Pathogenic variants in NEK9 were identified in the fetus with lethal congenital contracture syndrome 10 (OMIM: 617022) and in children with arthrogryposis, Perthes disease, and upward gaze palsy (APUG and OMIM: 614262). This evidence concerns the gene NEK9 and arthrogryposis, Perthes disease, and upward gaze palsy.