Prognostic indicators in the prenatal diagnosis of agenesis of corpus callosum

Fetal MRI Analysis of Corpus Callosal Abnormalities: Classification, and Associated Anomalies

BACKGROUND

Corpus callosal abnormalities (CCA) are midline developmental brain malformations and are usually associated with a wide spectrum of other neurological and non-neurological abnormalities. The study aims to highlight the diagnostic role of fetal MRI to characterize heterogeneous corpus callosal abnormalities using the latest classification system. It also helps to identify associated anomalies, which have prognostic implications for the postnatal outcome.

METHODS

In this study, retrospective data from antenatal women who underwent fetal MRI between January 2014 and July 2023 at Rush University Medical Center were evaluated for CCA and classified based on structural morphology. Patients were further assessed for associated neurological and non-neurological anomalies.

RESULTS

The most frequent class of CCA was complete agenesis (79.1%), followed by hypoplasia (12.5%), dysplasia (4.2%), and hypoplasia with dysplasia (4.2%). Among them, 17% had isolated CCA, while the majority (83%) had complex forms of CCA associated with other CNS and non-CNS anomalies. Out of the complex CCA cases, 58% were associated with other CNS anomalies, while 8% were associated with non-CNS anomalies. 17% of cases had both.

CONCLUSION

The use of fetal MRI is valuable in the classification of abnormalities of the corpus callosum after the confirmation of a suspected diagnosis on prenatal ultrasound. This technique is an invaluable method for distinguishing between isolated and complex forms of CCA, especially in cases of apparent isolated CCA. The use of diffusion-weighted imaging or diffusion tensor imaging in fetal neuroimaging is expected to provide further insights into white matter abnormalities in fetuses diagnosed with CCA in the future.

Neuropsychological functions in a pediatric case of partial agenesis of the corpus callosum: Clinical implications

The corpus callosum (CC) is involved in several cognitive processes and the interhemispheric transfer of information. The current case study investigated neurocognitive and emotional processes in a 7-year-old female with partial agenesis of the corpus callosum, with an absent splenium and posterior body, with comorbid autism and ADHD. We measured cognitive functions, such as response inhibition, error monitoring, attentional disengagement, and attention capture by irrelevant emotional stimuli. We found that response inhibition was intact in the case. When happy faces were used as stop-signals, it interfered with response inhibition compared to angry-face-stop-signals. Similarly, happy faces (relative to angry faces) interfered with error monitoring; irrelevant angry faces captured attention more than happy faces. Attentional disengagement functions were impaired in the case compared to healthy controls. The findings give an insight into the interaction between cognition and emotion in pediatric partial agenesis of the CC, and have important clinical and theoretical implications.

Prenatal genetic testing in 19 fetuses with corpus callosum abnormality

Background

Corpus callosum abnormality (CCA) can lead to epilepsy, moderate severe neurologic or mental retardation. The prognosis of CCA is closely related to genetic etiology. However, copy number variations (CNVs) associated with fetal CCA are still limited and need to be further identified. Only a few scattered cases have been reported to diagnose CCA by whole exome sequencing (WES).

Methods

Karyotyping analysis, copy number variation sequencing (CNV‐seq), chromosomal microarray analysis (CMA) and WES were parallelly performed for prenatal diagnosis of 19 CCA cases.

Results

The total detection rate of karyotyping analysis, CMA (or CNV‐seq) and WES were 15.79% (3/19), 21.05% (4/19) and 40.00% (2/5), respectively. Two cases (case 11 and case 15) were diagnosed as aneuploidy (47, XY, + 13 and 47, XX, + 21) by karyotyping analysis and CNV‐seq. Karyotyping analysis revealed an unknown origin fragment (46,XY,add(13)(p11.2)) in case 3, which was further confirmed to originate from p13.3p11.2 of chromosome 17 by CNV‐seq. CMA revealed arr1q43q44 (238923617–246964774) × 1(8.04 Mb) in case 8 with a negative result of chromosome karyotype. WES revealed that 2 of 5 cases with negative results of karyotyping and CNV‐seq or CMA carried pathogenic genes ALDH7A1 and ARID1B.

Conclusion

Parallel genetic tests showed that CNV‐seq and CMA are able to identify additional, clinically significant cytogenetic information of CCA compared to karyotyping; WES significantly improves the detection rate of genetic etiology of CCA. For the patients with a negative results of CNV‐seq or CMA, further WES test is recommended.

Improved neurodevelopmental prognostication in isolated corpus callosal agenesis: fetal magnetic resonance imaging-based scoring system

OBJECTIVES

Corpus callosal agenesis (CCA) is one of the most common brain malformations and is generally associated with a good outcome when isolated. However, up to 25% of patients are at risk of neurodevelopmental delay, which currently available clinical and imaging parameters are inadequate to predict. The objectives of this study were to apply and validate a fetal magnetic resonance imaging (MRI) anatomical scoring system in a cohort of fetuses with isolated CCA and to evaluate the correlation with postnatal neurodevelopmental outcome.

METHODS

This was a retrospective cohort study of cases of prenatally diagnosed isolated CCA (as determined on ultrasound and MRI), with normal karyotype and with known postnatal neurodevelopmental outcome assessed by standardized testing. A fetal brain MRI anatomical scoring system based on seven categories (gyration, opercularization, temporal lobe symmetry, lamination, hippocampal position, basal ganglia and ventricular size) was developed and applied to the cohort; a total score of 0-11 points could be given, with a score of 0 representing normal anatomy. Images were scored independently by two neuroradiologists blinded to the outcome. For the purpose of assessing the correlation between fetal MRI score and neurodevelopmental outcome, neurodevelopmental test results were scored as follows: 0, 'below average' (poor outcome); 1, 'average'; and 2, 'above average' (good outcome). Spearman's rank coefficient was used to assess correlation, and inter-rater agreement in the assessment of fetal MRI score was calculated.

RESULTS

Twenty-one children (nine females (42.9%)) fulfilled the inclusion criteria. Thirty-seven fetal MRI examinations were evaluated. Mean gestational age was 28.3 ± 4.7 weeks (range, 20-38 weeks). All fetuses were delivered after 35 weeks' gestation with no perinatal complications. Fetal MRI scores ranged from 0 to 6 points, with a median of 3 points. Inter-rater agreement in fetal MRI score assessment was excellent (intraclass correlation coefficient, 0.959 (95% CI, 0.921-0.979)). Neurodevelopmental evaluation was performed on average at 2.6 ± 1.46 years (range, 0.5-5.8 years). There was a significant negative correlation between fetal MRI score and neurodevelopmental outcome score in the three areas tested: cognitive (ρ = -0.559, P < 0.0001); motor (ρ = -0.414, P = 0.012) and language (ρ = -0.565, P < 0.0001) skills. Using fetal MRI score cut-offs of ≤ 3 (good outcome) and ≥ 4 points (high risk for poor outcome), the correct prognosis could be determined in 20/21 (95.2% (95% CI, 77.3-99.2%)) cases.

