1 Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK. j.j.fryett@newcastle.ac.uk.
2 JDRF/Wellcome Diabetes and Inflammation Laboratory, Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
3 Department of Biostatistics, University of Liverpool, Liverpool, UK.
4 Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK. heather.cordell@newcastle.ac.uk.