Involved in hearing and vision as member of the USH2 complex (PubMed:20502675). Necessary for elongation and maintenance of inner and outer hair cell stereocilia in the organ of Corti in the inner ear (PubMed:15590699). Involved in the maintenance of the hair bundle ankle region, which connects stereocilia in cochlear hair cells of the inner ear (PubMed:20502675, PubMed:24334608). In retina photoreceptors, required for the maintenance of periciliary membrane complex that seems to play a role in regulating intracellular protein transport (PubMed:20502675). Forms homooligomers (PubMed:15590698, PubMed:25406310). Interacts (via C-terminal PDZ domain) with MYO15A; this interaction is necessary for localization of WHRN to stereocilia tips (PubMed:15654330, PubMed:15590698). Interacts (via C-terminal PDZ domain) with MPP1/p55 (PubMed:16829577, PubMed:17584769). Interacts with LRRC4C/NGL1 (PubMed:15590698). Interacts with MYO7A (PubMed:15590698). Interacts with RPGR (PubMed:22323458). Interacts with EPS8 (PubMed:21236676). Interacts with CASK. Interacts with CIB2 (By similarity). Component of USH2 complex, composed of ADGRV1, PDZD7, USH2A and WHRN (PubMed:20502675, PubMed:25406310). Interacts (via PDZ domains) with PDZD7; the interaction is direct (PubMed:25406310). Interacts (via N-terminal PDZ domain) with USH2A (via cytoplasmic region) (PubMed:16301217, PubMed:20502675, PubMed:23055499). Interacts with ADGRV1/MASS1 (via cytoplasmic region) (PubMed:20502675, PubMed:23055499). Detected at the level of stereocilia in inner and outer hair cells of the cochlea and vestibule. Localizes to both tip and ankle-link stereocilia regions. Colocalizes with the growing ends of actin filaments (PubMed:15590699, PubMed:15590698, PubMed:15654330, PubMed:24334608). Colocalizes with MPP1 in the retina, at the outer limiting membrane (OLM), outer plexifirm layer (OPL), basal bodies and at the connecting cilium (CC) (PubMed:17584769). In photoreceptors, localizes at a plasma membrane microdomain in the apical inner segment that surrounds the connecting cilia called periciliary membrane complex (PubMed:20502675, PubMed:24334608). Expressed in the retina. Colocalizes with RPGR in the photoreceptor connecting cilium, a thin bridge linking the cell body and the light-sensing outer segment (at protein level). Detected in the inner ear throughout development from embryonic day 12 to 20 days after birth. Displays a dynamic pattern of expression after birth, demonstrating an ordered appearance and fade-out across stereocilia rows. Isoforms 5, 6, 7 and 8 are not detected in the retina (PubMed:20502675). At 10.5 dpc, expressed in the basal plate of the spinal cord, in the ventralneural epithelium of the developing brain and in the region of the lung bud. At 12.5 dpc, expressed in the complete neuroepithelium except for the neocortex. In the developing eye, expressed in the inner neuroblastic layer. At 14.5 dpc, detected in the intervertebral cartilage, the cortex of the developing kidney, the tongue, the region of the urethra and strongly in specific regions of the brain, e.g. striatum, optic recess, ventral tegmental area, roof of the midbrain, choroid plexus of the lateral ventricles and the fourth ventricle. The developing neocortex is devoid of expression. At this timepoint, expression is first notable in the inner ear in the developing maculae of the saccule and the utricle, in the cristae of the semicircular canals and in the vestibulocochlear ganglion. In the developing neural retina, a strong signal is present in the inner neuroblastic layer. At 16.5 dpc, expression is very similar to that at 14.5 dpc. At 18.5 dpc, expression is mainly as in 16.5 dpc. Expression in the ganglion layers of the retina decreases and is no longer detected in the innermost region of these layers. From postnatal day 7 (P7) onwards, also the developing photoreceptor cells express whirlin (PubMed:16434480). Expression decreases by 11 days after birth in inner ear hair cells and by 14 days after birth in outer ear hair cells. Expressed in vestibular hair cells at high levels through to adulthood. Defects in Whrn are the cause of the phenotype whirler (wi). Mutants are characterized by deafness due to malformation of the cochlear inner and outer hair cells and by circling behavior. Stereocilia are shorter and wider than in wild-type animals and there is a decrease in the number of actin filaments in inner and outer hair cells. The number of outer hair cell stereocilia is reduced with increased spacing between them. Mutant mice for isoform 1 appear viable and comparable to their wild-type littermates in growth characteristics, reproductive performance and general health (PubMed:20502675). At 2 and 9 months of age, knockouts show a profound hearing loss across all cochlear frequencies (PubMed:20502675). At 28 to 33 months, they show signs for retinal degeneration such as a thinner photoreceptor nuclear layer and outer segments shortened (PubMed:20502675). Major isoform. May be due to intron retention. May be due to intron retention.