Non-invasive Prenatal Genetic Testing Research Articles

Towards DNA: Issues and Implications of Non-invasive Prenatal Genetic Testing

Non-invasive prenatal diagnosis (NIPD) will soon become the standard of care for prenatal genetic testing. NIPD uses DNA and has the potential to sequence the entire fetal genome and detect many diverse traits. Although both the public and midwives support the implementation of NIPD, concerns arise owing to the lack of agreement about what constitutes severe disabling traits. Further, there is limited understanding of the implications of such testing at both the individual and population levels. Midwives and other maternity care providers need to be better educated on all aspects of prenatal genetic testing - the limitations and implications of NIPD, as well as disability traits and living with them - in order to help their clients make truly informed choices.

The detection efficacy of noninvasive prenatal genetic testing (NIPT) for sex chromosome abnormalities and copy number variation and its differentiation in pregnant women of different ages

ObjectiveTo analyze the efficacy of noninvasive prenatal genetic testing (NIPT) in detecting fetal sex chromosome abnormalities and copy number variation (CNV), compare the efficacy between NIPT and serological screening alone, and further analyze the fetal sex chromosome abnormalities and CNV differentiation in pregnant women of different ages, so as to provide a reference for the prevention and control of fetal birth defects. MethodsClinical data from 22,692 pregnant women admitted to our hospital from January 2013 to December 2022 were retrospectively analyzed. All participants underwent serological screening and NIPT screening to compare fetal chromosomal abnormalities between the two screening modalities. 145 women whose fetus were diagnosed as sex chromosome abnormalities and 36 women whose fetus were diagnosed as CNV abnormalities based on NIPT screening were selected for prenatal diagnosis by amniocentesis or karyotyping. Taking prenatal diagnosis as the standard, the four-grid table method was used to detect the positive predictive value of NIPT screening for fetal sex chromosomal abnormalities and CNV. According to the age, pregnant women were divided into 18–30 years old (n = 9844), 31–35 years old (n = 7612), >35 years old (n = 5236), and then the detection rates of sexual fetal chromosomal abnormalities, CNV and total chromosomal abnormalities were compared in pregnant women. ResultsAmong the 22,692 pregnant women in this study, the high-risk proportion of serologic screening with 4.38% was higher than that of NIPT screening with 1.93% (P < 0.05). Among the 145 women with fetal sex chromosome abnormalities screened by NIPT, 122 cases of fetal sex chromosome abnormalities were diagnosed prenatally, including 45, X/47, XXX/47, XYY/47, XXY. The positive predictive values of NIPT screening were 25.00%, 58.82%, 85.71%, and 85.71%, respectively, with an overall predictive value of 44.26%. The positive predictive value of fetal sex chromosome abnormalities in NIPT screening was higher than that of serological screening (P < 0.05). Among the 36 pregnant women with fetal CNV, NIPT screening showed that CNVs≤10 Mb and CNVs>10 Mb were 33.33% and 66.67%, respectively. There were 12 cases of prenatal diagnosis of fetal CNV, among which the NIPT-screened positive predictive values of fetal copy number deletion, duplicate, deletion and duplicate were 50.00%, 57.14% and 100.00%, respectively, with an overall predictive value of 58.33%. The positive predictive value of CNV in NIPT screening was higher than that of serological screening without statistically significant difference (P > 0.05). The results of NIPT screening showed that the detection rate of fetal sex chromosome abnormalities and total abnormalities of pregnant women over 35 years of age was significantly higher than that of pregnant women aged 18–30 and 31–35 years (P < 0.05). ConclusionNIPT screening could greatly improve the detection efficacy of fetal sex chromosome abnormalities, CNV and other chromosome abnormalities, and decline the false positive rate. However, the positive predictive value of NIPT screening was relatively low, and further prenatal testing and genetic counseling are still required. In addition, NIPT screening for fetal sex chromosome abnormalities, and the detection rate of total abnormalities in pregnant women older than 35 years old were increased significantly, and pregnancy at an advanced age may be one of the risk factors for fetal chromosomal abnormalities.

Prenatal diagnosis of bone dysplasias.

