Evaluation of Fetal Central Nervous System Anomalies by Ultrasound and Its Anatomical Co-relation

Genetic etiology and pregnancy outcomes of fetuses with central nervous system anomalies

PURPOSE

To investigate genetic etiology and pregnancy outcomes of fetal central nervous system (CNS) anomalies.

METHODS

217 fetuses with CNS anomalies were included in our cohort from January 2016 to December 2022. 124 cases received karyotyping and 73 cases simultaneously underwent copy number variant sequencing (CNV-seq). Dynamic ultrasound screening and pregnancy outcomes were followed up, including neonates' neurodevelopmental outcomes.

RESULTS

(1) 20 types of CNS anomalies were revealed by ultrasound and the most common was ventriculomegaly. (2) 14 (11.3%) of 124 cases were found chromosomal abnormalities by karyotyping, and copy number variations (CNVs) were revealed in 13 (17.8%) of 73 cases by CNV-seq. Fetuses with non-isolated CNS anomalies had a higher detection rate (DR) of abnormal karyotypes and CNVs than those with isolated CNS anomalies (25.0% vs. 4.8%; 35.0% vs. 11.3%) (P < 0.05). And the DR of abnormal karyotypes was significantly higher in multiple CNS anomalies than in single CNS anomaly (16.7% vs. 2.8%, P < 0.05), while there were no significant differences in the DR of CNVs. (3) Through dynamic ultrasound, 12 cases were further found progression or additional malformations. (4) Pregnancy outcomes of 209 cases were obtained, including 136 (65.1%) live births, 3 (1.4%) intrauterine fetal deaths, and 70 (33.5%) terminated. Two neonatal deaths at 6 months and one infant with motor and intellectual disabilities were finally found after long-term follow-up.

CONCLUSION

Genetic analysis combined with dynamic ultrasound screening and multidisciplinary consultation plays an important role in evaluating the prognosis of fetal CNS anomalies, especially for those with multiple CNS or extracranial abnormalities.

Monogenic conditions and central nervous system anomalies: A prospective study, systematic review and meta-analysis

OBJECTIVES

Determine the incremental diagnostic yield of prenatal exome sequencing (pES) over chromosome microarray (CMA) or G-banding karyotype in fetuses with central nervous system (CNS) abnormalities.

METHODS

Data were collected via electronic searches from January 2010 to April 2022 in MEDLINE, Cochrane, Web of Science and EMBASE. The NHS England prenatal exome cohort was also included. Incremental yield was calculated as a pooled value using a random-effects model.

RESULTS

Thirty studies were included (n = 1583 cases). The incremental yield with pES for any CNS anomaly was 32% [95%CI 27%-36%; I2 = 72%]. Subgroup analysis revealed apparent incremental yields in; (a) isolated CNS anomalies; 27% [95%CI 19%-34%; I2 = 74%]; (b) single CNS anomaly; 16% [95% CI 10%-23%; I2 = 41%]; (c) more than one CNS anomaly; 31% [95% Cl 21%-40%; I2 = 56%]; and (d) the anatomical subtype with the most optimal yield was Type 1 malformation of cortical development, related to abnormal cell proliferation or apoptosis, incorporating microcephalies, megalencephalies and dysplasia; 40% (22%-57%; I2 = 68%). The commonest syndromes in isolated cases were Lissencephaly 3 and X-linked hydrocephalus.

CONCLUSIONS

Prenatal exome sequencing provides a high incremental diagnostic yield in fetuses with CNS abnormalities with optimal yields in cases with multiple CNS anomalies, particularly those affecting the midline, posterior fossa and cortex.

Application of Single Nucleotide Polymorphism Microarray in Prenatal Diagnosis of Fetuses with Central Nervous System Abnormalities

Background

The current gold standard of karyotype analysis for prenatal diagnosis of fetuses with central nervous system (CNS) abnormalities has some limitations. Here, we assessed the value of single nucleotide polymorphism (SNP) arrays as a diagnostic tool.

