A hypermorphic IkappaBalpha mutation is associated with autosomal dominant anhidrotic ectodermal dysplasia and T cell immunodeficiency

J Clin Invest. 2003 Oct;112(7):1108-15. doi: 10.1172/JCI18714.

Abstract

X-linked anhidrotic ectodermal dysplasia with immunodeficiency (XL-EDA-ID) is caused by hypomorphic mutations in the gene encoding NEMO/IKKgamma, the regulatory subunit of the IkappaB kinase (IKK) complex. IKK normally phosphorylates the IkappaB-inhibitors of NF-kappaB at specific serine residues, thereby promoting their ubiquitination and degradation by the proteasome. This allows NF-kappaB complexes to translocate into the nucleus where they activate their target genes. Here, we describe an autosomal-dominant (AD) form of EDA-ID associated with a heterozygous missense mutation at serine 32 of IkappaBalpha. This mutation is gain-of-function, as it enhances the inhibitory capacity of IkappaBalpha by preventing its phosphorylation and degradation, and results in impaired NF-kappaB activation. The developmental, immunologic, and infectious phenotypes associated with hypomorphic NEMO and hypermorphic IKBA mutations largely overlap and include EDA, impaired cellular responses to ligands of TIR (TLR-ligands, IL-1beta, and IL-18), and TNFR (TNF-alpha, LTalpha1/beta2, and CD154) superfamily members and severe bacterial diseases. However, AD-EDA-ID but not XL-EDA-ID is associated with a severe and unique T cell immunodeficiency. Despite a marked blood lymphocytosis, there are no detectable memory T cells in vivo, and naive T cells do not respond to CD3-TCR activation in vitro. Our report highlights both the diversity of genotypes associated with EDA-ID and the diversity of immunologic phenotypes associated with mutations in different components of the NF-kappaB signaling pathway.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Ectodermal Dysplasia / genetics*
  • Humans
  • I-kappa B Kinase
  • I-kappa B Proteins / genetics*
  • Immunologic Deficiency Syndromes / genetics*
  • Male
  • Mutation*
  • NF-kappa B / physiology*
  • Protein-Serine-Threonine Kinases / genetics*
  • Receptor-CD3 Complex, Antigen, T-Cell / physiology
  • Signal Transduction / physiology
  • T-Lymphocytes / immunology*
  • Transcription, Genetic
  • Tumor Necrosis Factor-alpha / physiology

Substances

  • I kappa B beta protein
  • I-kappa B Proteins
  • NF-kappa B
  • Receptor-CD3 Complex, Antigen, T-Cell
  • Tumor Necrosis Factor-alpha
  • Protein-Serine-Threonine Kinases
  • CHUK protein, human
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human