SSPOP and idiopathic scoliosis: Recently, a series of studies using zebrafish showed that a mutation in the SCO-spondin gene (sspo) causes a phenotype with an abnormal ventral curvature of the body axis and idiopathic scoliosis (Cantaut-Belarif et al., 2018; Lu et al., 2020; Rose et al., 2020).