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Previous issue date: 2010-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Beta thalassemia arises as a consequence of the reduction (?+, ?++, ?silent) or absence (?0) of beta globin chain synthesis and results from a number of mechanisms that lead to genetic defects. The inheritance of beta thalassemia is characterized by the existence of heterozygous individuals, compound heterozygotes, homozygotes and those with coinheritance of beta thalassemia allele and other thalassemias and/or hemoglobin variants. The aim of this study was to perform molecular and laboratory characterization of beta thalassemia in heterozygous and homozygous individuals and in those with coinheritance of S beta thalassemia. A total of 48 individuals were included (35 heterozygotes, 4 homozygotes and 9 S beta thalessemia carriers) referred to the Integrated Laboratory of Clinical Analyses of the Federal University of Rio Grande do Norte (UFRN) and the Hematology Ambulatory Facility of the Dalton Barbosa Cunha Hemocenter (Hemonorte Natal, Brazil). Peripheral blood samples form each patient underwent the following laboratory examinations: erythrogram, hemoglobin
electrophoresis at alkaline pH, measurements of Hb A2, Fetal Hb and serum ferritin. DNA was extracted using the illustra blood genomicPrep Mini Spin Kit and molecular characterization was performed by the PCR/RFLP technique, which involves digestion with specific restriction enzymes for IVS-1 nt 1 (G?A), IVS-1 nt 6 (T?C) and codon 39 (CAG?TAG) mutations. Of the 35 heterozygotes, 37.1% showed IVS-1 nt 6 mutation, 42.9% IVS-1 nt 1 and 20% were carriers of other mutations not identified by the technique used. The four homozygous patients presented with the IVS-1 nt 6 mutation, while 66.7% of
the individuals with S beta thalassemia had the IVS-1 nt 1 mutation. Codon 39 was not detected in any of the patients investigated. Of the thallasemic alleles found, 40.4% were IVS-
1 nt 1, 40.4% IVS-1 nt 6 and 19.2% were not identified. Laboratory data showed that the heterozygotes exhibited microcytosis and hypochromia, evidenced by MCV ranging from 57 to 75fL and MCH from 15.9 to 23.6 pg. Hemoglobin A2 varied between 3.7 and 7.2%. The homogygotes also showed reduced MCV and MCH and elevated HbA2.. Comparison of laboratory data between heterozygous individuals with IVS-1 nt 1 and IVS-1 nt 6 mutations showed that heterozygotes for the IVS1-1 mutation had significantly lower mean MCV and MCH (p = 0.023 and 0.007, respectively) and significantly higher hemoglobin A2 (p < 0.001) when compared to heterozygotes for the IVS-1 nt 6 mutation. PCR/RFLP was useful in identifying the presence or absence of IVS-1 nt 6, IVS-1 nt 1 and codon 39 mutations in most of the patients investigated here. This is the first study conducted in the state of Rio Grande do Norte, Brazil aimed at identifying beta thalassemia mutations and represents an important contribution to the knowledge regarding the molecular profile of beta thalassemia in our country / A talassemia beta ocorre devido ? diminui??o (?+, ?++, ?silent) ou aus?ncia (?0) de s?ntese de cadeias beta de globina e ? decorrente de v?rios mecanismos que provocam o defeito
gen?tico. A heran?a da talassemia beta ? caracterizada pela exist?ncia de indiv?duos heterozigotos, heterozigoto compostos, homozigotos e portadores de intera??o entre o alelo
talass?mico beta e outras talassemias e/ou variantes de hemoglobina. O objetivo principal deste estudo foi realizar a caracteriza??o molecular e laboratorial em indiv?duos heterozigotos e homozigotos da talassemia beta e em portadores da intera??o hemoglobina S/talassemia
beta. Foram inclu?dos 48 indiv?duos (35 heterozigotos, 4 homozigotos e 9 com intera??o HbS/talassemia beta) atendidos no Laborat?rio Integrado de An?lises Cl?nicas (UFRN) e no
Ambulat?rio de Hematologia do Hemocentro Dalton Barbosa Cunha (Hemonorte Natal/RN). As amostras de sangue perif?rico de cada paciente foram submetidas aos seguintes exames laboratoriais: eritrograma, eletroforese de hemoglobina em pH alcalino, dosagem das hemoglobinas A2 e Fetal, e ferritina s?rica. O DNA foi extra?do utilizando-se o kit blood
genomicPrep Mini Spin e a caracteriza??o molecular foi realizada atrav?s da t?cnica PCR/RFLP mediante digest?o com enzimas de restri??o espec?ficas para as muta??es IVS-1 nt 1 (G?A), IVS-1 nt 6 (T?C) e nonsense c?don 39 (CAG?TAG). Dentre os 35 heterozigotos, 37,1% apresentaram a muta??o IVS-1 nt 6, 42,9% a IVS-1 nt 1 e 20% eram portadores de outras muta??es n?o identificadas com a t?cnica utilizada. Os quatro pacientes
homozigotos apresentaram a muta??o IVS-1 nt 6, enquanto 66,7% dos indiv?duos com intera??o HbS/talassemia beta tinham a muta??o IVS-1 nt 1. A c?don 39 n?o foi detectada em
nenhum dos pacientes investigados. Dentre os alelos talass?micos encontrados, 40,4% eram IVS-1 nt 1, 40,4% eram IVS-1 nt 6 e 19,2% n?o foram identificados. Em rela??o aos dados laboratoriais, os heterozigotos apresentaram microcitose e hipocromia evidenciada pelo VCM variando de 57 a 75fL, e o HCM, entre 15,9 a 23,6 pg. A hemoglobina A2 variou de 3,7 a
7,2%. Os homozigotos tamb?m apresentaram VCM e HCM reduzidos e HbA2 elevada. Ao comparar os dados laboratoriais entre os indiv?duos heterozigotos para as muta??es IVS-1 nt 1
e IVS-1 nt 6 observou-se que os heterozigotos da muta??o IVS1-1 apresentaram valores m?dios de VCM e HCM significativamente menores (p = 0,023 e 0,007, respectivamente) e hemoglobina A2 significativamente mais elevados (p < 0,001) quando comparados aos heterozigotos da muta??o IVS-1 nt 6. A t?cnica de PCR/RFLP se mostrou ?til para a identifica??o da presen?a ou aus?ncia das muta??es IVS-1 nt 6, IVS-1 nt 1 e ?0 c?don 39 na maioria dos pacientes investigados na pesquisa. O presente estudo ? o primeiro trabalho realizado no estado do Rio Grande do Norte para identifica??o das muta??es da talassemia beta, e constitui importante contribui??o para o conhecimento do perfil molecular da talassemia beta em nosso pa?s
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13454 |
| Date | 25 February 2010 |
| Creators | Silveira, Zama Messala Luna da |
| Contributors | CPF:15591360491, http://lattes.cnpq.br/9869053526045053, Schimieguel, Dulce Marta, CPF:65349598953, http://lattes.cnpq.br/6361482547166270, Ara?jo, Aderson da Silva, CPF:64073904000, http://lattes.cnpq.br/9615780257704881, Medeiros, Tereza Maria Dantas de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias Farmac?uticas, UFRN, BR, Bioan?lises e Medicamentos |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/embargoedAccess |
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