Loss-of-function variants in ZEB1 cause dominant anomalies of the corpus callosum with favourable cognitive prognosis

BACKGROUND

The neurodevelopmental prognosis of anomalies of the corpus callosum (ACC), one of the most frequent brain malformations, varies extremely, ranging from normal development to profound intellectual disability (ID). Numerous genes are known to cause syndromic ACC with ID, whereas the genetics of ACC without ID remains poorly deciphered.

METHODS

Through a collaborative work, we describe here ZEB1, a gene previously involved in an ophthalmological condition called type 3 posterior polymorphous corneal dystrophy, as a new dominant gene of ACC. We report a series of nine individuals with ACC (including three fetuses terminated due to ACC) carrying a ZEB1 heterozygous loss-of-function (LoF) variant, identified by exome sequencing.

RESULTS

In five cases, the variant was inherited from a parent with a normal corpus callosum, which illustrates the incomplete penetrance of ACC in individuals with an LoF in ZEB1. All patients reported normal schooling and none of them had ID. Neuropsychological assessment in six patients showed either normal functioning or heterogeneous cognition. Moreover, two patients had a bicornuate uterus, three had a cardiovascular anomaly and four had macrocephaly at birth, which suggests a larger spectrum of malformations related to ZEB1.

CONCLUSION

This study shows ZEB1 LoF variants cause dominantly inherited ACC without ID and extends the extraocular phenotype related to this gene.

The neuropsychology and neuroanatomy of reduplicative paramnesia

Reduplicative paramnesia refers to the delusional belief that there are identical places in different locations. In this case-control study we investigated the clinical, phenomenological, neuropsychological and neuroanatomical data of eleven patients with reduplicative paramnesia and compared them against a control group of eleven patients with severe spatial disorientation without signs of reduplicative paramnesia. We show that most patients with reduplicative paramnesia report that a current place is reduplicated and/or relocated to an other familiar place. Patients with reduplicative paramnesia show a higher prevalence of deficits in the executive functions compared to the control patients, while mnestic and visuo-spatial deficits were both frequent in patients with reduplicative paramnesia and the control group. Patients with reduplicative paramnesia mostly suffer from right hemispheric lesions with a maximal overlap in the dorsolateral prefrontal cortex. Using lesion network mapping we show that lesions causing reduplicative paramnesia are connected to bilateral anterior insula and the right cingulate cortex. We argue that patients with reduplicative paramnesia fail to integrate the actual context with visuo-spatial memories and personal relevant emotional information due to a disruption of the neural network within the anterior temporal lobe, the cingulate cortex and the anterior insula. Also patients with reduplicative paramnesia are not able to resolve this conflict due to the lesion of the dorsolateral prefrontal cortex and executive dysfunction.

Prognostic value of diffusion-weighted magnetic resonance imaging of brain in fetal growth restriction: results of prospective multicenter study

OBJECTIVE

To measure prospectively apparent diffusion coefficient (ADC) values between 28 and 32 weeks of gestation in different cerebral territories of fetuses with estimated fetal weight (EFW) ≤ 5^th centile, and analyze their association with adverse perinatal outcome.

METHODS

This was a prospective study involving six tertiary-level perinatal centers. In the period 22 November 2016 to 11 September 2017, we included singleton, small-for-gestational-age (SGA) fetuses with EFW ≤ 5^th percentile, between 28 and 32 weeks of gestation, regardless of the umbilical artery Doppler and maternal uterine artery Doppler findings. A fetal magnetic resonance imaging (MRI) examination with diffusion-weighted sequences (DWI) was performed within 14 days following inclusion and before 32 weeks. ADC values were calculated in the frontal and occipital white matter, basal ganglia and cerebellar hemispheres. An ultrasound examination was performed within 1 week prior to the MRI examination. The primary outcome was a composite measure of adverse perinatal outcome, defined as any of the following: perinatal death; admission to neonatal intensive care unit with mechanical ventilation > 48 h; necrotizing enterocolitis; Grade III-IV intraventricular hemorrhage; periventricular leukomalacia. A univariate comparison of median ADC values in all cerebral territories between fetuses with and those without adverse perinatal outcome was performed. The association between ADC values and adverse perinatal outcome was then analyzed using multilevel logistic regression models to adjust for other common prognostic factors for growth-restricted fetuses.

