title: Mutation in the TCRα subunit constant gene (TRAC) leads to a human immunodeficiency disorder characterized by a lack of TCRαβ+ T cells.
abstract: Inherited immunodeficiency disorders can be caused by mutations in any one of a large number of genes involved in the function of immune cells. Here, we describe two families with an autosomal recessive inherited immunodeficiency disorder characterized by increased susceptibility to infection and autoimmunity. Genetic linkage studies mapped the disorder to chromosomal region 14q11.2, and a homozygous guanine-to-adenine substitution was identified at the last base of exon 3 immediately following the translational termination codon in the TCRα subunit constant gene (TRAC). RT-PCR analysis in the two affected individuals revealed impaired splicing of the mRNA, as exon 3 was lost from the TRAC transcript. The mutant TCRα chain protein was predicted to lack part of the connecting peptide domain and all of the transmembrane and cytoplasmic domains, which have a critical role in the regulation of the assembly and/or intracellular transport of TCR complexes. We found that T cells from affected individuals were profoundly impaired for surface expression of the TCRαβ complex. We believe this to be the first report of a disease-causing human TRAC mutation. Although the absence of TCRαβ+ T cells in the affected individuals was associated with immune dysregulation and autoimmunity, they had a surprising level of protection against infection.
authors.affiliation: Wellchild Paediatric Research Centre, Department of Medical and Molecular Genetics, University of Birmingham School of Medicine, Birmingham, United Kingdom.
authors.forename: Neil V
authors.initials: NV
authors.lastname: Morgan
authors.forename: Sarah
authors.initials: S
authors.lastname: Goddard
authors.forename: Tony S
authors.initials: TS
authors.lastname: Cardno
authors.forename: David
authors.initials: D
authors.lastname: McDonald
authors.forename: Fatimah
authors.initials: F
authors.lastname: Rahman
authors.forename: Dawn
authors.initials: D
authors.lastname: Barge
authors.forename: Andrew
authors.initials: A
authors.lastname: Ciupek
authors.forename: Anna
authors.initials: A
authors.lastname: Straatman-Iwanowska
authors.forename: Shanaz
authors.initials: S
authors.lastname: Pasha
authors.forename: Mary
authors.initials: M
authors.lastname: Guckian
authors.forename: Graham
authors.initials: G
authors.lastname: Anderson
authors.forename: Aarnoud
authors.initials: A
authors.lastname: Huissoon
authors.forename: Andrew
authors.initials: A
authors.lastname: Cant
authors.forename: Warren P
authors.initials: WP
authors.lastname: Tate
authors.forename: Sophie
authors.initials: S
authors.lastname: Hambleton
authors.forename: Eamonn R
authors.initials: ER
authors.lastname: Maher
mesh_terms: D001483:Base Sequence; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D006367:HeLa Cells; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics* / Q000276:immunology*; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta