[1] Univ Wales Hosp, Inst Med Genet, Cardiff CF4 4XW, S Glam, Wales
[2] Stirling Royal Infirm, NHS Trust, Stirling FK8 2AU, Scotland
[3] Univ Wales Coll Med, Cardiff CF4 4XN, S Glam, Wales
[4] Univ Dundee, Ninewells Hosp & Med Sch, Dept Pathol, Dundee DD1 9SY, Scotland
[5] Univ Wales Hosp, Dept Cardiol, Cardiff CF4 4XW, S Glam, Wales
[6] Aberdeen Royal Infirm, Aberdeen Royal Hosp, NHS Trust, Dept Med Genet, Aberdeen, Scotland
[7] Western Gen Hosp, Dept Med Genet, Edinburgh EH4 2XU, Midlothian, Scotland