RESULTS

MRI was performed in 64 patients, of whom five were excluded owing to fetal movement artifacts on DWI and two were excluded for termination of pregnancy with no link to fetal growth restriction (FGR). One intrauterine death occurred secondary to severe FGR. Among the 56 liveborn neonates, delivered at a mean ± SD gestational age of 33.6 ± 3.0 weeks, with a mean birth weight of 1441 ± 566 g, four neonatal deaths occurred. In addition, two neonates required prolonged mechanical ventilation, one of whom also developed necrotizing enterocolitis. Overall, therefore, seven out of 57 (12.3%) cases had an adverse perinatal outcome (95% CI, 3.8-20.8%). The ADC values in the frontal region were significantly lower in the group with adverse perinatal outcome vs those in the group with favorable outcome (mean values of both hemispheres, 1.68 vs 1.78 × 10^-3  mm² /s; P = 0.04). No significant difference in ADC values was observed between the two groups in any other cerebral territory. A cut-off value of 1.70 × 10^-3  mm² /s was associated with a sensitivity of 57% (95% CI, 18-90%), a specificity of 78% (95% CI, 63-88%), a positive predictive value of 27% (95% CI, 8-55%) and a negative predictive value of 93% (95% CI, 80-98%) for the prediction of adverse perinatal outcome. A mean frontal ADC value < 1.70 × 10^-3  mm² /s was not associated significantly with an increased risk of adverse perinatal outcome, either in the univariate analysis (P = 0.07), or when adjusting for gestational age at MRI and fetal sex (odds ratio (OR), 6.06 (95% CI, 0.9-37.1), P = 0.051) or for umbilical artery Doppler (OR, 6.08 (95% CI, 0.89-41.44)).

CONCLUSION

This first prospective, multicenter, cohort study using DWI in the setting of SGA found lower ADC values in the frontal white-matter territory in fetuses with, compared with those without, adverse perinatal outcome. To determine the prognostic value of these changes, further standardized evaluation of the neurodevelopment of children born with growth restriction is required. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal exome sequencing in 65 fetuses with abnormality of the corpus callosum: contribution to further diagnostic delineation

PURPOSE

Abnormality of the corpus callosum (AbnCC) is etiologically a heterogeneous condition and the prognosis in prenatally diagnosed cases is difficult to predict. The purpose of our research was to establish the diagnostic yield using chromosomal microarray (CMA) and exome sequencing (ES) in cases with prenatally diagnosed isolated (iAbnCC) and nonisolated AbnCC (niAbnCC).

METHODS

CMA and prenatal trio ES (pES) were done on 65 fetuses with iAbnCC and niAbnCC. Only pathogenic gene variants known to be associated with AbnCC and/or intellectual disability were considered.

RESULTS

pES results were available within a median of 21.5 days (9-53 days). A pathogenic single-nucleotide variant (SNV) was identified in 12 cases (18%) and a pathogenic CNV was identified in 3 cases (4.5%). Thus, the genetic etiology was determined in 23% of cases. In all diagnosed cases, the results provided sufficient information regarding the neurodevelopmental prognosis and helped the parents to make an informed decision regarding the outcome of the pregnancy.

CONCLUSION

Our results show the significant diagnostic and prognostic contribution of CMA and pES in cases with prenatally diagnosed AbnCC. Further prospective cohort studies with long-term follow-up of the born children will be needed to provide accurate prenatal counseling after a negative pES result.

Callosal agenesis and congenital mirror movements: outcomes associated with DCC mutations

Pathogenic variants in the gene encoding deleted in colorectal cancer (DCC) are the first genetic cause of isolated agenesis of the corpus callosum (ACC). Here we present the detailed neurological, brain magnetic resonance imaging (MRI), and neuropsychological characteristics of 12 individuals from three families with pathogenic variants in DCC (aged 8-50y), who showed ACC and mirror movements (n=5), mirror movements only (n=2), ACC only (n=3), or neither ACC nor mirror movements (n=2). There was heterogeneity in the neurological and neuroimaging features on brain MRI, and performance across neuropsychological domains ranged from extremely low (impaired) to within normal limits (average). Our findings show that ACC and/or mirror movements are associated with low functioning in select neuropsychological domains and a DCC pathogenic variant alone is not sufficient to explain the disability. WHAT THIS PAPER ADDS: Neuropsychological impairment severity is related to presence of mirror movements and/or agenesis of the corpus callosum. A DCC pathogenic variant in isolation is associated with the best prognosis.