Bone dysplasias are individually rare but collectively common. The prenatal diagnosis of bone dysplasias, especially perinatally lethal dysplasias, is of major interest to obstetric services. The current nosology of genetic skeletal disorders addresses over 400 disorders. However, in clinical practice, we encounter only a limited number of disorders, such as FGFR3-related dysplasias, osteogenesis imperfecta, and type II collagenopathies. The recent development of non-invasive prenatal genetic testing using cell-free fetal DNA in maternal blood samples has had a major impact on the prenatal diagnosis of genetic diseases. However, imaging examinations remain critical for the final diagnosis of bone dysplasias because molecular testing only shows genetic variants, and not their pathogenicity - most variants are clinically insignificant. Bone dysplasias are typically suspected when limb shortening is identified by screening ultrasound. Further assessment can be followed by more detailed ultrasound, magnetic resonance imaging (MRI), and CT. Based on these data, rational decision-making is feasible, even when the definitive prenatal diagnosis is not feasible. Here, we highlight key images of common bone dysplasias obtained by currently available modalities.

Changes in the number of babies born with Down syndrome in Japan.

The number of babies born with Down syndrome has changed in recent years because of widespread availability of prenatal screening and advanced maternal age at delivery. In Japan, which has no public institutions that record data on babies born with chromosomal abnormalities (including Down syndrome), the accurate number remains unknown. The Japan Association of Obstetricians and Gynecologists Birth Defects Monitoring Program (hereafter the JAOG Program) is the only national survey of congenital anomalies in Japan. Using data from this survey and vital statistics, we investigated the changes in the number of babies born with Down syndrome in Japan from 2006 to 2019. On performing linear regression analysis with the proportion of babies born with Down syndrome as the response variable, and the proportion of mothers giving birth at the age of 35 years or older as the explanatory variable, the regression coefficient was 0.0054 (p < 0.001). The proportion of mothers giving birth at the age of 35 years or older was useful for predicting the proportion of babies born with Down syndrome. This proportion has increased since 2006 but has remained almost unchanged since 2015. In 2019, it was 1/734. This study revealed that the proportion of mothers giving birth at the age of 35 years or older strongly affected the proportion of babies born with Down syndrome. We assume that the proportion of babies is slightly affected by the increased number of pregnant women currently undergoing prenatal screening after the introduction of noninvasive prenatal genetic testing in 2013.

Clinical Validation of Fetal cfDNA Analysis Using Rolling-Circle-Replication and Imaging Technology in Osaka (CRITO Study).

Background: Noninvasive prenatal genetic testing (NIPT) has been adopted as the first choice for aneuploidy screening. The purposes of this study were to investigate the accuracy of Vanadis® NIPT (hereafter CRITO-NIPT) in order to gain a deeper insight into the reasons for discrepancies, as well as to discuss the role of fetal ultrasound. Methods: Between 2019 and 2020, CRITO-NIPT was performed in 1218 cases of patients who underwent CVS or amniocentesis after a detailed fetal ultrasound exam and genetic counseling. The CRITO-NIPT results were compared with the genetic results. In cases of test discrepancies, the placentae were collected for detailed genetic research, and the pre-procedure fetal ultrasound findings were referred to. Results: The positive predictive value of T21, T18, and T13 was 93.55%, 88.46%, and 100%, respectively. In 90% of the of false positive (FP) cases, the placentae were examined. In 75% of the CRITO FP-T21 cases, placental mosaicism, or a demised twin’s T21, were confirmed. There were complicated mosaic cases, including tetrasomy 21/trisomy7 and monosomy 21/trisomy21 cases. In one of three no-call cases, an intermediate deletion of chromosome 13 was detected. Conclusions: The CRITO study investigated the mechanism of false positives, and the detailed mechanisms in mosaic and no-call cases. There have hitherto been no reports that have provided insight by partitioning the placenta to compare the NIPT and invasive test results, nor that have provided detailed ultrasound findings in the cases of discordant results, revealing the demonstrated importance of, and necessity for, detailed ultrasonography. This article describes the potential of rolling-circle replication as a powerful biosensing platform, as well as the importance of examining the fetus in detail with ultrasound. However, we should remember that the potential applications raise ethical and social concerns that go beyond aneuploidy and its methodology.

