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.

Exploring the association between congenital vertebral malformations and neural tube defects.

Congenital vertebral malformations (CVMs) and neural tube defects (NTDs) are common birth defects affecting the spine and nervous system, respectively, due to defects in somitogenesis and neurulation. Somitogenesis and neurulation rely on factors secreted from neighbouring tissues and the integrity of the axial structure. Crucial signalling pathways like Wnt, Notch and planar cell polarity regulate somitogenesis and neurulation with significant crosstalk. While previous studies suggest an association between CVMs and NTDs, the exact mechanism underlying this relationship remains unclear. In this review, we explore embryonic development, signalling pathways and clinical phenotypes involved in the association between CVMs and NTDs. Moreover, we provide a summary of syndromes that exhibit occurrences of both CVMs and NTDs. We aim to provide insights into the potential mechanisms underlying the association between CVMs and NTDs, thereby facilitating clinical diagnosis and management of these anomalies.

Overlapping cortical malformations in patients with pathogenic variants in GRIN1 and GRIN2B.

BACKGROUND: Malformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants in GRIN1 or GRIN2B, genes which encode for subunits of the N-methyl-D-aspartate receptor (NMDAR). The aim of this study was to further define the phenotypic spectrum of NMDAR-related MCDs. METHODS: We report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants in GRIN1 are presented. We report the clinical and neuropathological features of one additional individual with homozygous pathogenic variants in GRIN1. RESULTS: Heterozygous variants in GRIN1 and GRIN2B were associated with overlapping severe clinical and imaging features, including global developmental delay, epilepsy, diffuse dysgyria, dysmorphic basal ganglia and hippocampi. Neuropathological examination in two fetuses with heterozygous GRIN1 variants suggests that proliferation as well as radial and tangential neuronal migration are impaired. In addition, we show that neuronal migration is also impaired by homozygous GRIN1 variants in an individual with microcephaly with simplified gyral pattern. CONCLUSION: These findings expand our understanding of the clinical and imaging features of the 'NMDARopathy' spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.

New insights into CC2D2A-related Joubert syndrome.

PURPOSE: In this study, we describe the phenotype and genotype of the largest cohort of patients with Joubert syndrome (JS) carrying pathogenic variants on one of the most frequent causative genes, CC2D2A. METHODS: We selected 53 patients with pathogenic variants on CC2D2A, compiled and analysed their clinical, neuroimaging and genetic information and compared it to previous literature. RESULTS: Developmental delay (motor and language) was nearly constant but patients had normal intellectual efficiency in 74% of cases (20/27 patients) and 68% followed mainstream schooling despite learning difficulties. Epilepsy was found in only 13% of cases. Only three patients had kidney cysts, only three had genuine retinal dystrophy and no subject had liver fibrosis or polydactyly. Brain MRIs showed typical signs of JS with rare additional features. Genotype-phenotype correlation findings demonstrate a homozygous truncating variant p.Arg950* linked to a more severe phenotype. CONCLUSION: This study contradicts previous literature stating an association between CC2D2A-related JS and ventriculomegaly. Our study implies that CC2D2A-related JS is linked to positive neurodevelopmental outcome and low rate of other organ defects except for homozygous pathogenic variant p.Arg950*. This information will help modulate patient follow-up and provide families with accurate genetic counselling.

X-linked variations in SHROOM4 are implicated in congenital anomalies of the urinary tract and the anorectal, cardiovascular and central nervous systems.

BACKGROUND: SHROOM4 is thought to play an important role in cytoskeletal modification and development of the early nervous system. Previously, single-nucleotide variants (SNVs) or copy number variations (CNVs) in SHROOM4 have been associated with the neurodevelopmental disorder Stocco dos Santos syndrome, but not with congenital anomalies of the urinary tract and the visceral or the cardiovascular system. METHODS: Here, exome sequencing and CNV analyses besides expression studies in zebrafish and mouse and knockdown (KD) experiments using a splice blocking morpholino in zebrafish were performed to study the role of SHROOM4 during embryonic development. RESULTS: In this study, we identified putative disease-causing SNVs and CNVs in SHROOM4 in six individuals from four families with congenital anomalies of the urinary tract and the anorectal, cardiovascular and central nervous systems (CNS). Embryonic mouse and zebrafish expression studies showed Shroom4 expression in the upper and lower urinary tract, the developing cloaca, the heart and the cerebral CNS. KD studies in zebrafish larvae revealed pronephric cysts, anomalies of the cloaca and the heart, decreased eye-to-head ratio and higher mortality compared with controls. These phenotypes could be rescued by co-injection of human wild-type SHROOM4 mRNA and morpholino. CONCLUSION: The identified SNVs and CNVs in affected individuals with congenital anomalies of the urinary tract, the anorectal, the cardiovascular and the central nervous systems, and subsequent embryonic mouse and zebrafish studies suggest SHROOM4 as a developmental gene for different organ systems.

