Despite a very recent report on a naturally occurring Wnt1 mutation of valine to phenylalanine at position V337 (V335), causing osteogenesis imperfecta through impaired Wnt signaling [24], the identification of the residue V377 as being essential for Wnt3a activity during zebrafish embryogenesis is novel. Here, WNT3A is linked to osteogenesis imperfecta.