Comparing Germany and Israel regarding debates on policy-making at the beginning of life: PGD, NIPT and their paths of routinization

DefinitionThe routinization of prenatal diagnosis is the source of bioethical and policy debates regarding choice, autonomy, access, and protection. To understand these debates in the context of cultural diversity and moral pluralism, we compare Israel and Germany, focusing on two recent repro-genetic “hot spots” of such policy-making at the beginning of life: pre-implantation genetic diagnosis (PGD) and non-invasive prenatal genetic testing (NIPT), two cutting-edge repro-genetic technologies that are regulated and viewed very differently in Germany and Israel, reflecting different medicolegal policies as well as public and bioethical considerations.ArgumentsFirst, we compare policy-making in the context of PGD for HLA (human leukocyte antigen) typing, used to create sibling donors, approved in Israel under specific conditions while prohibited in Germany. Second, we compare policy-making in the context of NIPT, which came under fire in Germany, while in Israel there has been little public debate about it.ConclusionBoth countries justify their contrasting policies as reflecting a concern for the well-being and care of the embryo/child, thus highlighting different concepts of embryo/child protection, (relational) autonomy, family relations, and the impact of religion and history on the promotion/protection of life. We use the juxtaposition of PGD and NIPT to highlight some inconsistencies in policies concerning the protection of extra- and intra-corporeal embryos. We conclude by drawing on the comparison to show how national variations exist alongside co-evolution.

Overview and recent developments in cell-based noninvasive prenatal testing.

Investigators have long been interested in the natural phenomenon of fetal and placental cell trafficking into the maternal circulation. The scarcity of these circulating cells makes their detection and isolation technically challenging. However, as a DNA source of fetal origin not mixed with maternal DNA, they have the potential of considerable benefit over circulating cell-free DNA-based noninvasive prenatal genetic testing (NIPT). Endocervical trophoblasts, which are less rare but more challenging to recover are also being investigated as an approach for cell-based NIPT. We review published studies from around the world describing both forms of cell-based NIPT and highlight the different approaches' advantages and drawbacks. We also offer guidance for developing a sound cell-based NIPT protocol.

無侵襲的出生前遺伝学的検査（NIPT）を受検した夫と妻それぞれの思い —結果的にNIPT陰性であった夫婦10組の語りから—

無侵襲的出生前遺伝学的検査（NIPT）を受検した夫と妻それぞれの思い —結果的にNIPT陰性であった夫婦10組の語りから—

942Prevalence of genetic abnormalities in isolated and non-isolated fetal omphalocele

To determine the prevalence of pathogenic/potentially pathogenic genetic findings in isolated and non-isolated fetal omphalocele. This was a retrospective cohort study of patients referred to a single tertiary care center from 2004-2019 with a diagnosis of omphalocele. Images were reviewed to assess for the presence of additional fetal anomalies, which were grouped by organ system. The primary outcome was a suspected/proven genetic variant. Results from screening by non-invasive prenatal testing (NIPT) and genetic testing (including karyotype, microarray, Beckwith-Wiedemann methylation (BWS) studies, and whole exome screening (WES)) were reviewed. Groups were compared using Chi-squared or Fisher’s exact tests, as appropriate. We identified 107 cases of omphalocele with genetic results; 58 (54.2%) were isolated, 49 (45.8%) had additional anomalies. Anomalies were noted in the following organ systems: cardiac (n=32; 65.3%), neurologic (n=11; 34.3%), limb (n=15; 30.6%), craniofacial (n=8; 16.3%), spine (n=7; 14.3%), gastrointestinal (n=6 12.2%), and urological (n=5; 10.2%). Abnormal genetic results occurred in 28% (n=30) of the overall cohort (Table 1). Among those with isolated omphalocele, 19.0% (n=11) had genetic abnormalities, as compared to 38.8% (n=19) with a non-isolated omphalocele (p=0.02). In a those with a non-isolated omphalocele, aneuploidy was the most common genetic finding (Table 2). Aneuploidy was significantly more likely in those with non-isolated omphaloceles (25% vs 8.9%, p=0.02). There was no difference in abnormal genetic findings on microarray or BWS methylation between isolated and non-isolated omphalocele groups (microarray 9.1% vs 11.1%, p=0.82; BWS 12.5% vs 25%, p=0.51). WES was normal for both groups. Non-isolated omphalocele is associated with a substantially increased risk of genetic abnormality, particularly aneuploidy. For isolated cases, the risk of pathological genetic findings remains high. Genetic analysis should be strongly recommended in both isolated and non-isolated omphaloceles.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Non-invasive prenatal testing detects duplication abnormalities of fetal chromosome 12

