1. Antenatal Testing Center Alexandria Hospital; Alexandria VA USA
2. Department of Obstetrics and Gynecology; Georgetown University Hospital; Washington D.C. USA
3. Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Institutes of Health; Bethesda MD USA
4. Departments of Pathology and Cell Biology; Columbia University; New York NY USA
5. Department of Obstetrics and Gynaecology; Mount Sinai Hospital and University of Toronto; Toronto Canada
6. Departments of Obstetrics and Gynaecology; University Hospitals Leuven; Leuven Belgium
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