CONCLUSION

By assessing structural features of the fetal brain on MRI, it may be possible to better stratify prenatally the risk of poor neurodevelopmental outcome in CCA patients. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal US and MRI in detection of craniospinal anomalies with postnatal correlation: single-center experience

Background/aim

To reveal the contribution of magnetic resonance imaging (MRI) to ultrasound (US) in prenatal diagnosis of fetal craniospinal anomalies by retrospectively comparing the prenatal and postnatal findings.

Materials and methods

After institutional review board approval, between January 2010 and May 2020, 301 pregnant women, which had a gestational age between 19–37 weeks (mean 26.5 ± 6.1 weeks), diagnosed with cranial and spinal anomalies on fetal US and later on imaged with MRI were evaluated, and in 179 of those cases prenatal imaging findings were compared with postnatal findings.

Results

A total of 191 fetal craniospinal anomalies were detected in 179 pregnant women. MRI and US diagnosis were completely correct in 145 (75.9%) and 112 (58.6%), respectively. Diagnostic performance of MRI was significantly higher than that of the US (p < 0.05). Both prenatal MRI and US findings were concordant with postnatal diagnosis in 53% of the cases. In 28.7% cases, prenatal MRI contributed to US by either changing the wrong US diagnosis (8.9%), demonstration of additional findings (14%), or confirming the suspicious US diagnosis (5.8%).

Conclusion

Due to its high resolution and multiplanar imaging capability, fetal MRI contributes significantly to US in the correct prenatal diagnosis of craniospinal anomalies. This contribution especially is significant in neural tube defects, cortical malformations, and ischemic-hemorrhagic lesions.

Beyond Isolated and Associated: A Novel Fetal MR Imaging-Based Scoring System Helps in the Prenatal Prognostication of Callosal Agenesis

BACKGROUND AND PURPOSE

Although "corpus callosum agenesis" is an umbrella term for multiple entities, prenatal counseling is based reductively on the presence (associated) or absence (isolated) of additional abnormalities. Our aim was to test the applicability of a fetal MR neuroimaging score in a cohort of fetuses with prenatally diagnosed isolated corpus callosum agenesis and associated corpus callosum agenesis and correlate it with neurodevelopmental outcomes.

MATERIALS AND METHODS

We performed a single-center retrospective analysis of a cohort of cases of consecutive corpus callosum agenesis collected between January 2011 and July 2019. Cases were scored by 2 raters, and interater agreement was calculated. Outcome was assessed by standardized testing (Bayley Scales of Infant and Toddler Development, Kaufman Assessment Battery for Children) or a structured telephone interview and correlated with scores using 2-way ANOVA.

RESULTS

We included 137 cases (74 cases of isolated corpus callosum agenesis), imaged at a mean of 27 gestational weeks. Interrater agreement was excellent (0.98). Scores were higher in associated corpus callosum agenesis (P < .0001) without a significant score difference between complete and partial corpus callosum agenesis (P = .38). Outcome was assessed in 42 children with isolated corpus callosum agenesis and 9 with associated corpus callosum agenesis (mean age, 3.1 years). MR imaging scores correctly predicted developmental outcome in 90.7% of patients with isolated corpus callosum agenesis, improving neurodevelopmental risk stratification in corpus callosum agenesis.

CONCLUSIONS

The scoring system is very reproducible and can differentiate isolated corpus callosum agenesis and associated isolated corpus callosum agenesis (significantly higher scores) but not between partial and complete corpus callosum agenesis. Scores correlated with outcome in isolated corpus callosum agenesis, but there were too few associated postnatal cases of isolated corpus callosum agenesis to draw conclusions in this group.

Ultrasound Measurements of Frontal Horns and the Cavum Septi Pellucidi in Healthy Fetuses in the Second and Third Trimesters of Pregnancy

OBJECTIVES

To assess the visualization rate and size of the frontal horns (FHs) and cavum septi pellucidi (CSP) in healthy fetuses throughout pregnancy.

METHODS

After Institutional Review Board approval, 522 consecutive uncomplicated singleton pregnancies between 15 and 39 gestational weeks were enrolled in the study. Ultrasound measurements of the anterior horn width (AHW), center from the horn distance (CFHD), distance from the FHs to the CSP, and CSP width were retrospectively performed using axial transventricular or transcerebellar planes. Available maternal body mass indices were recorded.

RESULTS

At least 1 FH was seen in 78% of the cases. The mean AHW decreased over the second trimester and plateaued in the third trimester. The CFHD plateaued in the second trimester and increased in the third trimester. Downside FHs were generally larger than upside FHs. More FHs were measured in transventricular (69%) than transcerebellar (31%) planes. Frontal horns were seen with high, low, and no confidence in 57%, 21%, and 22% of cases, respectively. No-confidence rates were 17% in the second trimester and 42% in the third trimester. The CSP was not visualized in 4% of cases; 15 of 19 cases of a nonvisualized CSP were scanned between 18 and 37 weeks. Mean body mass indices ± SDs were 27.6 ± 6.7 kg/m² for the patients in cases of a visualized CSP and 32.4 ± 9.1 kg/m² for the patients in cases of a nonvisualized CSP.

CONCLUSIONS

Normative data for the fetal FH and CSP width were established. Frontal horns are more frequently seen on transventricular views and are difficult to confidently assess in the late third trimester. This study challenges previously reported data that the CSP is seen in 100% of cases from 18 to 37 weeks.

A Neuropsychological Profile for Agenesis of the Corpus Callosum? Cognitive, Academic, Executive, Social, and Behavioral Functioning in School-Age Children

OBJECTIVES

Agenesis of the corpus callosum (AgCC), characterized by developmental absence of the corpus callosum, is one of the most common congenital brain malformations. To date, there are limited data on the neuropsychological consequences of AgCC and factors that modulate different outcomes, especially in children. This study aimed to describe general intellectual, academic, executive, social and behavioral functioning in a cohort of school-aged children presenting for clinical services to a hospital and diagnosed with AgCC. The influences of age, social risk and neurological factors were examined.

METHODS

Twenty-eight school-aged children (8 to 17 years) diagnosed with AgCC completed tests of general intelligence (IQ) and academic functioning. Executive, social and behavioral functioning in daily life, and social risk, were estimated from parent and teacher rated questionnaires. MRI findings reviewed by a pediatric neurologist confirmed diagnosis and identified brain characteristics. Clinical details including the presence of epilepsy and diagnosed genetic condition were obtained from medical records.

