1. Department of Prenatal Diagnosis, Laboratory of Clinical Genetics, Maternity and Child Health Care Hospital, Yancheng, Jiangsu 224001, P.R. China
2. Department of Clinical Reproductive Medicine, State Key Laboratory of Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
3. Department of Prenatal Diagnosis, State Key Laboratory of Reproductive Medicine, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210004, P.R. China