What causes Type 1 Diabetes?

So, people have been doing research for years with regards to type 1 diabetes, and we understand that there are specific antibodies that would attack the beta cells which produce insulin within the body. The common antibodies that we are aware of are GAD antibodies or islet cell antibodies. We also have the zinc transporter antibodies and there are eight antibodies and these antibodies attack the beta cells within a patient's own body and stop its ability to produce insulin. 95% of the patients who would have these antibodies would have a full-blown manifestation of type 1 diabetes. But we also have patients, 5% of the group of the type 1 diabetes patients in which we don't know the cause for it, and maybe they have antibodies that we are not measuring and the cause remains unknown.