Agenesis of corpus callosum: clinical description and etiology

Reported congenital malformations after exposure to non-tumour necrosis factor inhibitor biologics: A retrospective comparative study in EudraVigilance

AIMS

To evaluate the number and nature of reported congenital malformations (CMs) after intrauterine exposure to non-tumour necrosis factor inhibitor biologics (non-TNFi biologics) compared to certolizumab pegol (CZP).

METHODS

A retrospective comparative study was conducted in the EudraVigilance (EV) database. A safe biologic (CZP) was considered as the reference group. Odds ratios (ORs) for CMs were calculated for each non-TNFi biologic (including abatacept, anakinra, belimumab, ixekizumab, rituximab, secukinumab, tocilizumab, ustekinumab and vedolizumab), versus CZP (quantitative assessment). Then, CM patterns were reviewed in consultation with a clinical geneticist (qualitative assessment).

RESULTS

ORs were not statistically significant except for belimumab and vedolizumab (similar in magnitude). Except for vedolizumab, no specific CM patterns were observed for the included non-TNFi biologics. Three cases of corpus callosum agenesis (CCA) were identified for vedolizumab (versus none in CZP and other investigated non-TNFi biologics). Two of the CCA cases were associated with other neurological CMs (one cerebral ventriculomegaly with microcephaly and one polymicrogyria). This may indicate that these CCAs are related to undiagnosed genetic alterations or are associated with the underlying maternal disease, although a definite relationship with vedolizumab exposure cannot be ruled out.

CONCLUSION

No special safety signal was identified regarding the occurrence of CMs after exposure to abatacept (n = 64), anakinra (n = 20), belimumab (n = 93), ixekizumab (n = 29), rituximab (n = 57), secukinumab (n = 128), tocilizumab (n = 124) and ustekinumab (n = 215). Regarding observed CCAs in the vedolizumab group (n = 113), no firm conclusions can be made based on available information.

CAMT-MPL: congenital amegakaryocytic thrombocytopenia caused by MPL mutations - heterogeneity of a monogenic disorder - a comprehensive analysis of 56 patients

Congenital amegakaryocytic thrombocytopenia caused by deleterious homozygous or compound heterozygous mutations in MPL (CAMT-MPL) is a rare inherited bone marrow failure syndrome presenting as an isolated thrombocytopenia at birth progressing to pancytopenia due to exhaustion of hematopoietic progenitors. The analysis of samples and clinical data from a large cohort of 56 patients with CAMT-MPL resulted in a detailed description of the clinical picture and reliable genotype-phenotype correlations for this rare disease. We extended the spectrum of CAMT causing MPL mutations regarding number (17 novel mutations) and impact. Clinical courses showed great variability with respect to the severity of thrombocytopenia, the development of pancytopenia and the consequences from bleedings. The most severe clinical problems were (i) intracranial bleedings pre- and perinatally and the resulting long-term consequences, and (ii) the development of aplastic anemia in the later course of the disease. An important and new finding was that thrombocytopenia was not detected at birth in a quarter of the patients. The rate of non-hematological abnormalities in CAMT-MPL was higher than described so far. Most of the anomalies were related to the head region (brain anomalies, ocular and orbital anomalies) and consequences of intracranial bleedings. The present study demonstrates a higher variability of clinical courses than described so far and has important implications on diagnosis and therapy. The diagnosis CAMT-MPL has to be considered even for those patients who are inconspicuous in the first months of life or show somatic anomalies typical for other inherited bone marrow failure syndromes.

