Importantly, both monogenic and sporadic forms of COL4A-related SVD are likely to share similar pathological mechanisms, as rare coding variants in COL4A1/A2 also occur in sporadic form of ICH, while common COL4A1/A2 non-coding variants have been identified as risk factor for sporadic lacunar stroke (Chung et al., 2019; Persyn et al., 2020; Traylor et al., 2021), sporadic ICH (Malik et al., 2018; Rannikmäe et al., 2015), and white matter hyperintensities (Persyn et al., 2020) in the general population. This evidence concerns the gene COL4A1 and snowflake vitreoretinal degeneration.