COL4A1 and cerebrovascular disorder: Cerebrovascular disease is a particularly devastating consequence of COL4A1 mutations, and we have previously demonstrated that ICH severity in Col4a1+/Δex41 mice increases with age and is exacerbated by environmental factors, such as birth trauma, exercise and anticoagulants (Gould et al., 2006; Jeanne et al., 2015).