Added value of MRI for the diagnosis of adnexal torsion in children and adolescents after inconclusive ultrasound examination

PURPOSE

The purpose of this study was to assess the performance of magnetic resonance imaging (MRI) in children and adolescents with suspected adnexal torsion (AT) after inconclusive initial ultrasound examination.

MATERIALS AND METHODS

Twenty-eight girls with a mean age of 12±4 (SD) years (range: 1 month to 18years) were included. All had clinically suspected AT and inconclusive initial ultrasound findings followed by pelvic MRI as a second-line imaging modality. The final diagnosis was obtained by surgery or follow-up. Two radiologists blinded to the clinical, ultrasound and surgical data, retrospectively and independently reviewed MRI examinations. Clinical and MRI features associated with AT were searched for using univariate analyses.

RESULT

Among the 28 patients, 10/28 patients (36%) had AT and 22/28 (79%) had an ovarian or tubal mass. AT was associated with an age<13years (OR: 10.7; 95% CI: 1.3-148.2) (P=0.022) and a whirlpool sign at MRI (OR: 61.0; median unbiased estimate, 7.2) (P<0.0001). When a mass was present, the best quantitative MRI criteria for AT were mass volume and ovary-corrected volume≥30cm³ (κ=0.72 and 0.61, respectively), mass axis length≥5cm (κ=0.90), and mass surface area≥14 cm² (κ=0.58), with moderate to almost perfect interobserver agreement. The overall sensitivity, specificity and accuracy of MRI for the diagnosis of AT were 100% (10/10; 95% CI: 69-100), 94% (17/18; 95% CI: 73-100) and 96% (27/28; 95% CI: 82-100) respectively, with perfect interobserver agreement (κ=1).

CONCLUSION

In pediatric patients with suspected AT and inconclusive initial ultrasound examination, a strategy including MRI as a second-line imaging modality should be considered if MRI does not delay a potential surgery.

New insights in cerebral findings associated with fetal myelomeningocele: a retrospective cohort study in a single tertiary centre

OBJECTIVE

To investigate cerebral anomalies other than Chiari type 2 malformation in fetuses with myelomeningocele (MMC).

DESIGN

A retrospective cohort study in a single tertiary centre.

SETTING

A review of associated cerebral anomalies in cases with prenatal diagnosis of myelomeningocele.

POPULATION

Seventy cases of fetal myelomeningocele.

METHODS

Ultrasound and MRI images were blindly reviewed. Postnatal imaging and results of the postmortem results were also reviewed. The association between cerebral anomalies and the following ultrasound findings was measured: level of the defect, ventriculomegaly, microcephaly and fetal talipes.

MAIN OUTCOME MEASURES

A microcephaly was observed in 32/70 cases (46%) and a ventriculomegaly was observed in 39/70 cases (56%). Other cerebral anomalies were diagnosed in 47/70 (67%).

RESULTS

Other cerebral anomalies were represented by 42/70 cases with abnormal CC (60%), 8/70 cases with perinodular heterotopia (PNH; 11%), 2/70 cases with abnormal gyration (3%). MRI performed only in fetal surgery cases confirmed the ulltrasound findings in all cases and provided additional findings in two cases (PNH). Risk ratios of fetal cerebral anomalies associated with MMC did not reach significance for microcephaly, ventriculomegaly, talipes or the level of the defect There was an overall good correlation between pre- and postnatal findings with a Kappa value of 0.79 [95% CI 0.57-1] and 82% agreement.

CONCLUSION

Fetal brain anomalies other than Chiari type 2 malformation are frequently observed in fetuses with myelomeningocele, predominantly represented by CC anomalies. Whether these associated cerebral anomalies have an impact on selecting cases eligible for fetal surgery needs further evaluation.

TWEETABLE ABSTRACT

Fetal cerebral anomalies other than Chiari type 2 malformation, microcephaly, and ventriculomegaly may be associated with MMC in up to 67% of the cases.

