Genetic polymorphisms in the thioredoxin 2 (TXN2) gene and risk for spina bifida

Shu Wen, Wei Lu, Huiping Zhu, Wei Yang, Gary M. Shaw, Edward J. Lammer, Ana Islam, Richard H. Finnell

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

TXN2 encodes human thioredoxin 2, a small redox protein important in cellular antioxidant defenses, as well as in the regulation of apoptosis. Txn2 knockout mice fail to complete neural tube closure by E10.5 and die in utero. We hypothesized that genetic variation in human TXN2 gene may alter the function of the encoded protein in a manner associated with an increased risk for neural tube defects (NTDs). A DNA re-sequencing effort of the human TXN2 gene was taken. After a variation in the promoter was identified, the transcriptional activity of different alleles was investigated. The possible association between these variations and the risk of spina bifida was further evaluated in a subset of samples obtained from a large population-based case-control study in California in two different ethnicity groups, non-Hispanic white and Hispanic white. We identified a novel promoter insertion polymorphism located 9 base pairs upstream of the transcription start site of exon 1(-9 insertion). The GA, G and GGGA insertions were associated with a marked decrease of transcriptional activity when overexpressed in both U2-OS (an osteosarcoma cell line) and 293 cells (derived from human embryonic kidney). Further analysis revealed that the GA insertion was associated with increased spina bifida risk for Hispanic whites. Our study revealed a novel Ins/Del polymorphism in the human TXN2 gene proximal promoter region that altered the transcriptional activity and is associated with spina bifida risk. This polymorphism may be a genetic modifier of spina bifida risk in this California population.

Original languageEnglish (US)
Pages (from-to)155-160
Number of pages6
JournalAmerican Journal of Medical Genetics, Part A
Volume149
Issue number2
DOIs
StatePublished - Feb 1 2009

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Keywords

  • Ins/del polymorphism
  • Re-sequencing
  • Spina bifida
  • TXN2
  • Thioredoxin 2

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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