Genetic etiology of agenesis of the corpus callosum: a retrospective single-center cohort analysis of 114 fetuses.

PURPOSE: The identification and prognosis of the agenesis of the corpus callosum (ACC) for prenatal consultation are complex and currently unclear. This study aims to explore the correlated genetic mutations of prenatal ACC. METHODS: We retrospectively analyzed 114 prenatal cases of ACC. All cases (n = 114) were subjected to chromosomal microarray analysis (CMA), and 66 CMA-negative cases underwent prenatal exome sequencing (pES) for further analysis. RESULTS: CMA was diagnosed positively in 15/114 (13.2%) cases and pES was diagnosed positively in 24/66 (36.4%) CMA-negative cases. The detection rate of genetic causes between complete and partial ACCs was not significantly different (P > 0.05). Between isolated and non-isolated (other anomalies present) ACCs, the diagnostic rate of pES in non-isolated cases was significantly higher (P < 0.001), while CMA results did not differ (P > 0.05). The diagnostic rate of CMA was significantly increased in cases combined with intracranial and extracranial malformations (P = 0.014), while no CMA positivity was detected in cases combined with only intracranial malformations. CONCLUSION: For fetuses with prenatal ACC, further pES analysis should be recommended after negative CMA results. Chromosome abnormalities are less likely to occur when ACC with only intracranial malformations combined.

Interhemispheric coherence of EEG rhythms in children: Maturation and differentiation in corpus callosum dysgenesis.

OBJECTIVES: To evaluate the evolution of interhemispheric coherences (ICo) in background and spindle frequency bands during childhood and use it to identify individuals with corpus callosum dysgenesis (CCd). METHODS: A monocentric cohort of children aged from 0.25 to 15 years old, consisting of 13 children with CCd and 164 without, was analyzed. The ICo of background activity (ICOBckgrdA), sleep spindles (ICOspindles), and their sum (sICO) were calculated. The impact of age, gender, and CC status on the ICo was evaluated, and the sICO was used to discriminate children with or without CCd. RESULTS: ICOBckgrdA, ICOspindles and sICO increased significantly with age without any effect of gender (p < 10-4), in both groups. The regression equations of the different ICo were stronger, with adjusted R2 values of 0.54, 0.35, and 0.57, respectively. The ICo was lower in children with CCd compared to those without CCd (p < 10-4 for all comparisons). The area under the precision recall curves for predicting CCd using sICO was 0.992 with 98.9 % sensitivity and 87.5 % specificity. DISCUSSION: ICo of spindles and background activity evolve in parallel to brain maturation and depends on the integrity of the corpus callosum. sICO could be an effective diagnostic biomarker for screening children with interhemispheric dysfunction.

Aicardi syndrome in a Nigerian female child: A case report and literature review of a rare neuro-developmental disorder from North-Western Nigeria.

Aicardi syndrome is a very rare neurodevelopmental disorder, inherited as an X-linked dominant condition with a triad of infantile spasm, partial or complete agenesis of the corpus callosum, and chorio-retinal "lacunae." We report a case of a female infant with the classical triad of Aicardi syndrome. A female infant presented to the Paediatric Neurology Clinic of the Federal Medical Centre Birnin-Kebbi, North-western Nigeria, at the age of two months with complaints of recurrent afebrile convulsions typical for infantile spasms. The patient was delivered at term with normal Apgar scores and anthropometry. Examination revealed an infant with no dysmorphic features and normal systemic examination. Magnetic Resonance Imaging (MRI) of the brain however, showed complete agenesis of the corpus callosum and dilatation of the posterior horn of the lateral and third ventricles. Fundoscopy showed multiple yellowish spots along the vascular arcades in the right eye. The left eye had a one-disc diameter lacuna in the superior nasal quadrant adjacent to the optic disc with multiple yellowish spots. A diagnosis of Aicardi syndrome was made. The child was placed on oral phenobarbital and followed up. At the age of 18 months, the child can only sit without support, hold an object in each hand, smile socially, and babble. The frequency of the seizures had also reduced from >100 episodes per day to 2-3 episodes per day, but the child had developed right-sided spastic hemiparesis. The patient was commenced on physiotherapy and the anti-epileptic drugs were maintained. We recommend clinicians consider Aicardi syndrome in the differential diagnosis of any child presenting with infantile spasms.

Neuropsychological profiles of children with agenesis of the corpus callosum: A scoping review.