A case of Aicardi-Goutières syndrome caused by TREX1 gene mutation.

Aicardi-Goutières syndrome (AGS) is a rare genetic disorder involving the central nervous system and autoimmune abnormalities, leading to severe intellectual and physical disability with poor prognosis. AGS has a phenotype similar to intrauterine viral infection, which often leads to delays in genetic counseling. In this study, we report a case with a prenatal diagnosis of AGS. The first fetal ultrasound detected bilateral lateral ventricle cystic structures, and fetal MRI was performed to identify other signs. The right parietal lobe signal showed cerebral white matter abnormalities, and fetal brain development level was lower than that of normal fetuses of the same gestational age. Whole-exome sequencing revealed that the fetus carried the TREX1:NM_033629.6:exon2:c.294dup:p. C99Mfs*3 variant, suggesting that the c.294dup mutation of the TREX1 gene was the pathogenic mutation site, and the final comprehensive diagnosis was AGS1. In this article, we also reviewed the previous literature for possible phenotypes in the fetus and found that microcephaly and intrauterine growth retardation may be the first and most important markers of the intrauterine phenotype of AGS.

Phenotypic spectrum and genomics of undiagnosed arthrogryposis multiplex congenita.

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is characterised by congenital joint contractures in two or more body areas. AMC exhibits wide phenotypic and genetic heterogeneity. Our goals were to improve the genetic diagnosis rates of AMC, to evaluate the added value of whole exome sequencing (WES) compared with targeted exome sequencing (TES) and to identify new genes in 315 unrelated undiagnosed AMC families. METHODS: Several genomic approaches were used including genetic mapping of disease loci in multiplex or consanguineous families, TES then WES. Sanger sequencing was performed to identify or validate variants. RESULTS: We achieved disease gene identification in 52.7% of AMC index patients including nine recently identified genes (CNTNAP1, MAGEL2, ADGRG6, ADCY6, GLDN, LGI4, LMOD3, UNC50 and SCN1A). Moreover, we identified pathogenic variants in ASXL3 and STAC3 expanding the phenotypes associated with these genes. The most frequent cause of AMC was a primary involvement of skeletal muscle (40%) followed by brain (22%). The most frequent mode of inheritance is autosomal recessive (66.3% of patients). In sporadic patients born to non-consanguineous parents (n=60), de novo dominant autosomal or X linked variants were observed in 30 of them (50%). CONCLUSION: New genes recently identified in AMC represent 21% of causing genes in our cohort. A high proportion of de novo variants were observed indicating that this mechanism plays a prominent part in this developmental disease. Our data showed the added value of WES when compared with TES due to the larger clinical spectrum of some disease genes than initially described and the identification of novel genes.

Evaluation of the Filum Terminale in Hereditary Equine Regional Dermal Asthenia.

The objectives of this study were to describe the anatomy, histology, and ultrastructure of the equine filum terminale (FT) and to describe the FT in hereditary equine regional dermal asthenia (HERDA), a model of human Ehlers-Danlos syndromes (EDS). Those humans suffer from tethered cord syndrome (TCS) caused by an abnormally structured FT wherein its attachment at the base of the vertebral column leads to long-term stretch-induced injury to the spinal cord. The pathophysiology of TCS in EDS is poorly understood, and there is a need for an animal model of the condition. Histopathologic and ultrastructural examinations were performed on FT from HERDA (n = 4) and control horses (n = 5) and were compared to FT from human TCS patients with and without EDS. Adipose, fibrous tissue, and neuronal elements were assessed. CD3 and CD20 immunohistochemistry was performed to clarify cell types (HERDA n = 2; control n = 5). Collagen fibrils were assessed in cross-section for fibril diameter and shape, and in longitudinal section for fibril disorganization, swelling, and fragmentation. The equine and human FT were similar, with both containing fibrous tissue, ependyma, neuropil, and nerve twigs. Hypervascularity was observed in both HERDA horses and human EDS-TCS patients and was not observed in equine or human controls. Moderate to severe abnormalities in collagen fibril orientation and architecture were observed in all HERDA horses and were similar to those observed in human EDS-TCS patients.

