Mutations of Bruton's tyrosine kinase gene in Brazilian patients with X-linked agammaglobulinemia

Mutations in Bruton's tyrosine kinase (BTK) gene are responsible for X-linked agammaglobulinemia (XLA), which is characterized by recurrent bacterial infections, profound hypogammaglobulinemia, and decreased numbers of mature B cells in peripheral blood. We evaluated 5 male Brazilian patients,...

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Bibliographic Details
Main Authors: V.D. Ramalho, E.B. Oliveira Júnior, S.M. Tani, P. Roxo Júnior, M.M.S. Vilela
Format: Article
Language:English
Published: Associação Brasileira de Divulgação Científica 2010-09-01
Series:Brazilian Journal of Medical and Biological Research
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000900015
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Summary:Mutations in Bruton's tyrosine kinase (BTK) gene are responsible for X-linked agammaglobulinemia (XLA), which is characterized by recurrent bacterial infections, profound hypogammaglobulinemia, and decreased numbers of mature B cells in peripheral blood. We evaluated 5 male Brazilian patients, ranging from 3 to 10 years of age, from unrelated families, whose diagnosis was based on recurrent infections, markedly reduced levels of IgM, IgG and IgA, and circulating B cell numbers <2%. BTK gene analysis was carried out using PCR-SSCP followed by sequencing. We detected three novel (Ala347fsX55, I355T, and Thr324fsX24) and two previously reported mutations (Q196X and E441X). Flow cytometry revealed a reduced expression of BTK protein in patients and a mosaic pattern of BTK expression was obtained from mothers, indicating that they were XLA carriers.
ISSN:0100-879X
1414-431X