Mosaic trisomy 17 at amniocentesis: Prenatal diagnosis, molecular genetic analysis, and literature review

Low-level mosaicism for trisomy 17 detected by amniocentesis without ultrasound abnormality can be associated with a favorable outcome. Molecular genetic analysis of uncultured amniocytes at repeat amniocentesis is useful for genetic counseling. A review of the literature shows a correlation between an adverse fetal outcome and a higher trisomy 17 mosaicism level at amniocentesis associated with ultrasound abnormality.