KDELR2 and osteogenesis imperfecta: As an example of IMPC data supporting disease gene discovery, the role of biallelic variants in KDELR2 causing a form of osteogenesis imperfecta with neurodevelopmental features was supported by incompletely penetrant preweaning lethality, bone structural abnormalities in early adult mice, and decreased size, abnormalities in head shape and size, facial dysmorphology, and abnormal embryonic body wall structure reported in the embryo in the IMPC mutant (Efthymiou et al., 2021).