While it remains possible that additional sequence variants in non-JBTS genes also contributed to the enhanced phenotype in individual UW48-3 and while our findings from a large human cohort remain of anecdotal nature given the rarity of this highly heterogeneous genetic disorder, taken together with the zebrafish experiments, they suggest that NINL may act as a genetic modifier specifically for CC2D2A-caused Joubert syndrome. This evidence concerns the gene NINL and Joubert syndrome.