The tubulin tyrosine ligase like-5 (TTLL5) glutamylates RPGRORF15 in its Glu-Gly–rich repetitive region, which contains motifs homologous to the α-tubulin C-terminal tail; loss of glutamylation has pathological consequences in developing retinal dystrophy [7]. The gene discussed is TTLL5; the disease is inherited retinal dystrophy.