AIM: To understand the wide variety of clinical outcomes in children with agenesis of the corpus callosum (AgCC) and examine evidence for the proposed neuropsychological syndrome reported in adults with primary AgCC. METHOD: PsycINFO, PsycArticles, Medline, Embase, and Web of Science (January 2007-November 2021) were searched to identify studies reporting on cognitive or neuropsychological outcome in children with AgCC aged up to 18 years. Twenty-three articles investigating the cognitive profile were found; their methodology was evaluated against quality criteria. RESULTS: While there was a high degree of heterogeneity across studies, including the methodological quality, there was evidence for some features of the neuropsychological syndrome in children with AgCC. Vulnerabilities in executive function and social cognition were found, with particular difficulties on complex and novel tasks. INTERPRETATION: Data on the neuropsychological outcomes in children with AgCC are limited. Broad assessments are necessary to determine the extent to which core features of the neuropsychological syndrome may characterize children with AgCC and how additional neuroanatomical features contribute to outcome.

Social anxiety disorder in an adolescent with agenesis of the corpus callosum: a case report.

BACKGROUND: The agenesis of corpus callosum (ACC) could impair the connectivity of the hemispheres of the cerebral cortex and cause cognitive impairments, social and behavioral issues, and even psychiatric disorders. Although social deficits are common in ACC patients, it is rare for a social anxiety disorder to occur. CASE PRESENTATION: To report a 17-year-old adolescent with complete ACC associated with social anxiety disorder, depression, impulsive behavior, and other neurodevelopmental defects such as intellectual disabilities. His avoidance and fear were improved after treatment with sertraline. CONCLUSIONS: This is the first report of social anxiety disorder in ACC patients. The possible relationship between brain structural abnormities and anxiety syndrome should be investigated in more studies.

A Novel nonsense variant in the CDH2 gene associated with ACOGS: A case report.

Agenesis of Corpus Callosum, Cardiac, Ocular, and Genital Syndrome (ACOGS; OMIM #618929) is a rare genetic disorder characterized by global developmental delay, agenesis or hypoplasia of corpus callosum, craniofacial dysmorphism, ocular, cardiac, and genital anomalies. ACOGS is caused by variations in the CDH2 gene. Our patient had a novel finding besides the classical findings of ACOGS. To the best of our knowledge, only 14 patients with ACOGS have been reported. Here, we reported the fifteenth patient with ACOGS, having a novel de novo nonsense variant in the CDH2 gene, and the first patient from Turkey with a novel finding. Our patient was the first female to have a renal anomaly since only genital malformations were reported in male patients (cryptorchidism, micropenis) so far.

Neuropsychological functioning in dysgenesis of the corpus callosum with colpocephaly.

Dysgenesis of the corpus callosum is a rare developmental abnormality in brain structure that is associated with changes in physical appearance, as well as behavioral and cognitive consequences. A relatively commonly co-occurring structural abnormality with callosal dysgenesis is colpocephaly, characterized by enlargement of the posterior lateral ventricles and reductions in posterior brain volume. Although some case studies of individuals with this combination of structural malformations exist, they do not often report results of neuropsychological evaluation. Furthermore, those that do contain neuropsychological data may be of limited generalizability due to unique patient characteristics. The current manuscript overcomes these limitations by presenting the case of a 55-year-old male with callosal dysgenesis and colpocephaly identified in adulthood. The paper includes a full profile of his performance on a comprehensive neuropsychological test battery with discussion of differential diagnosis and treatment planning. Findings indicated low average intellectual abilities with deficits in processing speed, executive functions, and social cognition, consistent with expectations based on callosal dysgenesis. One surprising finding was that despite the significant posterior involvement of colpocephaly, visuospatial skills were a relative strength. The manuscript provides a clear characterization of callosal dysgenesis with colpocephaly to facilitate future clinical comparisons and set the stage for future research on this rare neuromorphological presentation.

Agenesis of the Corpus Callosum with Facial Dysmorphism and Intellectual Disability in Sibs Associated with Compound Heterozygous KDM5B Variants.

We studied a family in which the first-born child, a girl, had developmental delay, facial dysmorphism, and agenesis of the corpus callosum (ACC). The subsequent pregnancy was interrupted as the fetus was found to be also affected by ACC. Both cases were heterozygous for two KDM5B variants predicting p (Ala635Thr) and p (Ser1155AlafsTer4) that were shown to be in trans. KDM5B variants have been previously associated with moderate to severe developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), and dysmorphism in a few individuals, but the pathogenetic mechanisms are not clear yet as patients with both monoallelic and biallelic variants have been observed. Interestingly, one individual has previously been reported with ACC and severe ID in association with biallelic KDM5B variants. Together with the observations in this family, this suggests that agenesis of the corpus callosum may be part of the phenotypic spectrum associated with KDM5B variants and that the KDM5B gene should be included in gene panels to clarify the etiology of ACC both in the prenatal and postnatal setting.

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.