RESULTS

In our cohort, ~50% of children experienced general intellectual, academic, executive, social and/or behavioral difficulties and ~20% were functioning at a level comparable to typically developing children. Social risk was important for understanding variability in neuropsychological outcomes. Brain anomalies and complete AgCC were associated with lower mathematics performance and poorer executive functioning.

CONCLUSIONS

This is the first comprehensive report of general intellectual, academic, executive social and behavioral consequences of AgCC in school-aged children. The findings have important clinical implications, suggesting that support to families and targeted intervention could promote positive neuropsychological functioning in children with AgCC who come to clinical attention. (JINS, 2018, 24, 445-455).

Agenesis of the corpus callosum, developmental delay, autism spectrum disorder, facial dysmorphism, and posterior polymorphous corneal dystrophy associated with ZEB1 gene deletion

We report on a girl diagnosed prenatally with agenesis of the corpus callosum (ACC) on fetal ultrasound and MRI. On postnatal follow-up she was noted to have developmental delay, facial dysmorphism, autism spectrum disorder, and posterior polymorphous corneal dystrophy (PPD). Array-comparative genomic hybridization analysis (Array-CGH) showed a 2.05 Mb de novo interstitial deletion at 10p11.23p11.22. The deleted region overlaps 1 OMIM Morbid Map gene, ZEB1 (the zinc finger E-box binding homeobox transcription factor 1), previously associated with posterior polymorphous corneal dystrophy type 3 (PPCD3). To our best knowledge this is the first reported case with a deletion of the ZEB1 gene in an individual with ACC and PPD, showing that the haploinsufficiency of the ZEB1 is likely the cause of our patient's phenotype.

Clinical outcomes and neurodevelopmental outcome of prenatally diagnosed agenesis of corpus callosum in single center of Korea

OBJECTIVE

With recent advances and frequent use of prenatal ultrasound, the antenatal diagnosis of agenesis of the corpus callosum (ACC) is not rare in obstetrics practices. However, information regarding the long-term neurological outcome remains uncertain. The aim of this study was to investigate clinical outcomes of prenatally diagnosed ACC and to analyze postnatal neurodevelopmental outcomes of ACC neonates born in our single center.

METHODS

We retrospectively reviewed 56 cases of prenatally suspected ACC referred to our center.

RESULTS

Fifty-six fetuses were diagnosed with ACC, and 12 of those were followed-up in our center until delivery. Of the remaining 44, 7 were delivered after being referred back to the original hospital, 23 were lost to follow-up, and 14 had unknown outcomes. Among all 56, 29 were considered to have isolated ACC and 27 were considered to have non-isolated ACC. Of the 10 live fetuses delivered in our center, four had isolated ACC, three had non-isolated ACC, and the rest had outcomes unrelated to ACC. Neurodevelopmental outcome was followed-up until approximately age 3 years. Of the four with isolated ACC, three (75%) had normal neurodevelopmental outcomes.

CONCLUSION

Similar to other studies, the results of our single-center study included positive neurodevelopmental outcomes for those with isolated ACC. However, despite our endeavor to counsel patients with prenatally diagnosed ACC, the delivery rate in our center was quite low. Therefore, larger, multicenter, retrospective studies including long-term neurological development outcomes are crucial and urgently needed to provide better counseling.

What Is the Rate of Incomplete Fetal Anatomic Surveys During a Second-Trimester Scan? Retrospective Observational Study of 4000 Nonobese Pregnant Women

OBJECTIVES

The purpose of this study was to estimate the rate of incomplete fetal anatomic surveys during a second-trimester scan due to an unfavorable fetal position in a nonobese population.

METHODS

All pregnant women who came to the Altamedica Fetal-Maternal Medical Center, a specialized center for prenatal diagnosis, for a routine second-trimester scan between January 2012 and April 2013 were retrospectively included in the analysis. Patients with a body mass index higher than 30.0 kg/m(2) or anterior fibroids larger than 5 cm were not included in the study.

RESULTS

Of 4000 pregnant women admitted for a second-trimester scan, 169 (4.2%) came back within 2 weeks to complete the examination because of an unfavorable fetal position. In particular, 104 (2.6%) needed visualization of only 1 view, and 65 (1.6%) needed more than 1 view. The most difficult organ to visualize was the corpus callosum, in 73 cases (1.8%); the face was not visualized in 69 cases (1.7%); the cerebellar vermis was not seen in 47 fetuses (1.1%); and the heart could not be completely examined in 40 fetuses (1.0%). Of the 4000 women, 169 (4.2%) had a nonexhaustive scan; 149 (3.7%) needed a second scan to complete the second-trimester survey; 14 (0.35%) needed a third scan; and 2 (0.05%) remained with a not completely exhaustive scan.

CONCLUSIONS

There is always a small percentage of incomplete fetal anatomic surveys during a second-trimester scan, which cannot be modified by the sonographer's skill or by technical sonographic innovations.

Disrupted developmental organization of the structural connectome in fetuses with corpus callosum agenesis

Agenesis of the corpus callosum is a model disease for disrupted connectivity of the human brain, in which the pathological formation of interhemispheric fibers results in subtle to severe cognitive deficits. Postnatal studies suggest that the characteristic abnormal pathways in this pathology are compensatory structures that emerge via neural plasticity. We challenge this hypothesis and assume a globally different network organization of the structural interconnections already in the fetal acallosal brain. Twenty fetuses with isolated corpus callosum agenesis with or without associated malformations were enrolled and fiber connectivity among 90 brain regions was assessed using in utero diffusion tensor imaging and streamline tractography. Macroscopic scale connectomes were compared to 20 gestational age-matched normally developing fetuses with multiple granularity of network analysis. Gradually increasing connectivity strength and tract diffusion anisotropy during gestation were dominant in antero-posteriorly running paramedian and antero-laterally running aberrant pathways, and in short-range connections in the temporoparietal regions. In fetuses with associated abnormalities, more diffuse reduction of cortico-cortical and cortico-subcortical connectivity was observed than in cases with isolated callosal agenesis. The global organization of anatomical networks consisted of less segregated nodes in acallosal brains, and hubs of dense connectivity, such as the thalamus and cingulate cortex, showed reduced network centrality. Acallosal fetal brains show a globally altered connectivity network structure compared to normals. Besides the previously described Probst and sigmoid bundles, we revealed a prenatally differently organized macroconnectome, dominated by increased connectivity. These findings provide evidence that abnormal pathways are already present during at early stages of fetal brain development in the majority of cerebral white matter.

Antenatal diagnosis of agenesis of the corpus callosum

AIM

To estimate the diagnostic performance of ultrasound in detecting agenesis of the corpus callosum (ACC).

