Early Second Trimester Asymmetric Growth and Mosaic Triploid Liveborn

Background: Mosaic triploidy is uncommon in a liveborn. There have been no previous reports of prenatally diagnosed diploid/triploid mosaicism by amniocentesis. We present a case of prenatally diagnosed diploid/triploid mosaicism. Case: A 26 year old G3P1 presented for ultrasound at 21 weeks 5 days following a positive quad screen. Asymmetrical growth restriction, abnormal hand positioning and suspected heart defect were noted. Amniocentesis revealed mosaic triploidy; 69, XXX (10)/46, XX (6). Infant was delivered at 37 weeks by repeat cesarean section. Neonatal cord blood karyotype confirmed mosaic triploidy; 69, XXX (2)/46, XX (18). Conclusion: Prenatal diagnosis and subsequent outcome of a liveborn mosaic diploid/triploid infant has not been previously described. Our case demonstrates that diploid/triploid mosaicism may be diagnosed by amniocentesis and that the pregnancy may be managed to live birth near term.