In summary, we describe recessive loss-of-function mutations in DNAH9 encoding the ODA β-HC DNAH9 as a cause for laterality defects without or with subtle symptoms of airway cilia dysfunction. The mild respiratory phenotype results from only distally impaired axonemal bending, consistent with DNAH9 localization and distinct, distally restricted loss of ODA components. In parallel, Fassad et al. also found a reduction of ODA components in the distal ciliary compartment in individuals with recessive variants in DNAH9,52 consistent with our findings. We conclude that DNAH9 is essential for ODA type 2 assembly and our data indicate that docking of ODAs type 2 occurs via direct interaction of DNAH9 with the docking complex protein CCDC114.