Congenital amegakaryocytic thrombocytopenia - Not a single disease

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited bone marrow failure syndrome (IBMFS) that is characterized by severe thrombocytopenia at birth due to ineffective megakaryopoiesis and development towards aplastic anemia during the first years of life. CAMT is not a single monogenetic disorder; rather, many descriptions of CAMT include different entities with different etiologies. CAMT in a narrow sense, which is primarily restricted to the hematopoietic system, is caused mainly by mutations in the gene for the thrombopoietin receptor (MPL), sometimes in the gene for its ligand (THPO). CAMT in association with radio-ulnar synostosis, which is not always clinically apparent, is mostly caused by mutations in MECOM, rarely in HOXA11. Patients affected by other IBMFS - especially Fanconi anemia or dyskeratosis congenita - may be misdiagnosed as having CAMT when they lack typical disease features of these syndromes or have only mild symptoms. This article reviews scientific and clinical aspects of the various disorders associated with the term "CAMT" with a main focus on the disease caused by mutations in the MPL gene.

Agenesis of the Corpus Callosum in a Patient With Schizophrenia

The aim of this study is to report the case of a 25-year-old male with a history of schizophrenia who presented involuntarily to the psychiatric emergency department (ED) due to worsening agitation, paranoia, and disorganized behavior concerning a psychotic episode. During medical clearance to rule out acute organic causes of altered mental status prior to admission, the patient was found to have agenesis of the corpus callosum (ACC) on CT of the brain. ACC is a rare congenital disorder characterized by the partial or complete absence of the commissural pathway that connects the two cerebral hemispheres. This case presents a thought-provoking incidental anatomical finding in a patient with an acute exacerbation of chronic schizophrenia and allows for further discussion about the prevalence of undiagnosed malformations and possible underlying genetic contributions in patients with chronic mental illness.

Agenesis of the Corpus Callosum and Aicardi Syndrome: A Neuroimaging and Clinical Comparison

BACKGROUND

Agenesis of the corpus callosum can occur in individuals with epilepsy, either in isolation or as part of various neurological conditions, such as Aicardi syndrome. In this study, we evaluated the clinical and neuroradiological differences between children with nonsyndromic agenesis of the corpus callosum and those with Aicardi syndrome.

METHODS

We evaluated 31 children with epilepsy and agenesis of the corpus callosum (11 males, 20 females), 14 of whom had Aicardi syndrome (all females). We compared their clinical evaluations, radiological and electrophysiological findings, treatments, and their outcome.

RESULTS

Median age at seizure onset was lower in the Aicardi syndrome group compared with nonsyndromic agenesis of the corpus callosum (two versus five months, P = 0.006). The developmental impairment in terms of verbalization and ambulation was significantly worse in patients with Aicardi syndrome. The severity of magnetic resonance imaging (MRI) and glucose metabolism positron emission tomography (PET) involvement was more extensive in children with Aicardi syndrome than in nonsyndromic agenesis of the corpus callosum. In both groups, the PET scan showed a much more extensive area of involvement than suggested by the MRI scan. Four children underwent epilepsy surgery with significant improvement, but were not seizure free. Outcome was worse in those with PET showing abnormalities in the nonsurgical hemisphere despite normal appearance on MRI. All children who did not undergo surgery also continued to have seizures at last follow-up.

CONCLUSIONS

Children with Aicardi syndrome have earlier seizure onset, worse developmental outcome, and larger areas of brain abnormalities on neuroimaging compared with nonsyndromic agenesis of the corpus callosum patients. PET reveals larger area of abnormalities, compared with MRI. Although epilepsy surgery in agenesis of the corpus callosum may offer some palliative benefit in seizure frequency, none of our patients became seizure free.

Absent circle of Willis with vascular pollarding in an adult with colpocephaly: A developmental perspective

Absent circle of Willis (COW) has been described in cases of severe forms of cerebral developmental anomalies such as alobar prosencephaly. However, there are no reports of absent COW in patients with a milder form of cerebral abnormality such as colpocephaly. We report a unique case of an adult with colpocephaly and absent COW and discuss their association from a developmental perspective.

