Variation Exists in Service Delivery: Similarities and Differences in the Provision of a Whole Genome Sequencing Service for Paediatric Rare Disease Patients in the National Health Service in England.

Introduction: The National Health Service (NHS) in England is the first to offer whole genome sequencing (WGS) as part of standard care. As a high-income country with a universal healthcare system, England contributes a valuable perspective to global developments in WGS.

Methods: We used an implementation science approach with mixed methods to characterise delivery of WGS for paediatric rare diseases: observations and field notes of consent appointments in clinical genetics and mainstream settings and follow-up qualitative semi-structured interviews with the clinical team. Process maps were developed for each department to identify similarities and variations between sites and thematic analysis of interview data to understand barriers and facilitators.

Results: Data collection occurred in 12 departments (7 genetic, 3 neurology, 1 cardiology, and 1 general paediatric) across 7 NHS Trusts. 26 observations of 21 healthcare professionals were conducted, alongside 19 follow-up interviews. Two master maps were developed - one for clinical genetics and one for the mainstream. We identified 11 steps involved in delivering WGS, including 9 variations and 9 similarities. We identified most variation in the processes related to the "who," "when," "how," and "where" as these were aspects that could be adapted to fit into the specific set-up of the department. Barriers included reluctance to uptake in the mainstream and difficulties tracking samples.

Conclusion: Recommendations include developing standard operating procedures and hiring healthcare professionals responsible for facilitating consent alongside administrative aspects. These would reduce the burden on clinical geneticists and improve turnaround times as well as contribute to streamlining and standardisation of the service.