Anatomical implications of posterior cephaloceles in the dural venous sinuses.

OBJECTIVE: To analyze the venous anatomy of the dural sinuses of patients with posterior encephaloceles, in order to formulate anatomical patterns which can ensure safer surgery. METHODS: This is a retrospective study, analyzing eight patients diagnosed with posterior encephalocele throughout 1 year. RESULTS: Eight patients with cephaloceles were evaluated in our study from January 2017 to January 2018. The most common alteration was dysgenesis of the straight sinus (n = 7), followed by venous anomalies in the encephalocele and alterations in the SSS (superior sagittal sinus) (n = 4), and the occurrence of a falcine sinus (FC) in 3 patients. CONCLUSION: Anatomical variations are frequent in patients with cephaloceles. Therefore, an understanding of them is necessary for safe and effective treatment.

The spectrum of brainstem malformations associated to mutations of the tubulin genes family: MRI and DTI analysis.

OBJECTIVES: To describe the spectrum of brainstem malformations associated to mutations in the tubulin genes taking advantage of magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). METHODS: Fifteen patients (six males; median age, 1.25 years; range, 1 month to 31 years) with mutations in the tubulin genes (TUBA1A = 8, TUBB2B = 4, TUBB3 = 3) studied with MRI and DTI were included in the study. Brain MR exams were reviewed to describe the malformative aspects of the brainstem. Malformations of the supratentorial brain and cerebellum were also recorded. Tractography was performed in seven selected cases. RESULTS: Fourteen patients (93%) showed complex malformations of the brainstem. Most common findings, apparent on anatomical MR sequences, were brainstem asymmetry (12 cases, 5 of which with a crossed pattern characterised by a hypertrophic right medulla oblongata and hypertrophic left pons), short and small pons on midline (10 cases) and anterior brainstem clefting (6 cases). DTI revealed abnormal transverse pontine fibres (13 cases), fusion of corticospinal tracts and medial lemnisci (9 cases) and a small decussation of the superior cerebellar peduncles (7 cases). CONCLUSIONS: Conventional/anatomical MRI and DTI reveal a complex pattern of brainstem malformations associated with tubulin genes mutations. KEY POINTS: • Brainstem malformations affect 93% patients with mutated tubulin genes • MRI shows homolateral and crossed brainstem asymmetries, clefts and pons hypoplasia • DTI demonstrates irregular representation of transverse pontine fibres and fusion of corticospinal tracts.

Joubert syndrome: imaging features and illustration of a case.

BACKGROUND: Joubert Syndrome (JS) is a rare autosomal recessive disorder characterised clinically by neonatal breathing dysregulation, developmental delay, intellectual disability, hypotonia, ataxia, nystagmus. CASE REPORT: We present another case of this uncommon syndrome in a 12 years old patient presenting with classical complaints of developmental delay, intellectual impairment, weakness in both lower limbs, ataxia and abnormal facies and diagnosed on Computed Tomography. CONCLUSIONS: Joubert Syndrome should be ruled out in all patients presenting with hypotonia, ataxia, nystagmus, breathing abnormalities and developmental delay. Its neuroimaging hallmarks include molar tooth sign and batwing shaped fourth ventricle. As JS is associated with multiorgan involvement, these patients should enter a diagnostic protocol to assess systemic abnormalities. Extreme caution should be taken while administering drugs in these patients as they are prone to respiratory depression.

Classical signs and appearances in pediatric neuroradiology: a pictorial review.

Radiological practice includes classification of illnesses with similar characteristics through recognizable signs. In this report, twenty-eight important and frequently seen neuroradiological signs in childhood are presented and described using X-rays, computed tomography (CT), magnetic resonance (MR) images, illustrations and photographs.

Prenatal diagnosis and postnatal outcome of fetal intracranial hemorrhage: a single-center experience.

