title: Prenatal diagnosis of trisomy 20 mosaicism indicating an extra embryonic origin.
abstract: An additional case of amniotic fluid trisomy 20 mosaicism is presented. After careful counselling, the pregnancy continued and a phenotypically normal female was delivered. This case of amniocyte mosaicism establishes the source of aneuploid cell line as amnion. Since an extra-embryonic origin of the mosaicism has been confirmed, this should be carefully considered as a real possibility in counselling such families.
mesh_terms: D002890:Chromosomes, Human, Pair 20; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D009030:Mosaicism; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014314:Trisomy