Methods

The results of prenatal diagnosis of 344 fetuses with CNS abnormalities as determined by ultrasonographic screening were retrospectively analyzed. All fetuses underwent chromosomal karyotype analysis and genome-wide SNP array analysis simultaneously. The resultant rates and frequencies of genomic abnormalities were compared.

Results

Karyotype analysis found 45 (13.2%) abnormal CNS cases, while SNP array found 60 (17.4%) cases. SNP array detected 23 (6.7%) cases of submicroscopic abnormalities that karyotype analysis did not find. The detection rate of karyotype analysis was 8.1% in the group with isolated CNS anomalies, but 16.5% in the group with CNS abnormalities plus extra ultrasound anomalies. Detection rates of SNP array were 12.4% and 20.8% in these two groups, respectively. Statistical analysis showed that the detection rates of both methods were significantly higher in the group with CNS malformations and other ultrasound anomalies than in the group with isolated CNS anomalies. Abnormal chromosomes were detected most frequently in fetuses with holoprosencephaly.

Conclusion

Genome-wide SNP array technology can significantly improve the positive detection rate of fetuses with CNS abnormalities. Combining karyotype analysis and SNP array technology is recommended for detecting the development of fetuses with abnormal CNS.

Clinical Utility and the Yield of Single Nucleotide Polymorphism Array in Prenatal Diagnosis of Fetal Central Nervous System Abnormalities

Applying single nucleotide polymorphism (SNP) array to identify the etiology of fetal central nervous system (CNS) abnormality, and exploring its association with chromosomal abnormalities, copy number variations, and obstetrical outcome. 535 fetuses with CNS abnormalities were analyzed using karyotype analysis and SNP array. Among the 535 fetuses with CNS abnormalities, chromosomal abnormalities were detected in 36 (6.7%) of the fetuses, which were consistent with karyotype analysis. Further, additional 41 fetuses with abnormal copy number variations (CNVs) were detected using SNP array (the detection rate of additional abnormal CNVs was 7.7%). The rate of chromosomal abnormalities, but not that of pathogenic CNVs in CNS abnormalities with other ultrasound abnormalities was significantly higher than that in isolated CNS abnormalities. The rates of chromosomal abnormalities and pathogenic CNVs in fetuses with spine malformation (50%), encephalocele (50%), subependymal cyst (20%), and microcephaly (16.7%) were higher than those with other isolated CNS abnormalities. The pregnancies for 36 cases with chromosomal abnormalities, 18 cases with pathogenic CNVs, and three cases with VUS CNVs were terminated. SNP array should be used in the prenatal diagnosis of fetuses with CNS abnormalities, which can enable better prenatal assessment and genetic counseling, and affect obstetrical outcomes.

Microsomic and macrosomic body structure in children and adolescents affected by syndromes or diseases associated with neurodysfunction

In Poland the issue of microsomic body structure (micro-SBS) and macrosomic body structure (macro-SBS) has so far been overlooked. Up until now only a small amount of data have been published, most often as an overview of the problem. The current study was designed to investigate the co-occurrence of microsomic/macrosomic body structure (micro/macro-SBS) and congenital nervous system disorders or neurological syndromes with symptoms visible from infancy, based on essential data acquired during admission procedures at a neurological rehabilitation ward for children and adolescents. The study applied a retrospective analysis of data collected during hospitalization of 327 children and adolescents, aged 4-18 years who had been affected since infancy by congenital disorders of the nervous system and/or neurological syndromes associated with a minimum of one neurodysfunction. To identify subjects with microsomic or macrosomic body structure in the group of children and adolescents, the adopted criteria took into account z-score values for body height (z-score Ht), body weight (z-score Wt), head circumference (z-score HC), BMI (z-score BMI) and head circumference index (z-score HCI). The rates of micro/macro-SBS in the study group amounted to 7.3% and 0.6%, respectively. The findings show a more frequent co-occurrence of, as well as statistically significant correlations between, micro/macro-SBS and type of spasticity (cerebral palsy) (p = 0.024) as well as hydrocephalus not treated surgically (p < 0.001). Macro-SBS was found to more frequently co-occur with hemiplegia and hydrocephalus not treated surgically.