[Cancer in children with intellectual disabilities: Questioning and ethical issues]. / Cancer chez un enfant porteur de handicap intellectuel : questionnement et enjeux éthiques.

The Parents and Caregivers group in the face of ethics in pediatrics of the Île-de-France Ethics Area wondered about the association of the words Disability and Cancer by focusing on the study of the course of children with intellectual disability, treated for cancer. These situations are exceptional, the number of cases in France must not be more than fifty per year. We gathered the testimony of five families of children using a semi-directive survey taking up the journey from birth, announcement of the handicap, the diagnosis of cancer and its treatment. The verbatim show that each story is unique and rich in lessons, despite the feeling of "double penalty": "He did not deserve this, a handicap plus cancer is a lot for one person", "the shot moreover." A healthcare team was also interviewed and raised an additional question: "First, the double penalty… then, what's the point?" Through these testimonies, we sought to question the ethical principles of care, which can be shaken up in these extraordinary supported.

Ophthalmic findings as clues for early diagnosis of Vici syndrome in a neonate.

AIM: To report the earliest diagnosis of Vici syndrome in a three-week-old Omani girl. METHODS: A three-week-old baby girl with blond hair and agenesis of the corpus callosum was born to consanguineous parents. An older sibling with similar findings had died at the age of six months with recurrent seizures and aspiration pneumonia without a diagnosis of the underlying systemic condition. After a standard ophthalmic and comprehensive systemic evaluation, full sequencing of the EPG5 gene was carried out. RESULTS: The findings of bilateral anterior polar cataracts and oculocutaneous albinism in the child with agenesis of corpus callosum raised a suspicion of Vici syndrome. Immunology, neurology, cardiology, and genetic consultations were requested and revealed the presence of immunodeficiency, psychomotor retardation, and hypertrophic cardiomyopathy. Full sequencing of the EPG5 gene led to the detection of a homozygous c.6084 G > A (Trp2028Ter) mutation, confirming the diagnosis of Vici syndrome. Parental heterozygosity was confirmed. On follow-up, progressive microcephaly, failure to thrive, and significant developmental delay were noted, and a clinical decision not to resuscitate was made at the age of 22 months. CONCLUSIONS: We report the earliest diagnosis of Vici syndrome in the literature. Ophthalmic findings are a cardinal feature of this condition. The diagnosis should be considered in infants with hallmark features of oculocutaneous albinism, cataracts, and agenesis of the corpus callosum. Vici syndrome has a very poor prognosis due to progressive neuroregression superimposed on the neurodevelopmental anomaly.

Comprehensive genetic analysis confers high diagnostic yield in 16 Japanese patients with corpus callosum anomalies.

Corpus callosum anomalies (CCA) is a common congenital brain anomaly with various etiologies. Although one of the most important etiologies is genetic factors, the genetic background of CCA is heterogenous and diverse types of variants are likely to be causative. In this study, we analyzed 16 Japanese patients with corpus callosum anomalies to delineate clinical features and the genetic background of CCAs. We observed the common phenotypes accompanied by CCAs: intellectual disability (100%), motor developmental delay (93.8%), seizures (60%), and facial dysmorphisms (50%). Brain magnetic resonance imaging showed colpocephaly (enlarged posterior horn of the lateral ventricles, 84.6%) and enlarged supracerebellar cistern (41.7%). Whole exome sequencing revealed genetic alterations in 9 of the 16 patients (56.3%), including 8 de novo alterations (2 copy number variants and variants in ARID1B, CDK8, HIVEP2, and TCF4) and a recessive variant of TBCK. De novo ARID1B variants were identified in three unrelated individuals, suggesting that ARID1B variants are major genetic causes of CCAs. A de novo TCF4 variant and somatic mosaic deletion at 18q21.31-qter encompassing TCF4 suggest an association of TCF4 abnormalities with CCAs. This study, which analyzes CCA patients usung whole exome sequencing, demonstrates that comprehensive genetic analysis would be useful for investigating various causal variants of CCAs.

Incidence and patterns of abnormal corpus callosum in fetuses with isolated spina bifida aperta.

OBJECTIVE: To determine the incidence and characterise corpus callosum (CC) abnormalities in fetuses with spina bifida aperta (SBA) between 18 and 26 weeks of gestation. METHODS: This was a retrospective study on fetuses with isolated SBA and who were assessed for fetal surgery. Digitally stored ultrasound images of the brain were reviewed for the presence/absence of the CC, and the length and diameter of its constituent parts (rostrum, genu, body and splenium). We used regression analysis to determine the relationship between CC abnormalities and gestational age, head circumference, ventricle size, lesion level and lesion type. RESULTS: Nearly three-quarters of fetuses with isolated SBA had an abnormal CC (71.7%, 76/106). Partial agenesis was most common in the splenium (18.9%, 20/106) and the rostrum (13.2%, 14/106). The most common abnormal pattern was of a short CC with normal diameter throughout. Of note, 20.8% (22/106) had a hypoplastic genu and 28.3% (30/106) had a thick body part. Larger lateral ventricle size was associated with partial agenesis of the CC (odds ratio [OR]: 0.14, p < 0.001) and inversely associated with a shorter CC (OR: 2.60, p < 0.01). CONCLUSION: An abnormal CC is common in fetuses with isolated SBA who are referred for fetal surgery.