OBJECTIVE: To assess prenatal ultrasonographic findings and postnatal outcomes in fetuses with intracranial hemorrhage (ICH). METHODS: This retrospective study included fetuses prenatally diagnosed with ICH between December 2012 and August 2023. Maternal characteristics, prenatal ultrasonographic findings, and postnatal outcomes were reviewed. RESULTS: Twenty-seven fetuses with ICH were reviewed. Intracranial hemorrhage was classified as grade 3 and 4 in 24 fetuses. Twenty-two fetuses had ICH, four had ICH with subdural hemorrhage, and one had ICH with subarachnoid hemorrhage. Ventriculomegaly was the most common ultrasonographic finding, and was observed in 22 of the 27 (81.5%) fetuses. Seven fetuses were lost to follow-up, and four intrauterine fetal deaths occurred. The remaining 16 fetuses were delivered at a median gestational age of 35+2 weeks. The infants were followed-up for 40.1 months (range, 4-88). Nine of the 16 infants underwent ventriculoperitoneal placement. One infant underwent brain surgery for severe epilepsy. Motor impairment, including cerebral palsy, was observed in 13 infants (81.2%). Neurologic impairment occurred in six infants (37.5%), developmental delay in nine (56.2%), and epilepsy in 11 (68.7%). CONCLUSION: Fetal ICH is a rare complication diagnosed during pregnancy, which results in subsequent fetal neurological sequelae or death. This study demonstrated that the common ultrasonographic findings in fetal ICH were progressive ventriculomegaly and increased periventricular echogenicity. Fetuses diagnosed with prenatal ICH, especially those affected by higher-grade ICH, may be at an increased risk of long-term neurodevelopmental problems.

An Unusual Cause of Neck Pain and Headache in Pregnancy.

A previously healthy 21-year-old Caucasian female G1P0 at 32 weeks gestation presented to the ED for an episode of syncope. She also complained of headaches, neck pain, and blurry vision. Physical examination revealed a healthy pregnant female. Neurological examination demonstrated Grade III papilledema but was otherwise unremarkable. CT brain revealed hydrocephalus and intraventricular hemorrhage of unclear etiology MRI of the head was negative for a mass lesion. MRA/MRV of the head was negative, ruling out cavernous sinus thrombosis. Lumbar puncture was bloody but negative for infection. Infectious workup, including HSV, toxoplasmosis, and neurocysticercosis, was negative. An intraventricular drain was placed for hydrocephalus. While in the hospital, she developed sudden left-sided weakness, prompting an emergency C-section. Further workup with CT angio of the brain and neck revealed an arteriovenous malformation (AVM) involving the anterior spinal artery and adjacent venous plexus. Digital subtraction angiography showed a C2-3 pial AVM with a partially thrombosed nidal aneurysm. She was transferred to an outside hospital for embolization. Embolization obliterated the aneurysm, but residual flow remained in the AVM. Blood products are visible on sagittal MRI after embolization. At hospital discharge, her left-sided weakness had resolved, and her neurological examination was normal. The hydrocephalus had resolved.

Epidemiological trends of isolated and non-isolated central nervous system congenital malformations in live births in a middle-income setting.

OBJECTIVES: This study aimed to analyze, in the São Paulo state of Brazil, time trends in prevalence, neonatal mortality, and neonatal lethality of central nervous system congenital malformations (CNS-CM) between 2004 and 2015. METHODS: Population-based study of all live births with gestational age ≥22 weeks and/or birthweight ≥400 g from mothers living in São Paulo State, during 2004-2015. CNS-CM was defined by the presence of International Classification Disease 10th edition codes Q00-Q07 in the death and/or live birth certificates. CNS-CM was classified as isolated (only Q00-Q07 codes), and non-isolated (with congenital anomalies codes nonrelated to CNS-CM). CNS-CM associated neonatal death was defined as death between 0 and 27 days after birth in infants with CNS-CM. CNS-CM prevalence, neonatal mortality, and lethality rates were calculated, and their annual trends were analyzed by Prais-Winsten Model. The annual percent change (APC) with 95% confidence interval (95%CI) was obtained. RESULTS: 7,237,628 live births were included in the study and CNS-CM were reported in 7526 (0.1%). CNS-CM associated neonatal deaths occurred in 2935 (39.0%). Isolated CNS-CM and non-isolated CNS-CM were found respectively in 5475 and 2051 livebirths, with 1525 (28%) and 1410 (69%) neonatal deaths. CNS-CM prevalence and neonatal lethality were stationary, however neonatal mortality decreased (APC -1.66; 95%CI -3.09 to -0.21) during the study. For isolated CNS-CM, prevalence, neonatal mortality, and lethality decreased over the period. For non-isolated CNS-CM, the prevalence increased, neonatal mortality was stationary, and lethality decreased during the period. The median time of CNS-CM associated neonatal deaths was 18 h after birth. CONCLUSIONS: During a 12-year period in São Paulo State, Brazil, neonatal mortality of infants with CNS-CM in general and with isolated CNS-CM showed a decreasing pattern. Nevertheless CNS-CM mortality remained elevated, mostly in the first day after birth.

