Background Zinc transporter 8 autoantibodies (ZnT8Abs) together with glutamic acid decarboxylase autoantibodies (GADAbs), insulinoma antigen 2 autoantibodies (IA-2Abs) and insulin autoantibodies (IAbs) are markers of type 1 diabetes mellitus (T1DM). We studied the prevalence of ZnT8Ab in children with autoimmune thyroid diseases (AITDs) to assess the association of AITDs and T1DM at the serological level. Methods The study groups consisted of 44 children with Graves' disease (GD), 65 children with Hashimoto's thyroiditis (HT), 199 children with T1DM with or without AITDs and 58 control children. ZnT8Ab, GADAb, IA-2Ab, IAb, 21-hydroxylase autoantibodies (21-OHAbs) and acetylcholine receptor autoantibodies (AChRAbs) were measured. Results ZnT8Abs were found in 4/44 (9.1%) patients with GD, and 4/44 (9.1%) patients with GD were positive for GADAb. Of the 65 HT patients, six (9.2%) were positive for ZnT8Ab, while four (6.2%) were positive for GADAb. In the T1DM group, 128/199 (64%) of the patients were positive for ZnT8Ab, 133/199 (67%) for GADAb and 109/199 (55%) for IA-2Ab. One GD patient and one HT patient were positive for all the four diabetes-associated autoantibodies. Two HT patients were positive for three diabetes autoantibodies. Two GD (4.5%) and five HT (7.7%) patients were positive for 21-OHAb only. None of the patients had AChRAb. In the control group, 2/58 (3.4%) were positive for GADAb and 2/58 (3.4%) were positive for ZnT8Ab. Conclusions Diabetes-associated autoantibodies including ZnT8Ab were found in children and adolescents with GD and HT.
Keywords: Graves’ disease; Hashimoto’s thyroiditis; autoantibodies; autoimmune thyroid disease (AITD); type 1 diabetes mellitus; zinc transporter 8 autoantibodies (ZnT8Ab).