Detection of submicroscopic chromosomal aberrations by chromosomal microarray analysis for the prenatal diagnosis of central nervous system abnormalities

Background

Central nervous system (CNS) abnormalities are a group of serious birth defects associated with high rates of stillbirths, infant death, or abnormal development, and various disease‐causing copy number variations play a much more important role in the etiology of CNS abnormalities. This study intends to present a retrospective study of the prenatal diagnosis and the pregnancy outcome of fetuses diagnosed with CNS abnormalities, and evaluate the clinical value of chromosomal microarray analysis (CMA) in prenatal diagnosis of CNS abnormalities.

Methods

A total of 356 fetuses with CNS abnormalities with or without other ultrasound abnormalities subjected to invasive prenatal diagnosis at the first affiliated hospital of Air Force Medical University from January 2015 to August 2018. All cases have performed both karyotyping and CMA concurrently, but 20 fetuses with chromosome aneuploidy were excluded in the current study.

Results

The CMA identified pathogenic copy number variants (pCNVs) in 27/336 (8.03%) fetuses, likely pCNVs in 8/336 (2.38%) fetuses, and variants of unknown significance (VOUS) in 11/336 (3.27%) fetuses. A total of 222 cases had single CNS abnormalities and the pCNVs detection rate was 5.86% (13/222), the remaining 114 cases including CNS abnormalities plus other structural abnormalities, ultrasonographic soft markers and two or more CNS abnormalities, the pCNVs detection rate was 12.3% (14/114).

Conclusions

Fetuses with CNS abnormalities have a higher risk of chromosomal abnormalities, our study showed that CNVs play an important role in the etiology of CNS abnormalities. The application of CMA could increase the detection rate of pCNVs causing CNS abnormalities.

A metabolomics-based approach for non-invasive screening of fetal central nervous system anomalies

BACKGROUND

Central nervous system anomalies represent a wide range of congenital birth defects, with an incidence of approximately 1% of all births. They are currently diagnosed using ultrasound evaluation. However, there is strong need for a more accurate and less operator-dependent screening method.

OBJECTIVES

To perform a characterization of maternal serum in order to build a metabolomic fingerprint resulting from congenital anomalies of the central nervous system.

METHODS

This is a case-control pilot study. Metabolomic profiles were obtained from serum of 168 mothers (98 controls and 70 cases), using gas chromatography coupled to mass spectrometry. Nine machine learning and classification models were built and optimized. An ensemble model was built based on results from the individual models. All samples were randomly divided into two groups. One was used as training set, the other one for diagnostic performance assessment.

RESULTS

Ensemble machine learning model correctly classified all cases and controls. Propanoic, lactic, gluconic, benzoic, oxalic, 2-hydroxy-3-methylbutyric, acetic, lauric, myristic and stearic acid and myo-inositol and mannose were selected as the most relevant metabolites in class separation.

CONCLUSION

The metabolomic signature of second trimester maternal serum from pregnancies affected by a fetal central nervous system anomaly is quantifiably different from that of a normal pregnancy. Maternal serum metabolomics is therefore a promising tool for the accurate and sensitive screening of such congenital defects. Moreover, the details of the most relevant metabolites and their respective biochemical pathways allow better understanding of the overall pathophysiology of affected pregnancies.

Conventional Chromosome Analysis of Fetuses with Central Nervous System Anomalies and Associated Anomalies: Is Anything Changed?