Clinical features and associated abnormalities in children and adolescents with corpus callosal anomalies

Callosal anomalies are frequently associated with other central nervous system (CNS) and/or somatic anomalies. We retrospectively analyzed the clinical features of corpus callosal agenesis/hypoplasia accompanying other CNS and/or somatic anomalies. We reviewed the imaging and clinical information of patients who underwent brain magnetic resonance imaging in our hospital, between 2005 and 2012. Callosal anomalies were isolated in 13 patients, accompanied by other CNS anomalies in 10 patients, associated with only non-CNS somatic anomalies in four patients, and with both CNS and non-CNS abnormalities in four patients. Out of 31 patients, four developed normally, without impairments in motor or cognitive functions. Five of nine patients with cerebral palsy were accompanied by other CNS and/or somatic anomalies, and showed worse Gross Motor Function Classification System scores, compared with the other four patients with isolated callosal anomaly. In addition, patients with other CNS anomalies also had a higher seizure risk.

Diffusion tensor imaging and fiber tractography in brain malformations

Diffusion tensor imaging (DTI) is an advanced MR technique that provides qualitative and quantitative information about the micro-architecture of white matter. DTI and its post-processing tool fiber tractography (FT) have been increasingly used in the last decade to investigate the microstructural neuroarchitecture of brain malformations. This article aims to review the use of DTI and FT in the evaluation of a variety of common, well-described brain malformations, in particular by pointing out the additional information that DTI and FT renders compared with conventional MR sequences. In addition, the relevant existing literature is summarized.

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.

Medial-based deformable models in nonconvex shape-spaces for medical image segmentation

We explore the application of genetic algorithms (GA) to deformable models through the proposition of a novel method for medical image segmentation that combines GA with nonconvex, localized, medial-based shape statistics. We replace the more typical gradient descent optimizer used in deformable models with GA, and the convex, implicit, global shape statistics with nonconvex, explicit, localized ones. Specifically, we propose GA to reduce typical deformable model weaknesses pertaining to model initialization, pose estimation and local minima, through the simultaneous evolution of a large number of models. Furthermore, we constrain the evolution, and thus reduce the size of the search-space, by using statistically-based deformable models whose deformations are intuitive (stretch, bulge, bend) and are driven in terms of localized principal modes of variation, instead of modes of variation across the entire shape that often fail to capture localized shape changes. Although GA are not guaranteed to achieve the global optima, our method compares favorably to the prevalent optimization techniques, convex/nonconvex gradient-based optimizers and to globally optimal graph-theoretic combinatorial optimization techniques, when applied to the task of corpus callosum segmentation in 50 mid-sagittal brain magnetic resonance images.

Ocular findings in pediatric patients with partial agenesis of corpus callosum

PURPOSE

To evaluate the ocular associations with corpus callosum agenesis.

METHODS

All children who had corpus callosum agenesis diagnosed by computed tomography or magnetic resonance imaging scans during a 10-year period were included in the study. A complete ophthalmological assessment was undertaken. Data were collected for age, sex, neurological findings, visual acuity, refractive errors, ocular motility defects, and ocular abnormalities. There were no children with Aicardi syndrome in the study.

RESULTS

Nineteen children with corpus callosum agenesis were identified, of whom 13 were examined. All had partial agenesis of the corpus callosum. Visual acuity was better than 20/60 in 5 children (38%), between 20/60 and 20/200 in 3 children (23%), and less than 20/200 in 5 children (38%). Refractive errors were present in 8 children (62%), strabismus in 6 children (46%), nystagmus in 2 children (15%), hypoplastic discs in 3 children (23%), and microphthalmos in 1 child (8%).

CONCLUSION

Non-syndromic corpus callosum agenesis may be associated with several ocular defects. Poor visual acuity, refractive errors, and strabismus predominate and need to be appropriately addressed to optimize visual function in these children. Global developmental delay (62%) and epilepsy (46%) were the most common neurological associations in this series.

