TTC8 and Bardet-Biedl syndrome: We focused on the alternative isoform usage of the Ttc8 gene in part because mutations in Ttc8 have been implicated in various ciliopathies including non-syndromic retinitis pigmentosa (RP) [39, 40] and in Bardet-Biedl syndrome (BBS, which commonly includes RP among its symptoms) [41, 42].