Analysis of the PAX8 gene in 32 children with thyroid dysgenesis and functional characterization of a promoter variant

Denise Perone*, Geraldo Medeiros-Neto, Célia Regina Nogueira, Antonio José Chagas, Vera Maria Alves Dias, Maria Fátima Viana, Peter Andreas Kopp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Background: The molecular basis underlying the development of thyroid dysgenesis remains largely unknown. The objective of this study was to analyze the PAX8 gene in 32 children with congenital hypothyroidism due to thyroid dysgenesis for mutations, and to characterize the functional consequences of the mutations. Methods: The 5′-untranslated region and the entire coding region of the PAX8 gene were analyzed in 32 children. Functional analyses with a reporter gene assay were performed in transfected PCCL3 and TSA cells. Results: Thirty children did not have any sequence alterations. Two individuals had a previously identified monoallelic cytosine to thymine transition at position -983 in the promoter (-983C>T; mutant P. A of the ATG of the initiator codon is designated as +1), and a novel guanine to cytosine transversion in the non-coding exon 1 (-465G>C; mutant E). Functional analysis revealed that the basal transcriptional activity of the mutants is decreased compared to the wild type. Gel mobility shift assays indicated that mutant P does not interact with a transacting factor whose nature remains to be elucidated. The DNA binding property of mutant E were similar compared to the wild type. Conclusions: These results suggest that mutations in PAX8 are most likely a very rare cause of thyroid dysgenesis. The observed sequence alterations result in diminished transcriptional activity and, in conjunction with other genetic and non-genetic modifiers, they may contribute to the pathogenesis of thyroid hypoplasia and hypothyroidism.

Original languageEnglish (US)
Pages (from-to)193-201
Number of pages9
JournalJournal of Pediatric Endocrinology and Metabolism
Volume29
Issue number2
DOIs
StatePublished - Feb 1 2016

Keywords

  • PAX8 gene
  • congenital hypothyroidism
  • mutation
  • promoter
  • thyroid dysgenesis
  • transcription factor

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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