While antigens (See: Antigen) induce the immune system to produce antibodies, autoantigens are a result of mutations. Autoantigens are responsible for stimulating autoantibodies (See: Autoantibodies), thereby causing autoimmune diseases. Many identified autoantigens are responsible for autoimmunity and autoimmune diseases. In the case of type 1 diabetes, beta cell autoantigens and the activation of autoreactive lymphocytes against them is the leading cause for the failure of the pancreas to produce of insulin. Most autoantibodies and autoantigens are identified in people with type 1 diabetes in their early childhood around the ages of one and three and then they peak around their puberty.