Bi-allelic mutations in the Roundabout homolog of Drosophila 3 (ROBO3) gene cause horizontal gaze palsy with progressive scoliosis (HGPPS; OMIM 607313), a rare autosomal recessive disorder with oculomotor and general disturbances in innervation [1,2]. Here, ROBO3 is linked to horizontal gaze palsy with progressive scoliosis.