Required for normal development of intervertebral disks. Interacts with CPNE4 (via VWFA domain) (PubMed:12522145). Expressed predominantly in the notochord and mesonephros during embryogenesis as well as in other areas such as the epithalamus sulcus, lens vesicle, inner retinal layer, heart, hepatic primordial surface, infundibulum, surface ectoderm, hind gut and limb bud mesenchyme. In adults, expressed in a range of tissues including the nucleus pulposus, corpus callosum, kidney, cardiac muscle, Sertoli cells and hair follicles. Mice display a kinky-tail phenotype in about half of homozygotes with defects in the nucleus pulposus and annulus fibrosus of intertebral disks. Shortening and curving of caudal vertebrae 20-25 is apparent by the age of 2 weeks.