New molecular mechanisms of craniosynostosis

This project will focus on the genetic causes of craniosynostosis, the premature fusion of one or more sutures separating the bones of the skull vault. A complex network of developmental mechanisms is involved in patterning and maintaining this complex system of bones, and a variety of genetic mutations can affect these processes to cause serious skull malformations. Oxford is a leading national referral centre in the surgical treatment of these malformations, enabling study of the entire process by which they arise from patient to mutation, and from mouse model to molecular pathogenesis.

For the study of clinical samples, both the Oxford-based Genetics of Craniofacial Malformations Study and the Genomics England 100,000 Genomes Project will provide opportunities for discovery. A defined project to investigate the pathophysiological mechanisms of mutations in the homeodomain transcription factor PRRX1 in craniosynostosis has already been identified. In parallel, bioinformatic analysis of in-house and Genomics England data will be undertaken to identify and evaluate new disease genes in craniosynostosis. For the strongest candidate mutations, resequencing will be performed on DNA samples from a large panel of patients currently lacking a genetic diagnosis, to seek independent examples of causative mutations, and to identify genotype-phenotype correlations. Initial functional analysis may include cDNA studies to identify abnormal splicing and/or mRNA instability.

Following careful evaluation of gene candidates, further functional analysis may involve modelling of selected mutations in mice to obtain additional evidence for causation and to investigate pathophysiology. This will involve targeting specific mutations using CRISPR/Cas9 genome editing, analysing the phenotypes of mutant mice using skeletal preparations and micro-CT scanning, and functional studies potentially including single cell transcriptomics, investigation of epigenetic signatures, and analysis of protein levels and activation.