COL1A1 and Ehlers-Danlos syndrome: Jrt mice have a dominant mutation in Col1a1 causing skipping of exon 9 and leading to an 18 amino acid deletion in the N-terminal domain of Col1a1. Mice exhibit reduced bone mass and brittle bones susceptible to fractures as OI characteristics, and reduced skin tensile properties and spine curvature as part of EDS phenotype [24].