MATERIALS AND METHODS

A retrospective review was performed of 1722 in utero MRI examinations. All cases were identified in which the fetus had been referred from ultrasonography with a diagnosis of ACC and those in which ACC was given as a diagnosis on the in utero MRI study. The MRI was assumed to provide the correct diagnosis of ACC and descriptive statistics of diagnostic accuracy for ultrasound were calculated.

RESULTS

Of the 1722 ultrasound examinations performed, 121 had a diagnosis of ACC and approximately 50% were confirmed at MRI. Forty-two fetuses with ACC not suspected at ultrasonography were also identified at MRI. Ultrasonography had a positive predictive value of 47% (95% CI: 38-56%) and a negative predictive value of 97% (95% CI: 96-98%) for detecting ACC.

CONCLUSION

Ultrasound is poor in diagnosing ACC and in utero MRI should be performed if there is any suspicion on antenatal ultrasonography.

Reference charts for fetal corpus callosum length: a prospective cross-sectional study of 2950 fetuses

OBJECTIVES

The purpose of this study was to establish reference charts for fetal corpus callosum length in a convenience sample.

METHODS

A prospective cross-sectional study was conducted at the Artemisia Fetal-Maternal Medical Center between December 2008 and January 2012. Among 16,975 fetal biometric measurements between 19 weeks and 37 weeks 6 days' gestation, 3438 measurements of the corpus callosum (20.3%) were available. After excluding 488 measurements (14.2%), a total of 2950 fetuses (85.8%) were considered and analyzed only once. Parametric and nonparametric quantile regression models were used for the statistical analysis. To evaluate the robustness of the proposed reference charts with respect to various distributional assumptions on the sonographic measurements at hand, we compared the gestational age (GA)-specific reference curves produced by the statistical methods used.

RESULTS

The mean corpus callosum length was 26.18 mm (SD, 4.5 mm; 95% confidence interval, 26.01-26.34 mm). The linear regression equation expressing the length of the corpus callosum as a function of GA was length (mm) = -11.17 + 1.62 × GA. The correlation between the dimension and gestation was expressed by the coefficient r = 0.83. Normal mean lengths according the parametric and nonparametric methods were defined for each week of gestation.

CONCLUSIONS

This work provides new quantile-based reference charts for corpus callosum length measurements that may be useful for diagnosis of congenital corpus callosum anomalies in fetal life.

Counseling in fetal medicine: agenesis of the corpus callosum

In this Review, we aim to provide up-to-date and evidence-based answers to common questions regarding the diagnosis and prognosis of prenatally detected agenesis of the corpus callosum (ACC). A systematic literature search was performed to identify all reports of ACC and reference lists of articles were identified. ACC involves partial or complete absence of the main commissural pathway that connects the two cerebral hemispheres, and can be isolated (with no other abnormalities) or complex (coexisting with other abnormalities). It is a rare finding and the prevalence is difficult to estimate because of selection bias in reported series. The corpus callosum (CC) can be assessed on ultrasound by direct visualization, but indirect features, such as ventriculomegaly, absence of the cavum septi pellucidi or widening of interhemispheric fissure, are often the reason for detection in a screening population. Careful imaging in a center with a high level of expertise is required to make a full assessment and to exclude coexisting abnormalities, which occur in about 46% of fetuses. When available, magnetic resonance imaging appears to be an important adjunct as it allows direct visualization. It can reduce false-positive rates on ultrasound and can confirm ACC, it can assess whether this is complete or partial and it can help in detecting coexisting brain abnormalities not seen on ultrasound. The overall rate of chromosomal abnormality in fetuses with ACC is 18%, but this high rate includes both isolated and complex ACC; more recent studies suggest that chromosomal abnormalities are rare in isolated cases. Nevertheless, postnatal follow-up studies suggest that about 15% of cases thought to be isolated prenatally were found to have associated abnormalities after birth. Neurodevelopmental outcome in isolated ACC was recently reported in a systematic review and suggested normal outcome in about 65-75% of cases. Findings need to be considered in light of the several limitations of existing studies, in terms of study design, selection bias, varying definitions and imaging protocols, ascertainment bias and lack of control groups. These uncertainties mean that antenatal counseling is difficult and further large prospective studies are needed.

Callosal dysgenesis in fetuses with ventriculomegaly: levels of agreement between imaging modalities and postnatal outcome

OBJECTIVE

To assess neurodevelopmental outcome of fetuses diagnosed with callosal abnormalities after referral for ventriculomegaly.

METHODS

This sub-analysis of a prospective study of 430 fetuses, which were referred for ventriculomegaly and underwent sonography and magnetic resonance imaging (MRI), included those fetuses with a diagnosis of corpus callosal abnormalities after recruitment into the main study. Between three and six radiologists independently reviewed ultrasound and MR images and recorded central nervous system (CNS) abnormalities, with final diagnoses being decided by consensus. Postnatal outcomes of fetuses with callosal abnormalities were compared between those with and those without other abnormalities.

RESULTS

Callosal abnormalities were detected in 13% (58/430) of the fetuses referred with ventriculomegaly. Callosal dysgenesis was isolated in 24% (14/58) of these cases, with the remainder complicated by CNS, karyotypic or other major abnormalities. Five fetuses diagnosed prenatally as having isolated callosal abnormalities had additional CNS findings on postnatal assessment. Preconference kappa for callosal abnormalities was 0.76 for ultrasound and 0.78 for MRI, indicating that these investigations had a similar level of operator dependence. Neurodevelopmental outcome was normal or showed only mild delay that resolved in 67% (8/12) children with isolated callosal abnormalities compared to 7% (2/27) in those with non-isolated callosal abnormalities (P = 0.003).

CONCLUSION

Callosal abnormalities are present in a significant proportion of fetuses with a diagnosis of ventriculomegaly. Isolated callosal abnormalities are associated with normal neurodevelopmental outcome in approximately two-thirds of fetuses.

Neurodevelopment after prenatal diagnosis of isolated agenesis of the corpus callosum: an integrative review

OBJECTIVE

To systematically review published data on the neurodevelopment of children that were diagnosed prenatally with isolated agenesis of the corpus callosum.

STUDY DESIGN

Medline and Scopus searches (1960-July 2011); cross-referencing of retrieved articles.

RESULTS

Sixteen reports (132 cases of apparently isolated agenesis of the corpus callosum) were included in the analysis. The rates of normal outcome, borderline or moderate disability and severe disability were 94/132 (71.2%; 95% confidence interval [CI], 63.0-78.3), 18/132 (13.6%; 95% CI, 8.8-20.5), and 22/132 (15.2%; 95% CI, 10.0-22.2), respectively. Magnetic resonance imaging detected additional cerebral abnormalities in 22.5% (95% CI, 12.3-37.5) of apparently isolated agenesis of the corpus callosum cases. In truly isolated agenesis of the corpus callosum (confirmed by magnetic resonance imaging), the rates of normal neurodevelopment and severe disability were 52/69 (75.4%; 95% CI, 64.0-84.0) and 8/69 (11.6%; 95% CI, 6.0-21.2), respectively.

