TABLE 4

Combinations of islet autoantibody epitopes and risk for type 1 diabetes

GAD antibodies
IA-2 antibodies
Epitope combination*
n (type 1 diabetes cases)10-year riskEpitope combination*
n (type 1 diabetes cases)10-year risk
MIDCOOHNH267IA-2βPTPJM
++++24 (8)39%+++13 (8)81%
+++12 (6)26%++12 (10)100%§
+++15 (5)56%++1 (1)
++62 (21)45%+4 (3)
++1 (0)++8 (3)34%
+13 (3)27%+10 (4)44%
+++1 (0)+9 (2)41%
+5 (2)48%
+6 (1)20%
10 (3)33%4 (1)
  • *

    * For GAD antibodies, MID refers to epitopes within GAD65 amino acids 235–442, COOH refers to epitopes within GAD65 amino acids 436–585, NH2 refers to epitopes within GAD65 amino acids 1–100, and GAD67 refers to epitopes found in GAD67. For IA-2 antibodies, IA-2β refers to epitopes found in the PTP region of IA-2β and IA-2, PTP refers to epitopes found in the PTP region of IA-2 and not IA-2β, and JM refers to epitopes within the IA-2 juxtamembrane region amino acids 601–682 (combinations with no relatives are not shown).

  • n refers to the number of relatives positive for that epitope combination;

  • risk of diabetes calculated using life-table analysis (risks are not shown for cells containing less than five relatives);

  • §

    § P = 0.009 vs. PTP and/or JM-positive/IA-2β–negative groups, log rank test.