COL1A1 and type 1 diabetes mellitus: Expression of Fbn1, Col1a1 and Col3a1 is reduced by type 1 diabetes in skeletal muscle [39], expression of these three genes as well as Col5a3, Col5a1 and Sparc is reduced by type 1 diabetes in corpus cavernosum [35], Sparc expression is reduced in type 1 diabetic kidneys [63], and Fbn1 and Col3a1 expression is reduced in type 1 diabetic heart muscle [38].