Prenatal diagnosis of a partial trisomy 13q (q14-->qter): phenotype, cytogenetics and molecular characterization by spectral karyotyping and array comparative genomic hybridization

Partial trisomy 13q is an uncommon chromosomal abnormality with variable phenotypic expression. We report prenatal diagnosis of partial trisomy 13q in a fetus with partial agenesis of the cerebellar vermis, partial agenesis of the corpus callosum, hydrops and polyhydramnios. G-banding karyotyping, spectral karyotyping and array comparative genomic hybridization (aCGH) analysis of fetal blood were performed. Cytogenetic analysis of fetal blood displayed 46,XX,add(4)(q28). The parental karyotypes were normal. A girl was delivered at 34 weeks gestation; she died within 2 h. Autopsy confirmed all the prenatal findings and also showed agenesis of the diaphragm. Spectral karyotyping identified the additional material's origin as chromosome 13. aCGH was carried out and showed amplification of distal regions of the long arm of chromosome 13 from region 13q14 to qter. This is the first report of a fetus with molecular characterization of a partial trisomy 13q (q14-->qter), present as a de novo unbalanced translocation at chromosome 4q. This case demonstrates the usefulness of molecular characterization of malformed fetuses for prenatal diagnosis and counseling.

Agenesis of the corpus callosum in California 1983-2003: a population-based study

The objective of this study was to characterize the prevalence, demographic risk factors, and malformations associated with agenesis and hypoplasia of the corpus callosum diagnosed in infancy. Using a large population-based registry of birth defects, we ascertained 630 cases of agenesis (ACC) and hypoplasia (HCC) of the corpus callosum diagnosed in the first year of life among 3.4 million live births from 1983 to 2003. Infants with destructive lesions or specific complex central nervous system (CNS) malformations (neural tube defects, lissencephaly, and holoprosencephaly) were excluded. Multivariable Poisson regression analysis was used to examine demographic risk factors. The combined prevalence of ACC and HCC was 1.8 per 10,000 live births. Fifty-two percent of cases were male. Infants with ACC had an almost fourfold higher prevalence among infants born prematurely when compared with children born > or =37 weeks gestation (RR 3.7, 95% CI 2.5-5.3). After adjusting for paternal age, advanced maternal age >/=40 years was associated with ACC in infants with a chromosomal disorder (ACC RR 5.9; 95% CI 1.8-19.3, HCC RR 3.5; 95% CI 0.9-14.1). Paternal age was not significantly associated with ACC after adjusting for maternal age. Callosal anomalies were often seen in the context of a chromosomal abnormality (17.3%) and with accompanying somatic (musculoskeletal 33.5% and cardiac 27.6%) and CNS malformations (49.5%). Callosal anomalies form a clinically significant and relatively frequent group of malformations of the CNS that are associated with increased risk of premature birth, are more common with advanced maternal age and are frequently part of a complex, multisystem disorder.

Corpus callosum aplasia in a young patient with a parathyroid adenoma

A young man with primary hyperparathyroidism due to a parathyroid adenoma and aplasia of the corpus callosum is presented. We hypothesize a possible genetic association of the two pathologies: a proportion of the sporadic parathyroid adenomas are associated with genetic abnormalities of chromosome 11 and in some cases of corpus callosum aplasia, aneuploidy or polyploidy of this chromosome has been described.

Corpus callosum size in children with spastic cerebral palsy: relationship to clinical outcome

This study examines corpus callosum pathology in children with spastic cerebral palsy aged 7 to 15 years and to investigates the relation between corpus callosum areas and clinical picture. Magnetic resonance images of 46 patients were reviewed prospectively. Twenty-two patients with cerebral palsy were age and gender matched with the control patients. The cerebral palsy group had a significantly smaller mean corpus callosum surface area than did the control group. The cerebral palsy group also had a significantly smaller mean internal skull surface area measurement than did the control group. The corpus callosum/internal skull surface area ratio was also smaller for those with cerebral palsy. Wechsler Intelligence Scale Verbal IQ scores were associated with the surface area of the corpus callosum in cerebral palsy patients. A significant relationship between corpus callosum surface area and IQ scores in children with cerebral palsy was found. A positive correlation between internal skull surface area and IQ scores in children with cerebral palsy was noted. A significant correlation between Apgar score and corpus callosum surface area in the cerebral palsy group was found. A negative correlation between corpus callosum surface area and the Gross Motor Function Classification System in patients with cerebral palsy was noted.

