1. Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu 214000, P.R. China
2. Genesky Diagnostics Inc., Suzhou, Jiangsu 215000, P.R. China
3. Department of Family Planning, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, Jiangsu 214000, P.R. China