CONCLUSION

Prenatally diagnosed, isolated agenesis of the corpus callosum is usually associated with a favorable outcome. Larger, prospective series are required, as current data are limited, inconsistent, and prevent subgroup analyses (eg, complete vs partial agenesis of the corpus callosum).

Prenatal diagnosis and outcome of partial agenesis and hypoplasia of the corpus callosum

OBJECTIVE

To present antenatal sonographic findings and outcome of fetuses with hypoplasia or partial agenesis of the corpus callosum.

METHODS

The database of our ultrasound laboratory was searched retrospectively for cases of hypoplasia or partial agenesis of the corpus callosum suspected at antenatal neurosonography between 1998 and 2008 and confirmed by pathology or postnatal neuroimaging. In surviving infants, clinical follow-up had been arranged to assess neurodevelopmental outcome.

RESULTS

Nineteen fetuses with callosal underdevelopment were identified at a median gestational age of 22 (range, 21-33) weeks and confirmed at follow-up, including 14 with partial agenesis and five with hypoplasia. Among the 14 fetuses with partial agenesis, there were additional brain findings in 10, including two with absent cavum septi pellucidi, four with mild isolated ventriculomegaly and four with cerebellar abnormalities, two of which also had ventriculomegaly. Pregnancy was terminated electively in seven of the cases with partial agenesis and there was one neonatal death. Among the six surviving infants, neurodevelopmental outcome was appropriate for age in three at follow up, including two cases with isolated partial agenesis of the corpus callosum. Among the five fetuses with prenatally diagnosed callosal hypoplasia, additional anomalies were present in four. Two cases were terminated electively and three were alive at the time of writing, with a median age of 3 years. Among them, apparently normal neurological development was observed in only one case.

CONCLUSIONS

An antenatal diagnosis of callosal underdevelopment is possible by expert sonography. There is often association with other major anomalies. However, even in fetuses with apparently isolated findings, the prognosis is uncertain.

Agenesis of the corpus callosum: an MR imaging analysis of associated abnormalities in the fetus

BACKGROUND AND PURPOSE

Anomalies associated with callosal agenesis (ACC) found postnatally have been well documented. However, to our knowledge, no detailed MR imaging analysis of associated anomalies has been reported in a large cohort of fetuses with ACC. This study will assess those anomalies and compare them with postnatal cohorts of ACC, to identify associated fetal brain abnormalities that may give insight into etiology and outcome.

MATERIALS AND METHODS

All cases of ACC diagnosed on fetal MR imaging during an 11-year period were retrospectively reviewed, including fetal MR imaging, postnatal MR imaging, and autopsy findings. Neurodevelopmental outcome was classified as poor in children with seizures and/or severe neurodevelopmental impairment or in cases of neonatal death.

RESULTS

Twenty-nine cases of ACC were identified. Median gestational age was 26.14 weeks (range, 19.71-36.43 weeks). Twenty-three fetuses had delayed sulcation and/or too-numerous cortical infoldings (abnormal morphology). Fifteen fetuses had cerebellar and/or brain stem abnormalities. Fetal MR imaging findings suggested a genetic syndrome in 5 fetuses and an acquired etiology or genetic/metabolic disorder in 2 fetuses. Findings were confirmed in 8 cases with postnatal MR imaging, except for delayed sulcation and small vermis, and in 4 cases with autopsy, except for periventricular nodular heterotopia and abnormalities in areas not examined by autopsy. Neurodevelopmental outcome was good in 7 and poor in 9 children. Abnormal sulcal morphology and/or infratentorial abnormalities were present in those with poor outcome and absent in those with good outcome.

CONCLUSIONS

ACC is infrequently isolated in fetuses. Abnormal sulcation is common and suggests more diffuse white matter dysgenesis in these fetuses.

Foetal brain imaging: ultrasound or MRI. A comparison between magnetic resonance imaging and a dedicated multidisciplinary neurosonographic opinion

OBJECTIVES

(i) To compare original foetal brain ultrasound findings with a multidisciplinary expert opinion; (ii) to compare the multidisciplinary expert ultrasound opinion with foetal magnetic resonance imaging (MRI) findings and (iii) to determine in which circumstances foetal MRI gives additional information, and in how many cases management is changed by having information from MRI.

STUDY DESIGN

Ultrasound scans of 51 consecutive foetuses where foetal brain MR had been performed were retrospectively reviewed by a panel consisting of maternal-foetal-medicine (MFM) consultants, a geneticist, neonatologists and MFM subspecialty trainees. The original ultrasound opinion was compared with the multidisciplinary opinion, which was then compared with MRI findings. In the cases where MRI gave additional information, an assessment was made as to whether this changed management.

RESULTS

The multidisciplinary ultrasound opinion differed from the original opinion in 9 of 51 (17%) cases. In 19 patients (37%), the MRI gave additional information to the original ultrasound, in 7 (13%) cases, management, and in 7 (13%) cases, counselling was altered by additional information gained from MRI. The multidisciplinary ultrasound and MRI diagnoses were similar in 36 cases (71%).

CONCLUSION

Multidisciplinary review of an apparently abnormal foetal brain ultrasound can provide additional diagnostic information. When compared with this level of ultrasound expertise, MRI gave additional information in 29% of cases, but only resulted in change in management in about 13%.

"Multicystic dysplastic kidney (Potter type II syndrome) and agenesis of corpus callosum (ACC) in two consecutive pregnancies: a possible teratogenic effect of electromagnetic exposure in utero"

Agenesis of the corpus callosum is found in about 5 per 1,000 births and it is due to maldevelopment or, secondary, to destructive lesions. Multicystic dysplastic kidneys is a consequence of either developmental failure of the mesonephric blastema to form nephrons or to early urinary obstruction due to urethral or ureteric atresia and can be found in about 1 per 1,000 live births. A case of fetal multicystic dysplastic kidney disease (Potter type II syndrome) and complete agenesis of the corpus callosum demonstrated by the presence of Probst bundles associated with colpocephaly occurring in the same mother in her two consecutive pregnancies is reported. Data regarding possible teratogenetic effect due to electromagnetic exposure in utero have also been investigated and raised suspicionus as a potential risk factor. In cases of suspected second trimester ultrasound diagnosis of agenesis of corpus callosum (ACC), the following clinical management should be recommended: fetal karyotype; a second level scan with differentiation between underlying conditions such as hydrocephalus and holoprosencephaly; antenatal MRI to enhance the diagnostic accuracy of possible associated neuronal migration (when possible); and direct demonstration of the presence of the Probst bundles to neurohistology.