Health-related issues in individuals with agenesis of the corpus callosum

OBJECTIVES

To explore and compare the prevalence and expression of specific health-related variables in a large survey sample of persons with agenesis of the corpus callosum (ACC) and their siblings.

METHODS

Caregiver surveys of individuals with ACC (n=189) and their siblings (n=189) provided data regarding diagnoses, physical features, neurological and sensory information, feeding, elimination and sleep concerns, and some behavioural features.

RESULTS

Compared with their siblings, individuals with ACC had more concurrent conditions and were more likely to have altered pain perception and sensitivity to touch. In addition, individuals with ACC had more sensory deficits and abnormalities as well as altered patterns of feeding/eating, elimination and sleep.

CONCLUSIONS

These data raise important questions for future research and suggest the need for increased vigilance by caregivers and health-care professionals of individuals with callosal disorders. Early detection and intervention may help prevent or ameliorate health problems in this population.

Hump-shaped corpus callosum

Developmental anomalies of the corpus callosum are agenesis, hypogenesis, or hypoplasia. In this case, a hump-shaped anomaly was present in the body of the corpus callosum. The rostrum, genu, and splenium of the corpus callosum were normal. In addition, a split was present within this hump, connecting the lateral ventricles. No additional anomalies were present. This type of anomaly has not been previously reported in the literature.

Agenesis of the corpus callosum is associated with feeding difficulties

Our objective was to characterize the common occurrence of feeding and swallowing disorders noticed by our speech therapy department among patients with agenesis of the corpus callosum. All patients with suspected or presumed agenesis of the corpus callosum undergoing therapy for feeding and/or swallowing disorders, including oral and/or pharyngeal dysphagia and oral-sensory disorder, were identified. Their brain magnetic resonance imaging (MRI) studies and charts were reviewed in detail. Seven patients with striking oral-motor and oral-sensory disorder met the criteria for agenesis of the corpus callosum. Particular difficulties noted include oral-sensory defensiveness in five of these seven patients, oral dysphagia/weakness in all seven patients, and pharyngeal dysphagia with risk of aspiration in three of these seven patients. The oral-motor weakness observed in all of the patients affected the strength and coordination necessary for functional oral-phase swallowing. We conclude that feeding and swallowing disorders are significant in children with agenesis of the corpus callosum. Although the pathophysiologic mechanism is not known, recognition of this phenomenon is important because early detection and intervention can facilitate functional feeding and swallowing patterns earlier in these patients, therefore avoiding the adverse and more severe disorders that can arise when dysphagias and/or oral-sensory disorder persist over extended periods of time.

Cognitive, behavioral, and psychiatric symptoms in two children with agenesis of the corpus callosum: case report

OBJECTIVE

To report two children, with normal intelligence, referred for evaluation of complex cognitive, behavioral, and psychiatric problems, in which Agenesis of Corpus Callosum (ACC) was an incidental finding.

METHOD

Case descriptions are used and a comprehensive differential diagnosis made with previous diagnoses of partial complex seizures (PCS), psychosis, anxiety, attention deficit hyperactivity disorder (ADHD), and behavior disorder.

RESULTS

Due to the presence of multiple biopsychosocial interactions a multimodal intervention including pharmacological, behavioral, psychotherapeutic, and social approaches was implemented, with good results.

