1. Department of Pathology and Cell Biology; Columbia University; New York NY USA
2. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health; Bethesda MD USA
3. Departments of Obstetrics and Gynaecology; Mount Sinai Hospital and University of Toronto; Toronto Canada
4. Departments of Obstetrics and Gynaecology; University Hospitals Leuven; Leuven Belgium
5. Institute of Women's Health, University College London; London UK
6. Inova Alexandria Hospital; Alexandria VA USA
7. North East Thames Regional Genetics Service; Great Ormond Street NHS Foundation Trust; London UK
8. Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health; London UK