Частый или не частый, но наследственность может быть одной из причин.The exact cause of type 1 diabetes is unknown. Usually, the body's own immune system — which normally fights harmful bacteria and viruses — mistakenly destroys the insulin-producing (islet, or islets of Langerhans) cells in the pancreas. Other possible causes include:GeneticsExposure to viruses and other environmental factorshttps://www.mayoclinic.org/diseases-conditions/type-1-diabetes/symptoms-causes/syc-20353011