CONCLUSION

These cases underscore the importance of conducting a comprehensive neuropsychiatric evaluation in children with severe behavior problems and other confusing symptoms. Since the incidence of ACC in behaviorally disturbed children, with normal intelligence, is unknown, physicians must accept that a reasonable degree of suspicion is warranted. Further studies are needed to facilitate physicians' awareness.

Congenital asymmetric crying facies and agenesis of corpus callosum

Although association of congenital asymmetric crying facies (CACF) with major congenital anomalies of central nervous system (CNS) has been described, brain magnetic resonance imaging (MRI) studies have not been reported. Two children who had CACF associated with agenesis of corpus callosum (ACC) diagnosed by MRI are described. Neurofibromatosis type 1 (NF-1) was diagnosed in one case. Both patients had developmental delay. To the best of our knowledge, only one previous case with CACF associated with ACC has been reported, but our cases are the first cases reported with the characteristic findings of ACC on MRI. Although café-au-lait spots have been described in previous cases, the coexistence of CACF and NF-1 has not previously been reported. Although these associations may be coincidental, clinicians should be aware of the potential link between these entities. Furthermore, these findings emphasize the importance of MRI studies for detecting brain anomalies in cases with CACF and suspected CNS involvement.

Deformable organisms for automatic medical image analysis

We introduce a new approach to medical image analysis that combines deformable model methodologies with concepts from the field of artificial life. In particular, we propose "deformable organisms", autonomous agents whose task is the automatic segmentation, labeling, and quantitative analysis of anatomical structures in medical images. Analogous to natural organisms capable of voluntary movement, our artificial organisms possess deformable bodies with distributed sensors, as well as (rudimentary) brains with motor, perception, behavior, and cognition centers. Deformable organisms are perceptually aware of the image analysis process. Their behaviors, which manifest themselves in voluntary movement and alteration of body shape, are based upon sensed image features, pre-stored anatomical knowledge, and a deliberate cognitive plan. We demonstrate several prototype deformable organisms based on a multiscale axisymmetric body morphology, including a "corpus callosum worm" that can overcome noise, incomplete edges, considerable anatomical variation, and interference from collateral structures to segment and label the corpus callosum in 2D mid-sagittal MR brain images.

White-matter alterations and callosal abnormalities in syndromic patients with mental retardation

The aim of this study was to evaluate the frequency of callosal abnormalities and white matter alterations in syndromic patients. The authors report on the cerebral magnetic resonance imaging (MRI) morphologic analysis of the corpus callosum and white matter in 73 normal subjects and 61 syndromic patients. The study of the corpus callosum was carried out by MRI using different morphometric methods: measurement of the dimensions of length and thickness of genu, body, and splenium; measurement of angles obtained using the sagittal plane; and application of the proportional grid of Talairach. The evaluation of the white matter was carried out by applying a subjective grading scale. Abnormalities of the corpus callosum were found in about 50% of the syndromic subjects; in half of these cases, the abnormalities were associated with white matter alterations. In five syndromic patients (8.2%), the white matter alterations were not associated with corpus callosum abnormalities. This study shows that corpus callosum abnormalities are frequent in syndromology regardless of the syndrome type.

Human brain malformations and their lessons for neuronal migration

The developmental steps required to build a brain have been recognized as a distinctive sequence since the turn of the twentieth century. As marking tools for experimental embryology emerged, the cellular events of cortical histogenesis have been intensively scrutinized. On this rich backdrop, molecular genetics provides the opportunity to play out the molecular programs that orchestrate these cellular events. Genetic studies of human brain malformation have proven a surprising source for finding the molecules that regulate CNS neuronal migration. These studies also serve to relate the significance of genes first identified in murine species to the more complex human brain. The known genetic repertoire that is special to neuronal migration in brain has rapidly expanded over the past five years, making this an appropriate time to take stock of the emerging picture. We do this from the perspective of human brain malformation syndromes, noting both what is now known of their genetic bases and what remains to be discovered.