title: Clinical and genetic characteristics of GAD-antibody positive patients initially diagnosed as having type 2 diabetes.
abstract: The present study was conducted to clarify the clinical and genetic characteristics of the diabetic patients who have antibodies to glutamic acid decarboxylase (GADab) but are diagnosed initially as type 2 diabetes because of the slow progression. Fifty-five GADab+ patients and 137 GADab- patients were recruited. The GADab+ patients were divided into two subgroups according to their antibody titers. The high-titer subgroup (Ab > or = 20 U/ml) had lower urinary C-peptide concentrations, and was assigned insulin therapy more often than the GADab- patients. In contrast to the high-titer subgroup, clinical parameters in the low-titer subgroup were similar to the GADab- diabetic patients. The urinary C-peptide levels correlated negatively with the GADab titer in the GADab+ patients. Analysis of type 1 diabetes-susceptible HLA alleles revealed high frequencies of the B54 and DRB1*0405 allele, but not the B61 and DRB1*0901 alleles, in the high-titer subgroup, whereas the frequency of the protective DRB1*1502 allele was decreased. The GADab+ patients with the B54 allele had higher GADab titers and lower urinary C-peptide excretion than patients without this allele. These data indicated that patients with a high-GADab titer share the autoimmune background characteristic of type 1 diabetes.
authors.affiliation: Department of Internal Medicine I, Faculty of Medicine, Oita Medical University, 1-1, Idaigaoka, Hasama, Oita 879-5593, Japan. khamaguc@med.oita-u.ac.jp
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hamaguchi
authors.forename: Akinori
authors.initials: A
authors.lastname: Kimura
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Kusuda
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yamashita
authors.forename: Michio
authors.initials: M
authors.lastname: Yasunami
authors.forename: Megumi
authors.initials: M
authors.lastname: Takahasi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Abe
authors.forename: Hironobu
authors.initials: H
authors.lastname: Yoshimatsu
mesh_terms: D000328:Adult; D000483:Alleles; D001323:Autoantibodies / Q000097:blood*; D015551:Autoimmunity / Q000235:genetics; D002096:C-Peptide / Q000652:urine; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000235:genetics / Q000503:physiopathology* / Q000652:urine; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D002096:C-Peptide; D006680:HLA Antigens; D005968:Glutamate Decarboxylase