante em ambos os grupos (p=0,751). Crianças portadoras do haplótipo Bantu/Atípico da globina β S apresentam 15 vezes mais chances de desenvolverem DCV (OR=15,4 IC 95% 2,9-81,6) do que os outros haplótipos. A frequência do polimorfismo MTHFR-C677T foi semelhante em ambos os grupos (p=0,085) e não foi observada mutação nos genes fator V e protrombina. Estudos com maior número de casos são necessários para esclarecer o papel desses polimorfismos genéticos na nossa população. Palavras-chave: anemia falciforme, acidente vascular cerebral, talassemia alfa, globinas beta, polimorfismo genético.

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confidence: 59%

Genetic polymorphisms and cerebrovascular disease in children with sickle cell anemia from Rio de Janeiro, Brazil

Filho

Leite

Moura

et al. 2011

Arq. Neuro-Psiquiatr.

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“…They are all encountered in Mediterranean populations. In Brazil, the -a 3.7 deletion has been frequently found in the Black population (10,11), and the --MED and -(a) 20.5 deletions have sporadically been described (12,13). One family with the nondeletional form a HphI a has been recently reported (13).…”

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confidence: 99%

High prevalence of alpha-thalassemia among individuals with microcytosis and hypochromia without anemia

Borges

Wenning

Kimura

et al. 2001

Braz J Med Biol Res

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In order to determine the contribution of a-thalassemia to microcytosis and hypochromia, 339 adult outpatients seen at Unicamp University Hospital (with the exception of the Clinical Hematology outpatient clinics), who showed normal hemoglobin (Hb) levels and reduced mean corpuscular volume and mean corpuscular hemoglobin, were analyzed. Ninety-eight were Blacks (28.9%) and 241 were Caucasians (71.1%). In all cases, Hb A 2 and F levels were either normal or low. The most common deletional and nondeletional forms of a-thalassemia [-a 3.7 , -a 4.2 , --MED , -(a) 20.5 , a HphI a, a NcoI a, aa NcoI and a TSAUDI ] were investigated by PCR and restriction enzyme analyses. A total of 169 individuals (49.9%) presented a-thalassemia: 145 (42.8%) were heterozygous for the -a 3.7 deletion (-a 3.7 /aa) and 18 (5.3%) homozygous (-a 3.7 /-a 3.7 ), 5 (1.5%) were heterozygous for the nondeletional form a HphI a (a HphI a/aa), and 1 (0.3%) was a --MED carrier (--MED /aa). Among the Blacks, 56 (57.1%) showed the -a 3.7 / aa genotype, whereas 12 (12.2%) were -a 3.7 /-a 3.7 and 1 (1.0%) was an a HphI a carrier; among the Caucasians, 89 (36.9%) were -a 3.7 /aa, 6 (2.5%) had the -a 3.7 /-a 3.7 genotype, 4 (1.7%) presented the nondeletional form (a HphI a/aa), and 1 (0.4%) was a --MED carrier. These results demonstrate that a-thalassemia, mainly through the -a 3.7 deletion, is an important cause of microcytosis and hypochromia in individuals without anemia. These data are of clinical relevance since these hematological alterations are often interpreted as indicators of iron deficiency.

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“…Although α-thalassemia is present throughout the world, its distribution varies greatly among different populations. In Brazil, most of the recognized α-thalassemia mutations involve deletions of one α-globin gene (α + -thalassemias), although several cases of α 0 -thalassemias have been reported in the literature (8)(9)(10)(11)(12). It has been shown that the -α 3.7 deletion is the most frequent mutation in the Brazilian population, occurring in 20-25% of the black population in the Southeastern region of the country (13).…”

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Characterization of alpha thalassemic genotypes by multiplex ligation-dependent probe amplification in the Brazilian population

Suemasu

Kimura

Oliveira

et al. 2011

Braz J Med Biol Res

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alpha-Globin genes: thalassemic and structural alterations in a Brazilian population

Cited by 24 publications

References 22 publications

Genetic polymorphisms and cerebrovascular disease in children with sickle cell anemia from Rio de Janeiro, Brazil

Genetic polymorphisms and cerebrovascular disease in children with sickle cell anemia from Rio de Janeiro, Brazil

High prevalence of alpha-thalassemia among individuals with microcytosis and hypochromia without anemia

Characterization of alpha thalassemic genotypes by multiplex ligation-dependent probe amplification in the Brazilian population

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