A study of one pedigree indicated that a recessive loss-of-function mutation in NEK9 (a missense mutation in the middle region) causes a lethal skeletal dysplasia (lethal congenital contracture syndrome 10; OMIM 609798), and patient fibroblasts showed a defect in primary cilia formation47. This evidence concerns the gene NEK9 and NEK9-related lethal skeletal dysplasia.