title: Antibodies to glutamic acid decarboxylase in Australian children with insulin-dependent diabetes mellitus and their first-degree relatives.
abstract: Antibodies to glutamic acid decarboxylase (GAD), previously known as the 64-kD pancreatic islet cell autoantigen, are an important serologic marker of insulin-dependent diabetes mellitus (IDDM). Antibodies to GAD (anti-GAD) were examined in sera from Australian children with newly diagnosed IDDM (within 1 mo of diagnosis), IDDM of longer duration (mean +/- SD, 4.8 +/- 3.3 y), and in first-degree relatives, using a radioimmuno-precipitation assay with purified porcine brain GAD as antigen. Antibodies to islet cell cytoplasmic antigens (ICAb) were tested concurrently. The frequency of anti-GAD was not significantly different in children with newly diagnosed IDDM (31 of 42, 74%) and with IDDM of longer duration (14 of 21, 67%), whereas ICAb were present more frequently in children with newly diagnosed IDDM (64%) than in those with longer duration IDDM (14%). In all, 90% of children with newly diagnosed IDDM had either anti-GAD or ICAb, whereas only 48% had both. For the 77 first-degree relatives, the frequency of anti-GAD was 2% (one of 44) in parents and 6% (two of 33) in siblings; ICAb were not detected in any of these relatives. The presence of anti-GAD in the majority of children with IDDM, irrespective of the duration of their disease, represents a useful diagnostic marker for IDDM, and should be of value in ascertaining individuals at risk for developing IDDM.
authors.affiliation: Centre for Molecular Biology and Medicine, Monash University, Victoria, Australia.
authors.forename: Q Y
authors.initials: QY
authors.lastname: Chen
authors.forename: M J
authors.initials: MJ
authors.lastname: Rowley
authors.forename: G C
authors.initials: GC
authors.lastname: Byrne
authors.forename: T W
authors.initials: TW
authors.lastname: Jones
authors.forename: T
authors.initials: T
authors.lastname: Tuomi
authors.forename: W J
authors.initials: WJ
authors.lastname: Knowles
authors.forename: P Z
authors.initials: PZ
authors.lastname: Zimmet
authors.forename: I R
authors.initials: IR
authors.lastname: Mackay
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001315:Australia; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000201:enzymology* / Q000235:genetics / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006683:HLA-DQ Antigens / Q000235:genetics; D059866:HLA-DQ beta-Chains; D006801:Humans; D007515:Islets of Langerhans / Q000201:enzymology / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015531:Radioimmunoprecipitation Assay
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; C075362:islet 64k antigen; D005968:Glutamate Decarboxylase