Evaluation of septal insertion of atrioventricular valves in fetuses by postmortem 4.7 Tesla cardiac MRI: A feasibility study

PURPOSE

The purpose of this study was to compare non-invasive high-spatial-resolution postmortem cardiac magnetic resonance imaging (MRI) and autopsy findings for evaluating the septal insertion of atrioventricular valves in fetuses.

MATERIALS AND METHODS

Five fetal heart specimens including two normal hearts, one heart with complete atrioventricular septal defect (AVSD) and two hearts with linear insertion of atrioventricular valves (LIAVV; gestational age 17 to 34 weeks) were studied with cardiac MRI using a 4.7 T MRI scanner without sample preparation. Three (3D) and two-dimensional (2D) turbo-RARE (rapid imaging with refocused echoes) sequences in four-chamber and left-ventricular long-axis planes were obtained with a minimal isotropic/in-plane resolution of 156μm. Nonparametric tests were performed to compare the distance between insertions of medial leaflets of the atrioventricular valves and the inlet/outlet distance ratio between MRI and autopsy findings in normal, complete AVSD and with linear insertion of atrioventricular valves (LIAVV) fetal hearts.

RESULTS

Despite apparent differences between LIAVV/normal hearts, no significant differences were found between differential insertion of medial leaflets and inlet/outlet distance ratios with both techniques. Very good to excellent reliability between both techniques was found for differential insertion (ICC: 87.2%; 95% CI: -21.7%, 99.1%) (P=0.963) and inlet/outlet distance ratio (ICC 98.3%; 95%CI: 85.2%, 99.8%) (P=0.537) measurements.

CONCLUSION

Postmortem cardiac MRI could replace autopsy for assessing normal or abnormal septal insertion of atrioventricular valves in fetuses without requiring specific preparation of the heart.

Towards ontology-based decision support systems for complex ultrasound diagnosis in obstetrics and gynecology

INTRODUCTION

We have developed a new knowledge base intelligent system for obstetrics and gynecology ultrasound imaging, based on an ontology and a reference image collection. This study evaluates the new system to support accurate annotations of ultrasound images. We have used the early ultrasound diagnosis of ectopic pregnancies as a model clinical issue.

MATERIAL AND METHODS

The ectopic pregnancy ontology was derived from medical texts (4260 ultrasound reports of ectopic pregnancy from a specialist center in the UK and 2795 Pubmed abstracts indexed with the MeSH term "Pregnancy, Ectopic") and the reference image collection was built on a selection from 106 publications. We conducted a retrospective analysis of the signs in 35 scans of ectopic pregnancy by six observers using the new system.

RESULTS

The resulting ectopic pregnancy ontology consisted of 1395 terms, and 80 images were collected for the reference collection. The observers used the knowledge base intelligent system to provide a total of 1486 sign annotations. The precision, recall and F-measure for the annotations were 0.83, 0.62 and 0.71, respectively. The global proportion of agreement was 40.35% 95% CI [38.64-42.05].

DISCUSSION

The ontology-based intelligent system provides accurate annotations of ultrasound images and suggests that it may benefit non-expert operators. The precision rate is appropriate for accurate input of a computer-based clinical decision support and could be used to support medical imaging diagnosis of complex conditions in obstetrics and gynecology.

Optimization of the pediatric head computed tomography scan image quality: Reducing dose with an automatic tube potential selection in infants

PURPOSE

The objective of our study was to evaluate the impact of an automatic tube potential selection (ATPS) on the delivered dose and image quality in unenhanced head computed tomography (CT) scans of infants.

MATERIALS AND METHODS

Unenhanced head CT scans were acquired before and after the introduction of an ATPS in full automatic mode in two groups of 20 patients under one year of age. The delivered dose (CDTIvol) as the quantitative (contrast-to-noise ratio) and qualitative (based on the European CT criteria) image quality were compared on the supra- and infratentorial regions by three senior pediatric radiologists. Mann-Whitney and Fisher exact tests were performed. An interobserver Fleiss's kappa agreement was calculated for each criterion.

