TTC8 and ciliopathy: We used a Bbs8-knock out model since loss of Bbs8 has one of the most pronounced ciliopathy phenotypes particularly with regard to visual dysfunction (Tadenev et al., 2011; Dilan et al., 2018; May-Simera et al., 2018; Kretschmer et al., 2019; Patnaik et al., 2019).