COL4A5 and Hearing impairment: Wang et al. (2018) suggested that the two dislocation mutations in COL4A5 and COL4A6 could be risk factors for cerebrovascular fibromuscular dysplasia. The dislocation mutation of the COL4A6 gene causes serious non-syndromic hearing impairment in males (Rost et al., 2014). Downregulation of COL4A6 may promote prostate cancer progression and invasion (Ma et al., 2020).