Received: 28 November 2018
Revised: 15 May 2019
Accepted: 21 May 2019
First Online: 11 June 2019
Compliance with ethical standards
: SW and JB have received travel support from Illumina to attend conferences in Baltimore, USA and Barcelona, Spain. EB, KLT, EO, HW and JCT report no conflicts of interest.
: Ethical approval was granted for this study by the University of Oxford Central University Research Ethics Committee [R51851/RE001].