Simplify the following text for a Grade 9 native English-speaking person.
Original: Some cases of diabetes are caused by the body 's tissue receptors not responding to insulin ( even when insulin levels are normal , which is what separates it from type 2 diabetes ) ; this form is very uncommon .
Simplified: Diabetes is the condition that results from lack of insulin in a person 's blood , or their body has a problem using the insulin it produces ( Insulin resistance ) . There are other kinds of diabetes , like diabetes insipidus .