The affected amino acids identified in this study are moderately or highly conserved in evolution (Figure 1C), and both affect the N-terminal WD40 domain (Figure S1). The third mutation alters the splice site of exon 7 and results in a truncation of the protein within the last WD40 repeat. This WD40 domain, but not the C-terminal region of POC1, has been demonstrated to be sufficient for targeting POC1 localization to centrioles.32 Indeed, whereas wild-type POC1B localized to the basal bodies, as previously reported, both p.Gln67del and p.Arg106Pro variant POC1B revealed a loss of association with the basal body of the cilium (Figure 3). The effect of the variants on Poc1b in zebrafish was addressed by coinjection of a poc1b MO in combination with human POC1B mRNA carrying either one of the mutations. In contrast with coinjection of wild-type mRNA, coinjection of the mutated mRNA could not induce (partial) rescue of the ocular phenotype, confirming the disturbing retinal effect of the variant amino acid residues (Figure 4B).