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Distribution of autoantibodies to glutamic acid decarboxylase across the spectrum of diabetes mellitus seen in South Africa
Author(s) -
Panz V. R.,
Kalk W. J.,
Zouvanis M.,
Joffe B. I.
Publication year - 2000
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1046/j.1464-5491.2000.00324.x
Subject(s) - medicine , body mass index , type 2 diabetes mellitus , endocrinology , glutamate decarboxylase , diabetes mellitus , autoantibody , type 1 diabetes , gastroenterology , antibody , immunology , biology , enzyme , biochemistry
SUMMARYAims This study investigated the association between glutamic acid decarb‐ oxylase antibodies (GAD‐AB) and Type 1, Type 2, pancreatic and lipoatrophic diabetes mellitus (DM) in South African patients. Methods Four groups were selected: group A, 100 Black Type 1 DM patients (age at onset < 35 years, body mass index (BMI) < 27 kg/m 2 and insulin dependent within 1 year of presentation); group B, 80 Black Type 2 DM patients (age at onset > 35 years, BMI > 27 kg/m 2 and controlled on oral hypoglycaemic agents for at least 1 year after presentation); group C, 10 patients of varying ethnicity with DM or impaired glucose tolerance secondary to chronic pancreatitis; group D, five patients of varying ethnicity with DM associated with total lipodystrophy. Fifty healthy Black control subjects were also studied (group E). Serum GAD‐AB and random C‐peptide levels were measured by radioimmunoassay. Results Mean C‐peptide concentration was significantly lower in Type 1 DM patients than Type 2 DM patients ( P < 0.00001). Forty‐four patients with Type 1 DM were GAD‐AB‐positive compared to two patients with Type 2 DM. Two control subjects were also GAD‐AB‐positive. No patient in the other groups had a titre > 1 U/ml. Type 1 DM patients who were GAD‐AB‐positive did not differ from those who were GAD‐AB‐negative for age at onset, duration of DM or C‐peptide concentrations. Conclusions Auto‐immune beta‐cell destruction has an important role in the pathogenesis of Type 1 DM amongst African patients. However, Type 2 African DM patients and other diabetes subtypes are largely GAD‐AB‐negative.