ATP4B and type 1 diabetes mellitus: Analysis of ATP4B autoantibodies revealed that five of the high risk children samples were seropositive including one child who was negative for islet autoantibodies and did not develop T1D, one child who was positive for islet cell autoantibodies and also did not develop T1D and three T1D children (3/24; 15%) who were also co-positive for islet cell autoantibodies (Figure 4A).