RESULTS

The use of an ATPS allowed a significant reduction in the delivered dose (-21%, p=0.0005) with no significant difference of the contrast-to-noise ratio in supra- (-5%, p=0.21) and infratentorial regions (+16%, p=0.96). In all cases, dose reduction was obtained with the same value of 100kV. It maintained a good qualitative image quality (e.g., differentiation between gray and white matter in supra-tentorial region: p=0.470). The interobserver Fleiss's kappa agreements were good to excellent.

CONCLUSION

ATPS is a tool that can significantly reduce the delivered dose by choosing the most appropriate tube voltage while maintaining image quality in unenhanced head CT scans of infants.

Prenatal features of isolated subependymal pseudocysts associated with adverse pregnancy outcome

OBJECTIVES

To identify at prenatal ultrasound (US) the features of apparently isolated subependymal pseudocysts (SEPC) that may indicate underlying pathology and should lead to further investigations.

METHODS

This was a retrospective study of cases with SEPC detected on prenatal US and/or magnetic resonance imaging (MRI). Those with apparently isolated SEPC at US were classified into two groups as follows: Group 1 (n = 29): normal prenatal US and MRI (except for SEPC) and normal outcome; Group 2 (n = 12): normal prenatal cerebral US (except for SEPC) and abnormal prenatal cerebral MRI with or without abnormal outcome. A third group (n = 9) included cases with abnormal prenatal US and MRI. The latter cases with obvious cerebral abnormalities at US were excluded from the statistical analysis as they do not represent a diagnostic dilemma for clinicians. Groups 1 and 2 were analyzed, comparing them with respect to their SEPC characteristics (size, number, location in relation to the caudothalamic notch and the ventricular horns and morphology) and extracerebral abnormalities.

RESULTS

The mean ± SD SEPC great axis was longer in Group 2 (11.67 ± 5.82 mm) than it was in Group 1 (8.00 ± 5.64 mm) (P = 0.021), suggesting an optimal cut-off for size of SEPC of ≥ 9 mm (sensitivity = 75%, specificity = 62%) to maximize sensitivity for predicting pathological outcome. SEPC adjacent to the temporal horns and SEPC located posterior to the caudothalamic notch were observed more frequently in Group 2, indicating their association with poor outcome (P = 0.003 and P = 0.003, respectively). Atypical morphology and extracerebral abnormalities were observed more frequently in Group 2 (P = 0.013 and P = 0.044, respectively). There was no statistically significant difference between groups for either number or location of cysts along the inferior wall or adjacent to the lateral wall of the frontal horns (P = 0.591 and P = 0.156, respectively).

CONCLUSION

When apparently isolated SEPC are observed at prenatal US, further investigations should be performed under the following circumstances: (1) SEPC great axis ≥ 9 mm; (2) SEPC adjacent to the occipital and temporal horns; (3) SEPC located posterior to the caudothalamic notch; (4) SEPC with atypical morphology.

Periventricular nodular heterotopia on prenatal ultrasound and magnetic resonance imaging

OBJECTIVES

To describe the prenatal ultrasound and magnetic resonance imaging (MRI) findings suggestive of periventricular nodular heterotopia (PNH).

METHODS

This retrospective case series included fetuses referred to our institution for brain MRI between 2007 and 2012, which were diagnosed with PNH and confirmed by postnatal MRI or autopsy. The type of PNH, associated ventriculomegaly and associated malformations are reported.

RESULTS

We included 11 fetuses (nine female, two male) with a mean gestational age at diagnosis of 31 (range, 23-34) weeks. PNH lesions were small and diffuse (n = 7), large and multiple (n = 1) or single (n = 3). A targeted ultrasound examination performed before fetal MRI missed the diagnosis in four cases (one diffuse and three single); a further ultrasound examination performed after MRI diagnosed PNH in two of these four cases. Ventriculomegaly was present in six cases (four unilateral and two bilateral). PNH appeared in all cases as nodules of intermediate echogenicity protruding into the ventricular lumen. In all cases of diffuse PNH, the frontal horns and bodies of the lateral ventricles appeared square in shape on coronal view, with irregular borders on axial view. Associated cerebral malformations were observed in seven cases and included corpus callosal agenesis (n = 4, with additional malformations in two) and retrocerebellar cyst (n = 3). Extracerebral malformations were also present in two cases. Maternal MRI was performed in five of the six cases of isolated small and diffuse PNH in female fetuses, and demonstrated PNH in two of these.