PurposeThe 12q terminal duplication is a chromosomal structural abnormality that has been rarely reported. The common clinical manifestations include intellectual disability and speech delay. We report two cases of patients with a duplication of chromosome 12q which was discovered incidentally during non-invasive prenatal genetic testing (NIPT). MethodsNext generation sequencing-based NIPT and karyotype analysis confirmed the type and inheritance of the rearrangement, and chromosomal microarray-based analysis also confirmed the end replication. ResultsOne patient had a 18Mb 12q24.21q24.33 duplication. The other patient had a12.04Mb12.q24.31q24.33 duplication and a 9.56Mb deletion in 18p11.32p11.22. The duplicated regions on chromosome 12 and the deletion on chromosome 18 in the patients were pathogenic, and the fetuses may have clinical characteristics, such as mental retardation, facial deformities, and psychomotor retardation. Ultimately, both pregnant women chose to terminate their pregnancy. ConclusionThe cases we reported show that NIPT cannot only detect conventional chromosomes, but can also detect microdeletions and microduplications, which broadens the scope of clinical application for NIPT and provides genetic information for high-risk pregnant women as early as possible.

Qualitative investigation of the factors that generate ambivalent feelings in women who give birth after receiving negative results from non-invasive prenatal testing

BackgroundWomen who receive negative results from non-invasive prenatal genetic testing (NIPT) may find that they later have mixed or ambivalent feelings, for example, feelings of accepting NIPT and regretting undergoing the test. This study aimed to investigate the factors generating ambivalent feelings among women who gave birth after having received negative results from NIPT.MethodsA questionnaire was sent to women who received a negative NIPT result, and a contents analysis was conducted focusing on ambivalent expressions for those 1562 women who responded the questionnaire. The qualitative data gathered from the questionnaire were analyzed using the N-Vivo software package.ResultsEnvironmental factors, genetic counseling-related factors, and increased anticipatory anxiety, affected the feeling of ambivalence among pregnant women. Furthermore, pregnant women desired more information regarding the detailed prognosis for individuals with Down syndrome and living with them and/or termination, assuming the possibility that they were positive.ConclusionsThree major interrelated factors affected the feeling of ambivalence in women. Highlighting and discussing such factors during genetic counseling may resolve some of these ambivalences, thereby enhancing the quality of decisions made by pregnant women.

Advances in non-invasive prenatal gene detection technologies

Non-invasive prenatal testing is a novel detection method which uses sequencing of maternal plasma cell-free DNA in order to screen genetic disease for pregnant women. Compared to traditional prenatal pregnancy tests and disease diagnosis techniques, this technology is non-invasive, convenient, accurate and so on. Since the discovery of cell-free DNA in the peripheral maternal plasma in 1997, non-invasive prenatal genetic testing has been widely used in clinical pregnancy tests and related medical research with the development of high-throughput gene sequencing,it has meaningful achievements in the detection of fetal aneuploidy and enormous challenges in the detection of complex genetic diseases. This article reviews the development of non-invasive prenatal genetic testing technology. Key words: Genetic testing; Prenatal diagnosis; Chromosome aberrations; Genetic diseases,inborn

Direct to consumer versus clinical genetic testing.

There are approximately 250 direct to consumer (DTC) genetic testing companies marketing different testing options such as genetic health risk, carrier status, ancestry, wellness, traits, noninvasive prenatal genetic testing, athleticism, and many others. As a result, choosing the most appropriate test may be daunting when compared with a focused genetic test ordered by a clinician. A wealth of information may be discovered and care must be taken by both consumers and clinicians when deciphering test results. This column highlights considerations when proceeding forward with a DTC genetic test.

Application of non-invasive prenatal genetic testing in prenatal anomaly index screening