Application of Ultrasonic Doppler Technology Based on Wavelet Threshold Denoising Algorithm in Fetal Heart Rate and Central Nervous System Malformation Detection.

This paper discusses the clinical value of standardized early pregnancy ultrasound structure screening in the diagnosis of fetal central nervous system (CNS) malformations. In this paper, 6902 cases (8336 fetuses) of 11～13 + 6 weeks of gestation (5468 cases of singleton pregnancy and 1434 cases of twin pregnancy) underwent standardized early pregnancy ultrasound structure screening. While tracking the pregnancy process and clinical outcome, we found that 13 cases of CNS malformations (10 cases of single pregnancy, 3 cases of twin pregnancy) were detected by prenatal ultrasound in 6902 cases (8336 fetuses) 11～13 + 6 weeks of gestation including 5 cases of exposed brain malformations. There were 4 cases of children with cerebral sickle disease, 2 cases of forebrain without splitting, 1 case of meningocele, and 1 case of open spina bifida. There were 4 cases with other structural abnormalities and 3 cases with abnormal karyotype. Follow-up results of 13 fetuses indicated that except for 3 cases of twin malformed fetuses who continued to be pregnant after selective reduction, ultrasound results of the remaining fetuses were consistent with autopsy results after the induction of labor. For this reason, it can be concluded that standardized ultrasound structural screening during early pregnancy can detect fetal CNS malformations early and has important clinical value in reducing the birth rate of malformed fetuses and guiding obstetric treatment.

A Complex Cortical Malformation Caused by a Mutation in the Tubulin-Encoding TUBB3 Gene.

Tubulinopathy commonly refers to complex congenital and non-progressive brain malformations caused by mutations in the tubulin genes. Among tubulin-encoding genes, TUBB3 has rarely been reported as a cause of complex cortical malformations. Herein, we report a case of tubulinopathy in a 21-month-old boy who presented with delayed development. He could not walk on his own and was not able to speak more than five words. Physical examination revealed right esotropia and hypotonia of the lower extremities. MRI showed dysmorphic brainstem and dysmorphic and hypertrophic basal ganglia. The right thalamus was relatively smaller than the left one. The cerebellum showed disorganization of the cerebellar folia. DNA sequencing revealed a missense mutation of the TUBB3 gene.

Diagnosis of fatal central nervous system malformations based on prenatal colour doppler ultrasound.

OBJECTIVE: Fatal central nervous system (CNS) malformation is one of the most common congenital malformations, and is an important cause of infant mortality. Ultrasound diagnostic technology has the advantages of fast, safe, economic, convenient and real-time dynamic imaging, and it is the first choice for imaging diagnosis of the foetus. This paper studies the diagnosis of fatal central nervous system malformations based on prenatal Doppler ultrasound, and further accumulates clinical experience for prenatal diagnosis. METHODS: 320 pregnant women who underwent prenatal diagnosis in our hospital from August 2017 to December 2018. Ultrasound showed abnormal fatal craniocerebral development and MRI examination of fatal cranial brain was performed on the same day or the next day. The PHILIPS IU22 colour Doppler ultrasound system was used to scan pregnant women. Ultrasound showed 320 cases of fatal craniocerebral abnormalities and MRI diagnosis on the same day or the next day, of which 122 cases were consistent with MRI results, accounting for 38%; 173 cases were supplemented with MRI diagnostic information, accounting for 54%; MRI corrected diagnostic information There were 16 cases, accounting for 5%; 9 cases were abnormal, but 3 cases were not revealed by MRI. CONCLUSION: Ultrasound examination during pregnancy has a high detection rate for the diagnosis of fatal CNS malformations. As the preferred imaging method for prenatal diagnosis, it is essential for timely and early screening of fatal malformations. MRI has a higher diagnostic value for fatal CNS malformations, and can play an important role in supplementing and misdiagnosing cases that have been missed by ultrasound. Therefore, in the prenatal diagnosis, attention should be paid to combining these two inspection methods, each taking its advantages and applying it to clinical.