Association of Zinc Transporter-8 Autoantibody (ZnT8A) with Type 1 Diabetes Mellitus

Zinc transporter 8 autoantibody (ZnT8A), discovered through bioinformatics, is identified as another major biomarker for type 1 diabetes mellitus (T1DM), expanding the panel of diagnostic autoantibodies. The absence of standard autoantibodies in T1DM patients and the presence of ZnT8A in individuals before disease development has led the researchers to evaluate ZnT8A to gather information about the frequency and its association. Therefore, we aim to find out the concentration of ZnT8A and its association with T1DM. A case-control study with 25 type 1 diabetes mellitus patients and 25 first-degree relatives of cases as controls was conducted at Ziauddin University in collaboration with the Baqai Institute of Diabetology and Endocrinology (BIDE), Karachi. Demographic data were collected from patients on a standard questionnaire. Blood samples were collected, after approval from Ziauddin Ethics Review Committee, from subjects and serum was separated to estimate ZnT8A by using sandwich enzyme-linked immunosorbent assay (ELISA). The mean age at diagnosis of T1DM patients was 13.40±5.05 years, and the duration of diabetes was 7.74±5.85 years. The frequency of ZnT8A was found higher in cases (19 (76%)) compared to controls (6 (24%)). ZnT8A concentrations were significantly higher in cases (13.82 ng/ml) compared to the controls (8.78 ng/ml; p= 0.024). The cut-off value of 9 ng/ml was selected for measuring sensitivity, specificity, and accuracy, which were determined as 76%, 76%, and 76%, respectively. ZnT8A was found significantly associated with T1DM. Subjects with ZnT8A values ≥ 9 ng/ml are 10 times more at risk to develop T1DM (p = 0.000).