Objective To evaluate the value of non-invasive prenatal testing (NIPT) in pregnancies with anomaly in prenatal screening. Methods This was a retrospective study of 2 837 singleton pregnancies who performed NIPT indicated by isolated anomaly in prenatal screening at Guangdong Women and Children Hospital between November 2014 and August 2016. All pregnancies were divided into 3 groups by single indication: advanced maternal age ( AMA, ≥35), abnormal multiples of the median (MoM) in standard screening, increased nuchal translucency thickness (NT, 2.5-3.0 mm). High risk results were verified by prenatal diagnosis. Low risk cases were followed by a 22-26 week anatomical ultrasound examination. All of the cases were followed up and the performance of NIPT for every single indication was evaluated. Results There were total of 2 837 pregnant women who underwent NIPT. Twenty-five of 2 448 pregnancies indicated by AMA had high risk results, among which 17 were confirmed by invasive genetic testing, except 1 case rejecting prenatal diagnosis. In 351 pregnant women with abnormal MoM, NIPT found 3 cases of sex chromosome aneuploidies (SCA) and 2 of them were validated by invasive prenatal diagnosis. Increased NT group included 38 cases, NIPT found 1 case of trisomy 21 which was consistent with karyotype analysis. For common aneuploidies and SCA, the performance of NIPT in the pregnant women who indicated by AMA, abnormal MoM and increased NT were as the follows: the sensitivity were 17/17, 2/2 and 1/1 respectively, the specificity were 99.7% (2 423/2 431), 99.7% (348/349) and 100%(37/37), the positive predictive value were 68% (17/25), 2/3 and 1/1, the negative predictive value were 100% (2 423/2 423), 100% (348/348) and 100% (38/38), respectively. By follow-up survey, a total of 8 cases of abnormal fetus were recorded in NIPT low-risk women, including 5 cases of termination of pregnancy due to abnormal ultrasound findings, 2 cases of abortion as a result of severe obstetric complications and 1 case of stillbirth. Conclusions To the pregnant women who indicated by advanced maternal age, abnormal MoM and increased NT (2.5-3.0 mm), NIPT had satisfactory performance for common aneuploidies, and also had potential value for SCA, resulting in a significant reduction in diagnostic procedures. However, for NIPT low-risk pregnancies, routine antenatal examination and anatomical ultrasound detection would be highly necessary to avoid missing abnormal fetuses.(Chin J Lab Med, 2018, 41: 509-513) Key words: Aneuploidy; Prenatal diagnosis; Genetic testing; Nuchal translucency measurement

How to protect the life of trisomy infants (especially Down syndrome) from eugenic medicine of NIPT (non-invasive prenatal genetic testing)

How to protect the life of trisomy infants (especially Down syndrome) from eugenic medicine of NIPT (non-invasive prenatal genetic testing)

Correction to Imprinted NanoVelcro Microchips for Isolation and Characterization of Circulating Fetal Trophoblasts: Toward Noninvasive Prenatal Diagnostics.

Circulating fetal nucleated cells (CFNCs) in maternal blood offer an ideal source of fetal genomic DNA for noninvasive prenatal diagnostics (NIPD). We developed a class of nanoVelcro microchips to effectively enrich a subcategory of CFNCs, i.e., circulating trophoblasts (cTBs) from maternal blood, which can then be isolated with single-cell resolution by a laser capture microdissection (LCM) technique for downstream genetic testing. We first established a nanoimprinting fabrication process to prepare the LCM-compatible nanoVelcro substrates. Using an optimized cTB-capture condition and an immunocytochemistry protocol, we were able to identify and isolate single cTBs (Hoechst+/CK7+/HLA-G+/CD45-, 20 μm > sizes > 12 μm) on the imprinted nanoVelcro microchips. Three cTBs were polled to ensure reproducible whole genome amplification on the cTB-derived DNA, paving the way for cTB-based array comparative genomic hybridization (aCGH) and short tandem repeats analysis. Using maternal blood samples collected from expectant mothers carrying a single fetus, the cTB-derived aCGH data were able to detect fetal genders and chromosomal aberrations, which had been confirmed by standard clinical practice. Our results support the use of nanoVelcro microchips for cTB-based noninvasive prenatal genetic testing, which holds potential for further development toward future NIPD solution.

Imprinted NanoVelcro Microchips for Isolation and Characterization of Circulating Fetal Trophoblasts: Toward Noninvasive Prenatal Diagnostics.

Circulating fetal nucleated cells (CFNCs) in maternal blood offer an ideal source of fetal genomic DNA for noninvasive prenatal diagnostics (NIPD). We developed a class of nanoVelcro microchips to effectively enrich a subcategory of CFNCs, i.e., circulating trophoblasts (cTBs) from maternal blood, which can then be isolated with single-cell resolution by a laser capture microdissection (LCM) technique for downstream genetic testing. We first established a nanoimprinting fabrication process to prepare the LCM-compatible nanoVelcro substrates. Using an optimized cTB-capture condition and an immunocytochemistry protocol, we were able to identify and isolate single cTBs (Hoechst+/CK7+/HLA-G+/CD45-, 20 μm > sizes > 12 μm) on the imprinted nanoVelcro microchips. Three cTBs were polled to ensure reproducible whole genome amplification on the cTB-derived DNA, paving the way for cTB-based array comparative genomic hybridization (aCGH) and short tandem repeats analysis. Using maternal blood samples collected from expectant mothers carrying a single fetus, the cTB-derived aCGH data were able to detect fetal genders and chromosomal aberrations, which had been confirmed by standard clinical practice. Our results support the use of nanoVelcro microchips for cTB-based noninvasive prenatal genetic testing, which holds potential for further development toward future NIPD solution.

