Simplify the following text for a Grade 10 native English-speaking person.
Original: Diabetes mellitus type 1 ( Type 1 diabetes , IDDM , or , obsoletely , juvenile diabetes ) is a form of diabetes mellitus that results from autoimmune destruction of insulin-producing beta cells of the pancreas .
Simplified: Diabetes mellitus type 1 , also called type 1 diabetes is an autoimmune disease .