Biallelic variants in <i>DNAH10</i> are associated with skeletal developmental abnormalities and ciliary dysfunction.

Abstract

Primary cilia are essential for skeletal development by coordinating key signalling pathways in osteoblasts and chondrocytes. While pathogenic variants in approximately 40 genes have been linked to skeletal ciliopathies, additional causative genes remain to be identified. Although DNAH10 is well characterised in motile cilia, its role in primary cilia remains unclear. Whole-exome sequencing was performed in two individuals with skeletal developmental abnormalities and identified biallelic <i>DNAH10</i> variants. In vitro assays were used to assess the effects of these variants on DNAH10 protein abundance. <i>Dnah10</i> knockout mice were generated to investigate the associated skeletal phenotypes and underlying mechanisms. Biallelic <i>DNAH10</i> variants were identified in two individuals with skeletal developmental abnormalities. In vitro, these missense variants were associated with reduced DNAH10 protein abundance. <i>Dnah10</i>-deficient mice recapitulated key skeletal features, including polydactyly, impaired cartilage development and abnormal ossification. Mechanistically, <i>Dnah10</i> loss was associated with abnormal primary cilia morphology, attenuated Hedgehog signalling, impaired osteoblast differentiation and defective chondrocyte maturation. Our findings support <i>DNAH10</i> as a candidate gene associated with skeletal developmental abnormalities and ciliary dysfunction and suggest a previously underappreciated role for DNAH10 in primary cilia-related skeletal development beyond its established role in motile cilia.