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  • Stephen Twigg

 About the Research

Using a combination of patient samples and mouse models, we study the causes and developmental origins of skull malformation. The work ranges from screening human DNA for new mutations, to use of genome editing and single cell transcriptomics to model and analyse the developmental causes of these malformations in mice. Projects on offer would particularly appeal to students interested in genetics, genomics and developmental mechanisms and for whom clinical application is a key motivator. There will be particular opportunities to learn core bioinformatics skills, perform single cell analysis, and use genome editing to generate and characterise mouse models to understand disease mechanisms.

Our work is focused on the causes of skull malformations, particularly 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 us study the entire process by which these arise from patient to mutation, and from mouse model to molecular pathogenesis. 

For the study of clinical samples, massively parallel genome sequencing has revolutionised the identification of Mendelian disease genes. Our group has identified many new human disease genes using this approach and the UK’s Genomics England 100,000 Genomes project (, NHS Genomic Testing and our own genome analysis programme will provide further opportunities for discovery during the course of the studentship. To investigate pathophysiology, we model carefully selected mutations in mice. We still know very little about what happens biologically in the cranial sutures themselves: these structures must achieve a delicate balancing act of enabling growth of new bone at the margins of the suture, whilst also ensuring that the mid-part of the suture remains open along its entire length. We explore how the suture works by mapping out the cellular hierarchy of activities from undifferentiated stem cell to fully formed osteoblast, comparing results between normal sutures and those from mice with targeted mutations. 

In clinical genome analysis, you could follow through the entire experimental process from choice of DNA sample to identification of a new disease gene, learning how DNA is processed for sequencing and how the raw sequence is filtered. Once the vast majority of sequence variants have been excluded, you will use a combination of bioinformatics tools, biological knowledge and analysis of the literature to identify the most likely candidate changes. You will then verify these in the original samples and, for the strongest candidate mutations, analyse the DNA sequence of a large number of patient samples to seek independent support. For mouse model analysis, you could target specific mutations using CRISPR/Cas9 genome editing and analyse the phenotypes of mutant mice using skeleton/cartilage staining, histology and RNA in situ hybridisation, micro-CT scanning, single cell transcriptomics, investigation of epigenetic signatures, and analysis of protein levels and activation. Our group has close links with the MRC National Mouse Genetic Network (NMGN) ensuring access to cutting edge expertise in mouse model generation and phenotyping.

Additional supervision may be provided by Professor Andrew Wilkie.

Please see the Weatherall Institute for Molecular Medicine (WIMM) for information about applications for a DPhil in Medical Sciences with groups based in the WIMM.


Training Opportunities

You will learn how to use a wide range of web resources to interpret genomic information from human, mouse and other species. For experimental work you will be exposed to a wide variety of techniques including cell culture, fluorescence-activated cell sorting (FACS), microscopy, single cell transcriptomics and next generation sequencing, as well as basic molecular biology methodologies for analysing DNA, RNA and protein, all of which are essential for functional characterisation of mutations. If working on mice you will obtain your own personal license and undergo training in husbandry and experimental analysis.

Acquisition of bioinformatics skills is central to progress in biology, whether applied to genome sequence analysis, single cell transcriptomics, or epigenomics. Full support will be available through the WIMM Centre for Computational Biology. For clearly defined projects requiring advanced bioinformatics skills there will be the opportunity for more intensive training through the in-house Computational Genomics: Analysis and Training (CGAT) programme.

Students will be enrolled on the MRC Weatherall Institute of Molecular Medicine DPhil Course, which takes place in the autumn of their first year. Running over several days, this course helps students to develop basic research and presentation skills, as well as introducing them to a wide range of scientific techniques and principles, ensuring that students have the opportunity to build a broad-based understanding of differing research methodologies. 

Generic skills training is offered through the Medical Sciences Division's Skills Training Programme. This programme offers a comprehensive range of courses covering many important areas of researcher development: knowledge and intellectual abilities, personal effectiveness, research governance and organisation, and engagement, influence, and impact. Students are actively encouraged to take advantage of the training opportunities available to them.

As well as the specific training detailed above, students will have access to a wide range of seminars and training opportunities through the many research institutes and centres based in Oxford.

The Department has a successful mentoring scheme, open to graduate students, which provides an additional possible channel for personal and professional development outside the regular supervisory framework. We hold an Athena SWAN Silver Award in recognition of our efforts to build a happy and rewarding environment where all staff and students are supported to achieve their full potential.




Twigg SRF, et al (2013). Reduced dosage of ERF causes complex craniosynostosis in humans and mice, and links ERK1/2 signalling to regulation of osteogenesis. Nature Genet 45:308-313.


Twigg, SRF & Wilkie AOM (2015). A genetic-pathophysiological framework for craniosynostosis. Am J Hum Genet 97:359-77.


Twigg SRF, et al (2015). Gain-of-function mutations in ZIC1 are associated with coronal craniosynostosis and learning disability. Am J Hum Genet 97:378-388.


Miller KA, Twigg SRF, et al (2017). Diagnostic value of exome and whole genome sequencing in craniosynostosis. J Med Genet 54: 260-268.


Goos JAC, (15 authors), Twigg SRF (2019). A de novo point mutation in BCL11Bleads to loss of interaction with the NuRD and PRC2 transcriptional complexes and is associated with craniosynostosisHum Mol Genet 28:2501-2513.


Farmer DT, (13 authors), Twigg SRF (2021). The developing mouse coronal suture at single-cell resolution. Nat Commun 12:4797.


Hyder Z, (22 authors), Wilkie AOM (2021). Evaluating the performance of a clinical genome sequencing program for diagnosis of rare genetic disease, seen through the lens of craniosynostosis. Genet Med 23:2360-2368.


Tooze RS, (21 authors), Twigg SRF, Wilkie AOM (2023). Pathogenic variants in the paired-related homeobox 1 gene (PRRX1) cause craniosynostosis with incomplete penetrance. Genet Med 25:100883.