ANTIBODIES TO GLUTAMIC-ACID DECARBOXYLASE IN YOUNG CHINESE DIABETIC-PATIENTS

Antibodies to glutamic acid decarboxylase (GAD) are a useful autoimmun e marker for type I diabetes mellitus in Caucasians. We examined antib odies to GAD and their relationships with clinical features and pancre atic beta cell function in 140 young Chinese diabetic patients. Over a n 18-month period beginning in 1995, 140 young Chinese diabetic subjec ts with age of onset of disease less than or equal to 35 years and age <40 years were recruited consecutively, irrespective of their modes o f presentation. Clinical features, antibodies to GAD and pancreatic be ta cell function (using a glucagon stimulation test) were examined. In creased levels of antibodies to GAD (>18 units) were detected in 12.1% (n = 17) of these subjects. Forty-three (31%) patients had a classica l type 1 presentation and 65 (46%) patients were insulin-deficient bas ed on post-glucagon plasma C-peptide levels. Patients who were insulin -deficient and had a type 1 presentation had the highest prevalence of antibodies to GAD (29.0%) compared with patients who had a type 2 pre sentation and were non-insulin deficient (6.4%, P = 0.003). Patients w ho had antibodies to GAD had lower body mass index and waist-hip ratio , earlier onset of disease, lower blood pressure, plasma triglyceride and C-peptide, and higher concentrations of plasma high-density lipopr otein cholesterol and glycated haemoglobin; and were more likely to re quire drug treatment, compared with those without antibodies to GAD. I n conclusion, there was a low prevalence of antibodies to GAD in Chine se young diabetic patients although such antibodies remained a relativ ely specific marker for insulin deficiency and acute presentation. Cau ses other than autoimmunity should be sought to explain the high preva lence of insulin deficiency in these young Chinese patients.