Fetal ventriculomegaly: prognosis in cases in which prenatal neurosurgical consultation was sought

OBJECT

The prognosis of fetal ventriculomegaly (FVM) varies because of the disease's heterogeneity and the diversity of accompanying anomalies. Moreover, the cases that are referred to neurosurgeons may have different clinical features from those typically encountered by obstetricians. The object of this study was to delineate the prognosis of FVM in cases for which neurosurgical consultation was sought.

METHODS

Forty-four cases of FVM that were diagnosed before birth and referred to neurosurgeons for prenatal consultation were analyzed retrospectively. Twenty-five of the 44 patients had accompanying anomalies, but in only three (12%) of the cases were they detected prenatally. Postnatal imaging studies revealed that agenesis of the corpus callosum (nine cases) was the most common associated anomaly. Neuronal migration disorders, periventricular leukomalacia, and arachnoid cysts were present in four cases each, and aqueductal stenosis was present in three cases. Thirty-three patients were followed up longer than 11 months; in 15 (45%) delayed cognitive and/or motor development was documented, and all had accompanying anomalies. All 10 of the patients with isolated FVM exhibited normal development during the follow-up period. Eleven (25%) of the 44 patients underwent neurosurgical interventions for ventriculomegaly, which included ventriculoperitoneal shunt placement in seven cases. Four patients (9%) died.

CONCLUSIONS

The authors conclude that delayed development and disturbed functional status in patients in whom FVM was diagnosed prenatally are closely related to the presence of certain accompanying anomalies. On postnatal examination, more than half of the patients in whom the diagnosis of FVM was based on ultrasonography findings and whose parents were offered prenatal neurosurgical consultation were found to have additional anomalies that were not detected prenatally. Because of the possibility of additional undiagnosed anomalies, consulting neurosurgeons should be cautious in giving a prognosis in cases of FVM, even when prenatal ultrasonography reveals isolated ventriculomegaly and tests for intrauterine infection and chromosomal abnormality yield negative results.

Prenatal diagnosis of malformations of cortical development by dedicated neurosonography

OBJECTIVE

Malformations of cortical development (MCD) are rarely diagnosed in utero. We describe and compare the ultrasonographic and pathology findings in a cohort of fetuses with MCD.

METHODS

Fetuses with MCD were identified among all fetuses evaluated for suspected brain anomalies at the Fetal Neurology Clinic, and the ultrasonographic findings were compared with the results of the pathology examination.

RESULTS

We suspected the presence of MCD by ultrasonography in 23 fetuses. The mean gestational age at the time of ultrasound diagnosis was 26.2 (range, 18-40) weeks. The ultrasonographic findings leading to the diagnosis of MCD were abnormally overdeveloped gyri and sulci for gestational age (n = 7), delay in sulcation (n = 5), abnormally thin cortex (n = 5) abnormally wide and broad sulci (n = 3), bulging into the lateral ventricle (n = 1), cortical cleft (n = 1), and multiple intraparenchymal echogenic nodules (n = 1). All fetuses had associated central nervous system (CNS) and/or non-CNS anomalies. Pathology examination (performed in 17 fetuses) confirmed MCD in 16.

CONCLUSIONS

Cortical malformations can be diagnosed in utero by ultrasonography based on the presence of specific deviations from the normal pattern of development. The identified cases may represent the more severe forms in the MCD spectrum. The pathology findings do not always conform to the current classification systems of MCD but help in differentiating between possible genetic and acquired etiologies and in some cases provide a definitive syndromic diagnosis.

Outcome of prenatally diagnosed agenesis of the corpus callosum

OBJECTIVE

To investigate the natural history, associated abnormalities and outcome in fetuses diagnosed prenatally with agenesis of the corpus callosum (ACC).

METHODS

A retrospective study of all cases of prenatally detected ACC was performed in patients referred to two tertiary units between January 1993 and October 2003. Associated abnormalities, pregnancy outcome and infant follow-up were recorded.

RESULTS

ACC was diagnosed in 117 cases. In 82 (70%) cases this was associated with other fetal structural (n = 49) or chromosomal abnormalities (n = 33). ACC was classified as an isolated prenatal finding in 35 (30%) cases. Assuming normal development in all cases lost to follow-up, significant developmental delay was present in 36% (95% CI, 15-65%) of isolated ACC. Furthermore, developmental delay was present in all cases with ventriculomegaly of at least 15 mm and in one of four cases with ventricular measurements less than 15 mm.

CONCLUSIONS

The outcome of prenatally detected ACC is mainly dependent on the presence or absence of associated anomalies. The full assessment of fetal ACC mandates karyotyping, MRI and a search for more subtle ultrasound features of certain genetic syndromes. In this series, at least 36% (95% CI, 15-65%) of cases with isolated ACC exhibited significant developmental delay when assessed postnatally.

Prenatal diagnosis of agenesis of corpus callosum: what is the neurodevelopmental outcome?

BACKGROUND

Corpus callosum is the largest cerebral commissure that connects neocortical areas. Agenesis of corpus callosum (ACC) can be partial or complete, isolated or associated with other malformations. Its prenatal diagnosis creates problems within parental counselling due to its uncertain prognosis. The aim of this study was to correlate the neurodevelopmental outcome with both the clinical picture and the neuroradiological features, in order to improve prenatal parental counselling in a group of nine children with ACC, prenatally diagnosed by ultrasound and then confirmed by postnatal magnetic resonance imaging (MRI).

METHODS

In all patients, cerebral ultrasound scans, electroencephalogram (EEG) examinations, cerebral MRI, cytogenetic analysis, general physical evaluation, neurological examination and neuropsychological assessment (Griffiths Scale, Wechsler Primary and Preschool Scale of Intelligence, Wechsler Intelligence Scale for Children) were carried out.

RESULTS

In six patients the callosal agenesis was isolated, while in 3/9 it was associated with other cerebral malformations. Children with isolated callosal agenesis were asymptomatic or presented a mild hypotonia and the EEG was normal in five of them. All children with other associated brain malformations presented epilepsy, poor psychomotor development and cerebral palsy.

CONCLUSION

The prenatal suspicion of ACC needs an accurate diagnostic approach, in order to well determine its isolated or associated nature, linked to different neurodevelopmental outcome.

Fetal central nervous system MR imaging

MR imaging of the fetal brain is rapidly being embraced in clinical practice. Fetal MR imaging is proving to be a powerful modality with which to evaluate the fetal brain and is a valuable complement to prenatal ultrasound. Structural abnormalities, such as cerebral malformations and destructive lesions, can be sonographically occult on prenatal ultrasound yet detectable by fetal MR imaging. Moreover, fetal MR imaging offers the promise of contributing to our understanding of normal as well as abnormal brain development with continued advances in MR imaging techniques, such as diffusion-weighted and parallel imaging.

