Expression of beta-cell autoimmunity does not differ between potential dizygotic twins and siblings of patients with type 1 diabetes

J Autoimmun. 2004 Nov;23(3):275-9. doi: 10.1016/j.jaut.2004.07.001.


Twin studies help to elucidate the contribution of genes and environment to type 1 diabetes (T1DM). The Diabetes Prevention Trial-1 (DPT-1) tested for anti-islet autoantibodies: 34,765 non-diabetic non-twin siblings of patients with T1DM, and 896 non-diabetic potential twins of patients with T1DM. Zygosity (being monozygotic [MZ] or dizygotic [DZ]) was unknown except for 357 non-diabetic subjects with opposite gender to their diabetic twin, who must be DZ. Expression of cytoplasmic islet cell (ICA), GAD65, ICA512 and insulin autoantibodies in 357 different-sex (DZ) potential non-diabetic twins of T1DM patients was, respectively, 4.5%, 4.7%, 3.0% and 2.4%, which was lower than in 539 same-sex potential non-diabetic twins (including MZ and DZ) of T1DM patients for ICA (7.8%, p < 0.05), GAD65 (13.4%, p < 0.0001) and ICA512 (6.5%, p < 0.03). In contrast, expression of ICA, GAD65, ICA512 and insulin autoantibodies was not significantly different in different-sex (DZ) potential twins versus all siblings (respectively, 4.2%, 4.8%, 2.2%, 2.5%), different-sex siblings (3.9%, 4.9%, 2.2%, 2.5%) or same-sex siblings (4.4%, 4.7%, 2.2%, 2.5%) of T1DM patients. In conclusion, anti-islet autoimmunity is not increased in non-diabetic DZ twins of T1DM patients compared to non-diabetic siblings of T1DM patients, suggesting that the greater environmental sharing by twins does not increase risk of anti-islet autoimmunity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Autoimmunity / immunology*
  • Diabetes Mellitus, Type 1 / immunology*
  • Diabetes Mellitus, Type 1 / pathology
  • Female
  • Humans
  • Islets of Langerhans / immunology*
  • Islets of Langerhans / pathology
  • Male
  • Pedigree
  • Siblings*
  • Twins, Dizygotic / immunology*