X-linked partial corpus callosum agenesis with mild intellectual disability: identification of a novel L1CAM pathogenic variant.

Pathogenic variants in L1CAM, the gene encoding the L1 cell adhesion molecule, are responsible for a wide clinical spectrum including X-linked hydrocephalus with stenosis of the Sylvius aqueduct, MASA syndrome (mental retardation, aphasia, shuffling gait, adducted thumbs), and a form of spastic paraplegia (SPG1). A moderate phenotype with mild intellectual disability (ID) and X-linked partial corpus callosum agenesis (CCA) has only been related to L1CAM in one family. We report here a second family, including 5 patients with mild to moderate ID and partial CCA without signs usually associated with L1CAM pathogenic variations (such as hydrocephalus, pyramidal syndrome, thumb adductus, aphasia). We identified a previously unreported c.3226A > C transversion leading to a p.Thr1076Pro amino acid substitution in the fifth fibronectin type III domain (FnIII) of the protein which co-segregates with the phenotype within the family. We performed in vitro assays to assess the pathogenic status of this variation. First, the expression of the novel p.Thr1076Pro mutant in COS7 cells resulted in endoplasmic reticulum (ER) retention and reduced L1CAM cell surface expression, which is expected to affect both L1CAM-mediated cell-cell adhesion and neurite growth. Second, immunoblotting techniques showed that the immature form of the L1CAM protein was increased, indicating that this variation led to a lack of maturation of the protein. ID associated with CCA is not a common clinical presentation of L1CAM pathogenic variants. Genome-wide analyses will identify such variations and it is important to acknowledge this atypical phenotype.

Chudley-McCullough Syndrome: A Recognizable Clinical Entity Characterized by Deafness and Typical Brain Malformations.

Chudley-McCullough syndrome, a rare autosomal recessive disorder due to pathogenic variants in the GPSM2 (G-protein signaling modulator 2) gene, is characterized by early-onset sensorineural deafness and a typical combination of brain malformations, including ventriculomegaly, (partial) agenesis of the corpus callosum, cerebellar dysplasia, arachnoid cysts, frontal subcortical heterotopia, and midline polymicrogyria. When hearing loss is managed early, most patients have minor or no impairment of motor and cognitive development, despite the presence of brain malformations. We report 2 cases of Chudley-McCullough syndrome, one presenting with congenital deafness and normal development except for speech delay and one presenting prenatally with ventriculomegaly and an atypical postnatal course characterized by epileptic spasms, deafness, and moderate intellectual disability. These highlight the challenges faced by clinicians when predicting prognosis based on pre- or postnatal imaging of brain malformations. We have also reviewed the phenotype and genotype of previous published cases to better understand Chudley-McCullough syndrome.

3D facial morphometry in Italian patients affected by Aicardi syndrome.

Aicardi syndrome (AIC) is a rare congenital neurodevelopmental disorder of unknown etiology, that affects almost exclusively females, originally characterized by corpus callosum agenesis, chorioretinal lacunae, and infantile spasms. The current diagnostic criteria also include qualitative facial features (prominent premaxilla, upturned nasal tip, decreased nasal bridge angle, sparse lateral eyebrows, and microphthalmia) that still need quantification. A three-dimensional (3D) photogrammetric assessment of 11 Italian females, age 7-32 years, who satisfied AIC criteria, was performed. Linear distances and angles were computed from soft-tissue facial landmarks coordinates. The z-score values were calculated using data of 850 healthy reference females matched for age and compared by Mann-Whitney test (p < .01). Patients showed a shorter philtrum and right side orbital height (mean z-scores: -1.7, -0.9), shorter superior, middle, and inferior facial depths (mean z-scores: -1.3, -2.2, -2.3), and a smaller length of mandibular ramus (mean z-score: -2.1); conversely, they showed larger nasal and lower facial widths, and lower facial convexity (mean z-scores: 1.7, 1.4, 2.4). The inclinations of the orbit versus the true horizontal were increased bilaterally (mean z-scores: 1.8, 1.1). Some common facial abnormalities were quantified in AIC patients using a noninvasive instrument. They may help clinicians in performing a definite AIC diagnosis in atypical or doubt cases.