Characteristics, associations and outcome of partial agenesis of the corpus callosum in the fetus

OBJECTIVES

To report, in a population of fetuses diagnosed with partial agenesis of the corpus callosum (PACC), the sonographic characterization, incidence of cerebral, extracerebral and chromosomal anomalies, and outcome. In addition, in some of our cases a comparison was made between findings on ultrasound and fetal magnetic resonance imaging (MRI).

METHODS

This was a retrospective study of all cases of PACC seen at two referral centers for prenatal diagnosis of congenital anomalies over a 10-year period. The following variables were assessed: indication for referral, additional cerebral and extracerebral malformations, chromosomal abnormalities, and pregnancy and fetal/neonatal outcome.

RESULTS

Among 54 cases of fetal agenesis of the corpus callosum detected in the referral centers during the observation period, PACC was diagnosed at prenatal sonography in 20 cases and confirmed at pre/postnatal MRI and necropsy examinations in 19 cases (35%). These 19 constituted the study group. The diagnosis was made in the sagittal planes and in 12 cases it was made prior to 24 weeks. In most cases the indication for referral was the presence of indirect signs of callosal anomalies, such as colpocephaly. In 10 cases PACC occurred in association with other anomalies and in nine it was isolated. MRI was particularly useful for demonstrating some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. Regarding pregnancy outcome, of those diagnosed before 24 weeks which had associated anomalies, all except two were terminated. Of the nine cases with isolated PACC, all were liveborn. Follow-up was available in eight, and two of these (25%) showed evidence of significant developmental delay. In our series the outcome of isolated PACC was not better than that of complete agenesis of the corpus callosum reported in other series.

CONCLUSIONS

PACC can be diagnosed reliably and characterized in prenatal life. The sonographic sign present in most cases is colpocephaly. Prenatal MRI can be performed to confirm the diagnosis. It is particularly useful to demonstrate some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. The relatively poor survival rate is due to the high rate of terminations and associated major anomalies.

Fetal magnetic resonance imaging in the evaluation of fetuses referred for sonographically suspected abnormalities of the corpus callosum

OBJECTIVE

Fetal magnetic resonance imaging (MRI) has been shown to be useful in assessing the developing central nervous system. However, its utility in specific brain disorders has not been well investigated. We hypothesized that fetal MRI can better assess the integrity of the brain in cases with sonographically suspected callosal abnormalities.

METHODS

We retrospectively reviewed fetal MRI and prenatal sonographic studies of 10 fetuses referred for MRI for sonographically suspected callosal abnormalities.

RESULTS

An abnormal corpus callosum was identified on fetal MRI in 80% of cases. The type of callosal abnormality (complete or partial agenesis) was similar on both prenatal sonography and fetal MRI in all cases. All sonographically identified additional brain abnormalities were detected on fetal MRI, with the exception of choroid plexus cysts. Furthermore, in 63% (5 of 8) of cases with a callosal abnormality on both sonography and fetal MRI, additional brain abnormalities were detected on fetal MRI that were not apparent on sonography. These sonographically occult findings were confirmed on postnatal MRI or autopsy in 3 of 5 patients.

CONCLUSIONS

Fetal MRI is an important adjunct to sonography in assessing the corpus callosum and other aspects of brain development when agenesis of the corpus callosum is suspected. It can identify frequent additional findings that are not visible on sonography such as abnormal sulcation. In light of the association between additional brain abnormalities and worse neurodevelopmental outcome, the potential of fetal MRI as an important adjunctive prognostic imaging test in fetuses with callosal agenesis can now be tested.

Les agénésies isolées et familiales du corps calleux sont-elles de bon pronostic ?

Agenesia of corpus callosum belongs to a group of cerebral malformations whose prognosis is uncertain. In such cases, assessment of prognosis may benefit from eventual associated fetal, obstetrical or familial features. We report a patient with an isolated corpus callosum agenesia that led to the discovery of a similar malformation in her father. This observation demonstrates that some forms of isolated and familial corpus callosum agenesia could have a favorable outcome. However, the difficulty of the assessment of prognosis in isolated corpus callosum agenesia is emphasized and the question of parental RMI exploration in such a peculiar context is raised.

Magnetic resonance imaging and ultrasound in the assessment of the fetal central nervous system

Ultrasound is the screening modality of choice for evaluation of the fetal central nervous system (CNS). However, in cases of difficult diagnosis further fetal investigation is desirable. Due to ultrafast magnetic resonance imaging (MRI) techniques artifacts from fetal motions are minimized. MRI involves no exposure to radiation and hence appears to be safe. Due to the better soft tissue contrast, additional investigation by MRI may extend the sonographic diagnosis of fetal CNS-anomalies. Ultrasound and MRI are complementary imaging methods in the evaluation of the fetal CNS. The most important indications for ultrasound are screening for CNS anomalies and serial assessment of the dynamic of the disorder. The most important indications for fetal MRI are the "second opinion" and investigation by fetal MRI instead of postpartum MRI (especially in cases of planned postpartum intervention). In this article the indications and limitations of ultrasound and magnetic resonance imaging in the evaluation of the fetal CNS are discussed.

Sonography of fetal cerebrospinal anomalies

Congenital anomalies of the central nervous system (CNS) are among the most frequent malformations. Current ultrasound equipment can give a precise diagnosis of many of these lesions from early gestation. High-resolution transvaginal probes play a major role both in allowing an early diagnosis and for better defining subtle details of both normal and abnormal cerebral anatomy. The diagnostic accuracy of prenatal ultrasound is, however, heavily dependent upon the expertise of the sonologist, the type of equipment employed, and the time dedicated to the scan. Fetal sonography is effective in identifying neural tube defects, although alpha-fetoprotein screening seems to give a greater sensitivity. The accuracy of ultrasound in the identification of CNS malformations other than neural tube defects remains unclear because of the ascertainment biases of the few large prospective studies that have been conducted to date.

Central nervous system anomalies

Fetal central nervous system abnormalities encompass a variety of lesions. Most of the anomalies are seen in association with an increased incidence of fetal aneuploidy and an increase in other anomalies both within and outside of the central nervous system. These associated findings and the underlying lesion all have a role in the eventual prognosis for the ongoing pregnancy. The antenatal diagnosis of a central nervous system abnormality should prompt a careful search for other defects, and consideration should be given for genetic evaluation and testing.

