Prevalence and Phenotypic Correlations of GAD 65 and Z n T 8 Autoantibodies in Young‐Onset Diabetes: A Pilot Study in a Tertiary Centre in Bangladesh

INTRODUCTION: The increasing prevalence of young-onset diabetes in Bangladesh presents a diagnostic challenge due to overlapping clinical phenotypes. Data regarding glutamic acid decarboxylase (GAD65) and, especially, Zinc Transporter 8 (ZnT8) antibodies in the Bangladeshi population remain scarce. OBJECTIVE: To determine the frequency of GAD65 and ZnT8 autoantibodies in young Bangladeshi individuals with diabetes (aged < 30 years) compared with normal glucose tolerance (NGT) controls and to evaluate the correlation between antibody titres and phenotypic variables. MATERIALS AND METHODS: ; mean ± SD) at a tertiary care hospital in Dhaka. Clinical and biochemical data were recorded, and serum GAD65 and ZnT8 antibodies were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: GAD65 antibody was positive in 21.7% (10/46) of the DM group compared to 11.9% (5/42) of the NGT group (p = 0.265). ZnT8 antibody positivity was 4.3% (2/46) in the DM group and absent in controls (p = 0.495). All ZnT8 antibody-positive individuals were also positive for GAD65 antibody. Within the DM group, no statistically significant differences were detected in phenotypic variables (presenting symptoms, age, family history of DM, BMI, waist circumference, blood pressure, and blood glucose) between participants who were seropositive for any islet autoantibody and those who were seronegative for both (p = ns for all). A positive correlation was observed between antibody titres and HbA1c% in the DM group (r = 0.404, p = 0.005 for GAD65; r = 0.517, p < 0.001 for ZnT8). CONCLUSION: In this pilot cohort, GAD65 positivity was more frequent than ZnT8 positivity among young Bangladeshi individuals with diabetes, while GAD65 positivity was also detected in a proportion of NGT controls. No clear phenotypic differences were identified between antibody-positive and antibody-negative diabetes cases, although antibody titres showed positive correlations with HbA1c.