On the Importance of Clinical Follow-up in the Establishment of Non-Invasive Prenatal Testing (NIPT) for Laboratory Developed Tests

Non-invasive prenatal genetic testing (NIPT) is an advance in the detection of fetal chromosomal aneuploidies that analyzes cell-free DNA (cfDNA) in the blood of a pregnant woman. NIPT has quickly spread across the globe after introduction into clinical practice earlier in this decade. Virtually all professional societies currently recommend that NIPT be used as a screening test rather than a diagnostic method. Due to the extraordinarily high specificity and sensitivity, it is clearly an attractive alternative to conventional serum biochemical screening tests-the current standard of care. We performed a clinical validation study of our Laboratory Developed Test (LDT) assessing equivalency to the verifi™ test by Illumina, Inc. The method uses next generation sequencing (NGS), and features interpretation based on the calculation of normalized chromosomal values (NCV). In our assay, samples from 3334 consecutive patients which had been tested with Illumina’s verifi test, were blinded by an independent third party and retested by the method developed for the Progenity LDT to be offered in our commercial laboratory. As an additional level of validation, we sought and achieved follow up contact on 1681 of the original Illumina cases, to further independently confirm our results and theirs. In the analysis of equivalence between the two tests, 111 trisomy 21 samples, 43 trisomy 18 samples and 21 trisomy 13 samples were identified by both tests, indicating an equivalency of >99.9%. Although the results between the verifi “gold standard” test and our LDT proved identical (i.e., 100% concordance), the verifi test is not promoted by Illumina as having a 100% sensitivity and specificity. Therefore, certain discrepancies can only be appreciated by clinical follow up. In the NCV analyses, categories are created for “affected” or “suspected trisomy” based on the magnitude of the NCV value. Our findings suggest that the very few discrepancies were between the “aneuploidy suspected” categories of the verify reference standard and our LDT’s confirmed “not affected” or “affected” categories. Our conclusion is that NIPT LDTs must be validated by a process including clinical follow-up, not just equivalency to a reference testing method.

地域中核病院における非侵襲的出生前遺伝的検査（NIPT）の導入と高齢妊婦の出生前診断需要

地域中核病院における非侵襲的出生前遺伝的検査（NIPT）の導入と高齢妊婦の出生前診断需要

Expanding the phenotype of Triple X syndrome: A comparison of prenatal versus postnatal diagnosis.

Triple X syndrome (47, XXX) occurs in approximately 1:1,000 female births and has a variable phenotype of physical and psychological features. Prenatal diagnosis rates of 47, XXX are increasing due to non-invasive prenatal genetic testing. Previous studies suggest that prenatal diagnosed females have better neurodevelopmental outcomes. This cross-sectional study describes diagnosis, physical features, medical problems, and neurodevelopmental features in a large cohort of females with 47, XXX. Evaluation included review of medical and developmental history, physical exam, cognitive, and adaptive testing. Medical and developmental features were compared between the prenatal and postnatal diagnosis groups using rate calculations and Fisher's exact test. Cognitive and adaptive tests scores were compared using t-tests. Seventy-four females age 6 months-24 years (mean 8.3 years) participated. Forty-four (59.5%) females were in the prenatal diagnosis group. Mean age of postnatal diagnosis was 5.9 years; developmental delay was the most common indication for postnatal genetic testing. Common physical features included hypertelorism, epicanthal folds, clinodactyly, and hypotonia. Medical problems included dental disorders (44.4%), seizure disorders (16.2%), genitourinary malformations (12.2%). The prenatal diagnosis group had higher verbal (P < 0.001), general ability index (P = 0.004), and adaptive functioning scores (P < 0.001). Rates of ADHD (52.2% vs. 45.5%, P = 0.77) and learning disabilities (39.1% vs. 36.3%, P = 1.00) were similar between the two groups. These findings expand on the phenotypic features in females with Triple X syndrome and support that prenatally ascertained females have better cognitive and functional outcomes. However, prenatally diagnosed females are still at risk for neurodevelopmental disorders. Genetic counseling and treatment recommendations are summarized. © 2016 Wiley Periodicals, Inc.