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Åke Lernmark

Principal investigator

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Lymphopenia in the BB rat model of type 1 diabetes is due to a mutation in a novel immune-associated nucleotide (Ian)-related gene.


  • Armand J. MacMurray
  • Daniel H. Moralejo
  • Anne E. Kwitek
  • Elizabeth A. Rutledge
  • Brian Van Yserloo
  • Paul Gohlke
  • Sara J. Speros
  • Ben Snyder
  • Jonathan Schaefer
  • Sabine Bieg
  • Jianjie Jiang
  • Ruth A. Ettinger
  • Jessica Fuller
  • Terri L. Daniels
  • Anna Pettersson
  • Kimberly Orlebeke
  • Bruce Birren
  • Howard J. Jacob
  • Eric S. Lander
  • Åke Lernmark

Summary, in English

The BB (BioBreeding) rat is one of the best models of spontaneous autoimmune diabetes and is used to study non-MHC loci contributing to Type 1 diabetes. Type 1 diabetes in the diabetes-prone BB (BBDP) rat is polygenic, dependent upon mutations at several loci. Iddm1, on chromosome 4, is responsible for a lymphopenia (lyp) phenotype and is essential to diabetes. In this study, we report the positional cloning of the Iddm1/lyp locus. We show that lymphopenia is due to a frameshift deletion in a novel member (Ian5) of the Immune-Associated Nucleotide (IAN)-related gene family, resulting in truncation of a significant portion of the protein. This mutation was absent in 37 other inbred rat strains that are nonlymphopenic and nondiabetic. The IAN gene family, lying within a tight cluster on rat chromosome 4, mouse chromosome 6, and human chromosome 7, is poorly characterized. Some members of the family have been shown to be expressed in mature T cells and switched on during thymic T-cell dev

Publishing year







Genome Research





Document type

Journal article


Cold Spring Harbor Laboratory Press (CSHL)


  • Genetics




  • ISSN: 1549-5469