Discordant embryonic aneuploidy testing and prenatal ultrasonography prompting androgen insensitivity syndrome diagnosis

BACKGROUND:: Multimodal prenatal screening for developmental pathology is increasingly common. In this case, definitive prenatal diagnosis of androgen insensitivity syndrome was diagnosed after discordant results from karyotypes determined by embryonic preimplantation genetic screening and antenatal ultrasound results. CASE:: A 38-year-old woman, gravida 2 para 0010, undergoing in vitro fertilization with preimplantation genetic screening transferred one male and one female embryo. An anatomic ultrasonogram revealed two fetuses with female genitalia. Cell-free fetal DNA analyzed using noninvasive prenatal screening demonstrated Y chromosome material, and amniocentesis confirmed one 46,XX and one 46,XY fetus. Sequencing of the androgen receptor for the 46,XY fetus identified a mutation. CONCLUSION:: With increased use, discordance among prenatal testing modalities such as preimplantation genetic screening, noninvasive prenatal screening, and ultrasonography will become more common requiring expert navigation to identify true pathology.