Central nervous system (CNS) abnormalities are often isolated but can accompany various genetic syndromes. In this study, we evaluated conventional karyotype results and associated findings of fetuses that were diagnosed with CNS abnormalities. Cases included in the study were diagnosed with fetal CNS anomalies and underwent conventional karyotyping. Conventional karyotype results of subjects were compared with karyotype results of fetal karyotyped patients as a result of maternal anxiety in a two-year period. In this period, 69 patients were diagnosed with fetal CNS anomalies and 64 of them underwent invasive fetal karyotyping. Of these, 32 patients had isolated CNS anomalies, while 32 were associated with other anomalies. There was no significant difference between karyotype results when compared with the control group (p = 0.76). Apart from some specific anomalies, the aneuploidy rate does not significantly differ between fetuses with CNS anomalies and the control group. Advanced genetic evaluation may provide additional diagnostic benefits, especially for this group.

Prenatal Diagnosis of Central Nervous System Anomalies by High-Resolution Chromosomal Microarray Analysis

The aims of this study were to evaluate the contribution of chromosomal microarray analysis (CMA) in the prenatal diagnosis of fetuses with central nervous system (CNS) anomalies but normal chromosomal karyotype. A total of 46 fetuses with CNS anomalies with or without other ultrasound anomalies but normal karyotypes were evaluated by array-based comparative genomic hybridisation (aCGH) or single-nucleotide polymorphism (SNP) array. The result showed that CNVs were detected in 17 (37.0%) fetuses. Of these, CNVs identified in 5 (5/46, 10.9%) fetuses were considered to be likely pathogenic, and CNVs detected in 3 (3/46, 6.5%) fetuses were defined as being of uncertain clinical significance. Fetuses with CNS malformations plus other ultrasound anomalies had a higher rate of pathogenic CNVs than those with isolated CNS anomalies (13.6% versus 8.3%), but there was no significant difference (Fisher's exact test, P > 0.05). Pathogenic CNVs were detected most frequently in fetuses with Dandy-Walker syndrome (2/6, 33.3%) when compared with other types of neural malformations, and holoprosencephaly (2/7, 28.6%) ranked the second. CMA is valuable in prenatal genetic diagnosis of fetuses with CNS anomalies. It should be considered as part of prenatal diagnosis in fetuses with CNS malformations and normal karyotypes.

Evaluation and prevalence of major central nervous system malformations: a retrospective study

OBJECTIVE:

Central nervous system (CNS) anomalies are the most common abnormalities of all malformations and can be diagnosed on routine prenatal ultrasonography (US). We aimed to find out fetal CNS anomaly rate in our clinic which is the referral center in the region.

METHODS:

This is a retrospective study of 15000 pregnant women who were scanned for routine obstetric follow-up from January 2012 to July 2013 in our referral center. We diagnosed CNS anomalies in 41 fetuses by using high resolution ultrasound unit with 3.5 MHz transabdominal and 6 MHz transvaginal transducers.

RESULTS:

CNS anomalies included 12 Chiari malformations, 2 Dandy-Walker malformations (DWM), 1 variant of Dandy-Walker syndrome (DWS), 3 iniencephalies, 15 anencephalies, 1 alobar holoprosencephaly, 2 isolated hydrocephalies, 3 hydrocephalies with cerebellar hypoplasia, 1 occipital encephalocele, 1 lumbosacral myelomeningocele accompanied with microcephaly. There were some associated anomalies in the groups that included club-foot deformities in 6 cases, ventricular septal defect (VSD) in 2 cases, polycystic kidney in 2 cases, scoliosis in 1 case, hypoplasic left ventricle in 1 case; alone atrium, single umbilical artery, echogenic focus, hydronephrosis and cleft lip and palate in the same case, and omphalocele in one.

CONCLUSION:

Prognosis and early detection of CNS abnormalities have become an important issue because the most serious complications of major CNS anomalies are disability and getting bedridden and this situation is inevitably related to health economy. On the other hand prognosis of the fetus and family counseling is another important issue. Parents should decide whether to continue their pregnancies or not.