CONCLUSION

PNH is underdiagnosed at prenatal ultrasound, even on targeted scans. Irregular ventricular borders on axial view and irregular square-shaped lateral ventricles on coronal view are suggestive of PNH at prenatal ultrasound.

Correlation between pre- and postnatal cerebral magnetic resonance imaging

OBJECTIVES

To evaluate the diagnostic accuracy of fetal cerebral magnetic resonance imaging (MRI) on a large cohort and to compare pre- and postnatal MRI data.

METHODS

This prospective study included all cases referred to our unit for fetal cerebral MRI examination between June 2006 and December 2009 and which underwent at least one postnatal MRI examination. Cases in which there was termination of pregnancy, fetal death or stillbirth were excluded. The pre- and postnatal diagnoses established by MRI were compared and divided into five subgroups: same diagnosis on pre- and postnatal MRI (Group 1); same diagnosis but different appearance related to the natural course of the disease (Group 2); different diagnosis (related to limitations of fetal MRI) (Group 3); same diagnosis but with additional findings discovered on postnatal MRI examination (Group 4); or same diagnosis but different appearance related to the natural course of the disease (as in Group 2) and associated with additional findings discovered on postnatal MRI examination (Group 5). The prognostic impact of a possible disagreement between pre- and postnatal findings was evaluated.

RESULTS

One hundred fetuses were included. Fetal MRI was performed at a mean gestational age of 33 (range, 24-39) weeks and postnatal MRI at a mean age of 3.5 months. There were 53 cases classified as Group 1, 32 in Group 2, four in Group 3, 10 in Group 4 and one in Group 5. Thus, in 15 cases (Groups 3-5), there were discrepancies between pre- and postnatal findings (mostly related to corpus callosum anatomy, cortical and migration disorders). The discrepancy was judged to have a prognostic impact in 9/15 cases. Two postnatal MRI examinations were performed in eight cases, in one of which the second examination showed subependymal heterotopia which were not detectable on the first examination.

CONCLUSION

Pre- and postnatal MRI data showed good agreement in 85% of cases. There was disagreement with a prognostic impact in 9% of cases.

Abdominal imaging in child abuse

INTRODUCTION

Abdominal injuries in abused children are less common than musculoskeletal and craniocerebral injuries; however they carry high mortality and morbidity rates. In every case of trauma, regardless of aetiology, radiologists are responsible for the documentation and evaluation of injuries.

INJURIES

Any abdominal injury pattern maybe observed following physical abuse and none is specific for abuse. However, a high index of suspicion should be maintained for every case of pancreatic, hollow viscous and other solid organ injuries, especially when there is delay in seeking help, a history of trauma to the child or siblings, young age, undernourishment, ecchymosis in non-ambulatory children or a non-plausible explanation for the injuries based on the provided history and the psychomotor condition of the child.

IMAGING MODALITIES

CT with intravenous contrast material is the imaging modality of choice in every suspected inflicted abdominal injury. US could be the first imaging test for abused children with a low probability of abdominal injury and for follow-up. Upper gastrointestinal series could reveal acute or resolving mural haematomas in children with equivocal CT or US findings.

CONCLUSION

Child abuse should be considered in the differential diagnosis of acute abdominal symptoms in young children.

[Functional MR urography in children]

MR Urography (MRU) provides both morphologic and functional information without radiation exposure. It enables the assessment of split renal function, excretion, and quantification of obstruction. MRU is thus complementary to ultrasonography in the assessment of pre- and post-natal obstructive uropathies in children. If available, MRU should be definitely preferred to intravenous urography.

Catastrophic antiphospholipid syndrome and pulmonary embolism in a 3-year-old child

We report a rare example of catastrophic antiphospholipid syndrome (CAPS) in a young child. A 3-year-old girl with no previous medical history presented with extensive and recurrent thromboses. The diagnosis of CAPS was based on the occurrence of cardiopulmonary embolism in the child with a high titre of autoantibodies directed against phospholipids and beta-2-glycoprotein 1. In spite of a relatively rapid diagnosis and multiple treatments, the outcome was unfavourable. Multimodality imaging, including both ultrasonography and spiral CT, allowed close follow-up of the thromboses.