Agenesis of corpus callosum: clinical description and etiology

In 135 children (aged 3 months to 15 years) with structural defects of the central nervous system found on magnetic resonance imaging, agenesis of the corpus callosum was evident in 7. The etiology of agenesis of the corpus callosum has been established in four children: partial trisomy of chromosome 13, partial duplication of the long arm of chromosome 10, Aicardi's syndrome, and intracranial bleeding during the fetal period as a result of injury. Agenesis of the corpus callosum coexisted with a Dandy-Walker malformation in one other patient, which suggests a genetic etiology. In spite of these variable etiologies, dysmorphic features were identified in all seven patients, as was psychomotor retardation. Epileptic seizures had occurred in six patients, and all manifested abnormalities on neurologic examination.

Genetic counselling in prenatally diagnosed non-chromosomal fetal abnormalities

Advances in technology and skills have resulted in the improved detection of fetal ultrasound abnormalities by ultrasound. In addition, the development of new diagnostic methods has resulted in major advances in our ability to detect microscopic and submicroscopic chromosome abnormalities as well as single gene disorders. This often enables us to provide the family with accurate information regarding the aetiology, prognosis, the risk of recurrence and the prenatal diagnosis options available in future pregnancies. Genetic counselling is important because this information should be communicated to the family in simple language, with care and sensitivity, so that the family can make decisions that are fully informed.

Ultrasound of the fetal central nervous system

Current ultrasound equipment allows the antenatal identification of many central nervous system anomalies from early gestation. In selected cases, special techniques (transvaginal sonography, three-dimensional ultrasound, colour Doppler) may enhance the diagnostic potential. Diagnostic accuracy, however, remains heavily dependent upon the expertise of the sonologist. Fetal ultrasound is effective in identifying neural tube defects, although alpha-fetoprotein screening seems to yield a greater sensitivity. The sensitivity in the diagnosis of central nervous system malformations other than neural tube defects remains unclear because of the ascertainment biases of the few large prospective studies that have been carried out so far. Magnetic resonance imaging may play a major role in the evaluation of cases with suboptimal ultrasound visualization, or when specific anomalies are suspected, such as intracranial haemorrhage or migrational disorders.

[Agenesis of the corpus callosum: etiological and clinical aspects, diagnostic methods and prognosis]

Agenesis of the corpus callosum is a frequent congenital malformation with many etiologies and clinical features. It can occur as an isolated defect which is usually sporadic, it is frequently associated with other malformations, genetic syndromes and metabolic disorders. Ante- or postnatal diagnosis must be followed by a careful search for etiology, and it raises uncertain and difficult question with regard to pregnancy continuation and infant development.

Clinical outcome of mild fetal ventriculomegaly

OBJECTIVE

Our purpose was to evaluate the outcome of fetuses with mild cerebral ventriculomegaly.

STUDY DESIGN

We prospectively collected all cases of mild cerebral ventriculomegaly (transverse diameter of the atrium of the cerebral lateral ventricles between 10 and 15 mm) diagnosed antenatally between January 1990 and December 1996. Associated ultrasonographic abnormalities including markers of aneuploidy, presence of chromosomal anomalies, structural malformations detected at birth, and neurologic outcome were recorded. Outcome information was available on all cases. In addition, published series of cases of fetal mild cerebral ventriculomegaly were reviewed to identify prognostic indicators.

RESULTS

Eighty-two cases fulfilled the inclusion criteria: 48 were isolated and 34 were associated with other ultrasonographic markers or anomalies. Among the 45 surviving euploid isolated cases, neurologic follow-up was normal at a mean age of 28 months (range 3 to 72 months). Male fetuses and those with a transverse atrial size <12 mm had a good prognosis. Ventricular atria > or =12 mm were more often associated with other anomalies (56% vs 6%) and, when isolated, with abnormal postnatal neurodevelopment (23% vs 3%). Aneuploidy was present in two cases of isolated mild cerebral ventriculomegaly, both of which were associated with advanced maternal age, and in seven cases associated with other anomalies.

CONCLUSIONS

Mild cerebral ventriculomegaly should prompt targeted ultrasonographic examination, inclusive of markers of aneuploidies, visualization of the corpus callosum, and echocardiogram as well as serologic evaluation for congenital infections. In isolated mild cerebral ventriculomegaly genetic counseling should take into account clinical, laboratory, and ultrasonographic findings. A review of the published series suggests that cognitive or motor delay is predominantly mild and that it occurs in about 9% of cases of isolated mild cerebral ventriculomegaly.

[Mental prognosis of Apert syndrome]

BACKGROUND

Mental retardation, considered as common in Apert syndrome could be in part due to associated brain abnormalities.

POPULATION AND METHODS

Sixty patients (32 males, 28 females) were included in the study. Patient age at the last examination was over 3 years (mean 10 years, range 3-28 years) in 38 patients. IQ was assessed from psychometric tests adapted for age. Brain anatomy was studied by MRI. Age at operation and quality of familial environment were also evaluated.

RESULTS

The IQ was over 70 in 12 patients (32%), over 90 in five (13%) and the mean IQ was 62 (10-114). Thirty percent of patients had abnormalities of the corpus callosum, 43% of the cerebral ventricles and 55% of the septum pellucidum. There was no anomaly in 28% of the patients. One or more operations were performed in 53 patients, before one year of age in 37. Ten children were institutionalized or in deleterious family situation. The main factor influencing the mental prognosis was the age at operation: the final IQ was over 70 in 50% of the children operated on before one year of age versus 8% in those operated on later (P = 0.01). Only the anomalies of the septum pellucidum seemed to play a role: 50% of the patients with normal septum had an IQ > 70 compared to 18% in those with septum anomalies (P < 0.04). The quality of the familial environment also influenced the mental development: 12.5% of the patients who were institutionalized or in difficult familial situation had an IQ > 70 compared to 39% of those who live in a normal family.

CONCLUSIONS

Careful investigation including MRI is necessary for detecting associated brain abnormalities. The patients must be operated on early, if possible before the age of nine months. Attention has also to be paid to quality of the sociofamilial environment.

Prognosis for mental function in Apert's syndrome

The factors involved in the mental development of patients with Apert's syndrome were studied by the authors, focusing on the age of the patient at operation, associated brain malformations, and the quality of the family environment. Overall, 32% of patients with significant follow-up review had an intelligence quotient (IQ) greater than 70. Age at operation appeared to be the main factor associated with changes in mental development: final IQ was greater than 70 in 50% of patients operated on before 1 year of age versus only 7.1% in patients operated on later in life (p = 0.01). Malformations of the corpus callosum and size of the ventricles played no role in the final IQ, whereas anomalies of the septum pellucidum had a significant effect, with the proportion of patients with an IQ over 70 increasing more than twofold in patients with a normal septum compared with patients with septal anomalies (p < 0.04). Quality of the family environment was the third factor involved in intellectual achievement: only 12.5% of institutionalized children reached a normal IQ level compared to 39.3% of children from a normal family background.