(93) Maternal sex chromosome aneuploidy identified through noninvasive prenatal screening: clinical profile and patient experience

Non-invasive prenatal screening (NIPS) may incidentally identify maternal aneuploidies that have health implications, such as maternal monosomy X. We evaluated patients’ experience with counseling and follow-up diagnostic testing after NIPS flags a potential maternal sex chromosome aneuploidy (SCA). We hypothesized that patients were routinely offered, and completed, diagnostic follow-up genetic testing after SCA is detected on NIPS.

Study Design:

Patients who underwent NIPS at two reference laboratories between 2012 and 2021 and had test results that were consistent with possible or probable maternal SCA were contacted with a link to an anonymous survey. Survey topics included demographics, health history, pregnancy history, counseling, and follow-up testing.

Results:

269 patients responded to the anonymous survey, and 83 of these individuals also completed one follow-up survey (Figure 1). Most (75%) received pre-test counseling. 80% were offered fetal genetic testing during the pregnancy, which was completed in 25% of respondents. Only 35% of patients completed diagnostic maternal testing (Figure 2). Patients with monosomy X-related phenotypes were more likely to have follow up testing that led to a diagnosis of monosomy X in 14 cases (6%, Figure 2). Two patients with diagnostic testing that confirmed mosaic Turner’s had no phenotypical findings. No other clinical or demographic factors were associated with an abnormal maternal karyotype on diagnostic evaluation.

Conclusion:

Follow up counseling and testing after a high-risk NIPS result suggestive of maternal SCA is heterogenous in this cohort and may be frequently incomplete. We observed that the presence of Turner’s phenotype increased the likelihood of diagnostic testing in this cohort. However, the incomplete penetrance of SCA phenotypes in the population could hinder the performance of this strategy. Health outcomes may be affected by SCA and an effective strategy for definitive testing could improve the provision, delivery, and quality of post-test counseling.