Acts upstream of or within several processes, including flagellated sperm motility; photoreceptor cell maintenance; and photoreceptor cell outer segment organization. Located in several cellular components, including ciliary base; photoreceptor distal connecting cilium; and ribbon synapse. Used to study nephronophthisis 4. Human ortholog(s) of this gene implicated in Joubert syndrome 4; Senior-Loken syndrome; congenital heart disease; nephronophthisis; and nephronophthisis 4. Orthologous to human NPHP4 (nephrocystin 4). [provided by Alliance of Genome Resources, Apr 2022]