Trisomy 7 in chorionic villi: Follow‐up studies of pregnancy, normal child, and placental clonal anomalies

Abstract

Cytogenetic study of chorionic villi sampled because of advanced maternal age revealed, after overnight culture, an apparently non‐mosaic trisomy 7. Amniocentesis showed exclusively normal mitoses, and the pregnancy continued normally. One hundred mitoses from cord blood of the normal newborn revealed a non‐mosaic 46,XX complement. No cells with a proven trisomy 7 were found in cultures from either of two biopsies of the morphologically normal placenta, but the peripheral biopsy showed in multiple cultures an abnormal clone: 47,XX, + 20,‐2,‐21, + t(2;21)(p13;q22). To our knowledge, this is the first case of non‐mosaic trisomy 7 detected on CVS which has had follow‐up studies of amniotic fluid, cord blood, and term placenta.