Willsey, H. | Search bioRxiv

bioRxiv2024

Koolen-de Vries Syndrome causal gene KANSL1 is required for motile ciliogenesis

Koolen-de Vries Syndrome (KdVS), characterized by hypersociability, intellectual disability, and seizures, is caused by pathogenic variants in the gene KANSL1, which encodes a chromatin regulator in the NSL complex that also directly functions in mitotic spindle microtubule stability. Here we explored whether KANSL1 functions at the cilium, a microtubule-rich organelle critical for brain development, neuronal excitability, and sensory integration. Leveraging the Xenopus model, we found that Kansl1 is highly expressed in developing ciliated tissues and localizes within motile cilia. Moreover, Kansl1 depletion caused ciliogenesis defects that could be partially rescued by human KANSL1. Based on these findings, we explored the prevalence of cilia-related clinical features including structural heart defects, hypogonadism, and structural respiratory defects among 99 individuals with KdVS, ages 1 month to 37 years old. To directly test if KdVS causes ciliary dysfunction in humans, we measured the well-established ciliary functional biomarker, nasal nitric oxide, in 11 affected individuals and observed a significant decrease when compared to unaffected family members. Together, this work establishes a ciliary contribution of KANSL1 mutations to KdVS. This work adds to a growing literature highlighting the relevance of the cilium to neurodevelopmental disorders, particularly to those impacting sociability. Going forward, KANSL1 provides a unique opportunity to study a monogenic mechanism of hypersociability that may be useful in elaborating the molecular underpinnings of social behavior.

developmental biology↗

bioRxiv2024

Ciliary biology intersects autism and congenital heart disease

Autism spectrum disorder (ASD) commonly co-occurs with congenital heart disease (CHD), but the molecular mechanisms underlying this comorbidity remain unknown. Given that children with CHD come to clinical attention by the newborn period, understanding which CHD variants carry ASD risk could provide an opportunity to identify and treat individuals at high risk for developing ASD far before the typical age of diagnosis. Therefore, it is critical to delineate the subset of CHD genes most likely to increase the risk of ASD. However, to date there is relatively limited overlap between high confidence ASD and CHD genes, suggesting that alternative strategies for prioritizing CHD genes are necessary. Recent studies have shown that ASD gene perturbations commonly dysregulate neural progenitor cell (NPC) biology. Thus, we hypothesized that CHD genes that disrupt neurogenesis are more likely to carry risk for ASD. Hence, we performed an in vitro pooled CRISPR interference (CRISPRi) screen to identify CHD genes that disrupt NPC biology similarly to ASD genes. Overall, we identified 45 CHD genes that strongly impact proliferation and/or survival of NPCs. Moreover, we observed that a cluster of physically interacting ASD and CHD genes are enriched for ciliary biology. Studying seven of these genes with evidence of shared risk (CEP290, CHD4, KMT2E, NSD1, OFD1, RFX3, TAOK1), we observe that perturbation significantly impacts primary cilia formation in vitro. While in vivo investigation of TAOK1 reveals a previously unappreciated role for the gene in motile cilia formation and heart development, supporting its prediction as a CHD risk gene. Together, our findings highlight a set of CHD risk genes that may carry risk for ASD and underscore the role of cilia in shared ASD and CHD biology.

developmental biology↗