Discrepancy between non-invasive prenatal testing result and fetal karyotype caused by rare confined placental mosaicism: A case report

Table 2 Timeline for the care

Gestational age (wk)	Examination items	Results
15 + 1	Serum Down’s screening	High risk for trisomy 21
15 + 3	NIPT	High risk for trisomy 21, low risk for sex chromosome aneuploidy
19 + 2	Amniocentesis (CNV-seq and karyotype analysis)	47,XXY
22 + 5	Abortion, collected fetal muscle tissue, umbilical cord and placental samples	Fetal muscle tissue and umbilical cord: 47,XXY placenta: A mosaic of 47,XY,+21; 47,XXY; and 46,XY

NIPT: Noninvasive prenatal testing; CNV-seq: Copy-number variation sequencing.