Multiple Aneuploidy Pattern Detected by Non-invasive Prenatal Screening in Successive Pregnancies [25K

Abstract

INTRODUCTION: We present a case where non-invasive prenatal screening (NIPS) detected a similar pattern of multiple aneuploidies in sequential pregnancies. METHODS: Case Presentation (with patient consent): A 25 year-old G3P2 patient had NIPS, by massively parallel sequencing (MPS), in her second and third pregnancies. Her first NIPS result was positive for trisomies 18 and 21. Further bioinformatics review revealed possible partial trisomy 13 and complete trisomies 14 and 20, in addition to the previously reported trisomies. NIPS by MPS repeated at another lab was non-reportable. Amniocentesis revealed normal karyotype, microarray, FISH for the chromosomes of interest, and chromosome 14 uniparental disomy testing. Maternal karyotype, microarray, and chromosomal breakage studies were normal. Patient had a negative oncology evaluation. Patient had an insignificant medical and medication history. Patient delivered a healthy girl. Placenta was small with a normal karyotype. Her current pregnancy shows a similar NIPS pattern. Patient declined amniocentesis and further aneuploidy screening. Second trimester ultrasound detected fetal hyperechoic bowel. Repeat maternal chromosomal breakage studies were normal. CONCLUSION: NIPS analyzes cell-free DNA in maternal blood originating from maternal and cytotrophoblast cells. The similar NIPS pattern in both pregnancies indicates a likely maternal etiology. When multiple aneuploidies are observed by NIPS, possible etiologies include maternal benign tumor or malignancy and fetal, placental or maternal chromosome abnormalities. However, subsequent fetal and maternal evaluations were normal. This case highlights that NIPS may yield unexpected results that are not representative of the fetal or maternal karyotypes and an extensive multi-specialty work-up may be recommended in these scenarios.