Fetal Screening for Chromosomal Abnormalities

Very young and advanced maternal age strongly elevates the occurrence of nonchromosomal congenital anomalies: a systematic review and meta-analysis of population-based studies

BACKGROUND

Nonchromosomal congenital anomalies (NCAs) are the most common cause of infant mortality and morbidity. The role of maternal age is well known, although the specifics are not thoroughly elucidated in the literature.

OBJECTIVE

To evaluate the role of maternal age in the incidence of NCAs and to pinpoint age groups at higher risk to refine screening protocols.

STUDY DESIGN

A systematic review and meta-analysis were conducted following the PRISMA 2020 guidelines and Cochrane Handbook. Searches were performed on October 19, 2021, across MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. Population-based studies assessing the impact of maternal age on the incidence of NCAs in pregnant women were included, without restrictions on age range, country, or comorbidities. A random-effects model was used for pooling effect sizes, considering the heterogeneity across studies.

RESULTS

From 15,547 studies, 72 were synthesized. Maternal age >35 showed an increased NCA risk (risk ratio [RR]: 1.31, confidence interval [CI]: 1.07 -1.61), rising notably after>40 (RR: 1.44, CI: 1.25 -1.66). The latter changes to 1.25 (CI: 1.08 -1.46) if the co-occurrence of chromosomal aberrations is excluded. Specific anomalies like cleft lip/palate (>40, RR: 1.57, CI: 1.11 -2.20) and circulatory system defects (>40, RR: 1.94, CI: 1.28 -2.93) were significantly associated with advanced maternal age. Conversely, gastroschisis was linked to mothers <20 (RR: 3.08, CI: 2.74 -3.47).

CONCLUSION

The study confirms that both very young and advanced maternal ages significantly increase the risk of NCAs. There is a pressing need for age-specific prenatal screening protocols to better detect these anomalies, especially considering the current trend of delayed childbearing. Further research is required to fully understand the impact of maternal age on the prevalence of rarer NCAs.

Aspiring toward equitable benefits from genomic advances to individuals of ancestrally diverse backgrounds

Advancements in genomic technologies have shown remarkable promise for improving health trajectories. The Human Genome Project has catalyzed the integration of genomic tools into clinical practice, such as disease risk assessment, prenatal testing and reproductive genomics, cancer diagnostics and prognostication, and therapeutic decision making. Despite the promise of genomic technologies, their full potential remains untapped without including individuals of diverse ancestries and integrating social determinants of health (SDOHs). The NHGRI launched the 2020 Strategic Vision with ten bold predictions by 2030, including "individuals from ancestrally diverse backgrounds will benefit equitably from advances in human genomics." Meeting this goal requires a holistic approach that brings together genomic advancements with careful consideration to healthcare access as well as SDOHs to ensure that translation of genetics research is inclusive, affordable, and accessible and ultimately narrows rather than widens health disparities. With this prediction in mind, this review delves into the two paramount applications of genetic testing-reproductive genomics and precision oncology. When discussing these applications of genomic advancements, we evaluate current accessibility limitations, highlight challenges in achieving representativeness, and propose paths forward to realize the ultimate goal of their equitable applications.

A rapid PCR-free next-generation sequencing method for comprehensive diagnosis of chromosome disease syndromes in prenatal samples

The aim of this study is to investigate the application performance of rapid copy number variation sequencing (rCNV-seq) technology for the detection of chromosomal abnormalities during prenatal diagnosis. Samples were collected from 424 pregnant women who were at high-risk for noninvasive prenatal screening in Kunming Maternal and Child Care Hospital from January 2018 to May 2022. rCNV-seq technique was used to detect fetal chromosome abnormalities and compare the results with that of chromosomal karyotype analysis. The Result showed that 330 (77.83%, 330/424) cases indicated chromosomal abnormalities among 424 high-risk pregnant women who underwent rCNV-seq. Moreover, 94 (22.17%, 94/424) cases were discovered to have copy number variations. Among the 330 fetuses with chromosomal abnormalities, common autosomal aneuploidy was observed in 203 cases (47.87%, 203/424) and sex chromosome aneuploidy was observed in 91 cases (21.46%, 91/424). Moreover, the abnormalities in multiple chromosomes were discovered in 33 cases (7.78%, 33/424), and the rare autosomal aneuploidy was observed in 3 cases (0.71%, 3/424). There were 63 fetuses (14.86%, 63/424) with pathogenic CNVs among the 94 fetuses with variable copy numbers. Of the 245 pregnant women who voluntarily selected G-band karyotyping, 1 fetus with copy number variation had normal karyotype results, and the remaining women were consistent with rCNV-seq. Our study revealed that rCNV-seq has higher accuracy in detecting common trisomy and can also detect chromosomal microdeletions or microduplications that cannot be detected by G-banding karyotype analysis. There is no effective treatment for chromosomal diseases, so it is particularly important to prevent chromosomal diseases through genetic counseling and prenatal diagnosis of chromosomal diseases.