Cerebellar Heterotopia Research Articles

Neuroradiologic, clinic and genetic characterization of cerebellar heterotopia: a pediatric multicentric study.

Background and purpose:Cerebellar heterotopia (CH) is a neuroradiological abnormality poorly reported and investigated in the literature. It can be observed as an isolated finding, but it has been mainly reported in the context of cerebellar dysgenesis and in syndromic conditions. The aim of this study is to provide a comprehensive neuroradiological, clinical, and genetic characterization of a cohort of pediatric patients with cerebellar heterotopia.Materials and methods:Patients with a diagnosis of CH were systematically selected from the neuroimaging databases of the four Italian Centers participating in this retrospective study. For each patient, information regarding demographic, clinical, genetic and neuroradiological data were collected.Results:Thirty-two pediatric patients were recruited and subdivided into two groups: patients with isolated CH and/or cerebellar malformations (n= 18) and patients with CH associated with cerebral malformations (n=14). Isolated CH consistently showed a peripheral subcortical localization in the inferior portion of cerebellar hemispheres, with either unilateral or bilateral distribution. Ten patients belonging to the second group had a diagnosis of CHARGE syndrome, and their nodules of CH were mainly but not exclusively bilateral, symmetric, located in the peripheral subcortical zone and in the inferior portion of the cerebellar hemispheres; the remaining 4 patients of the second group, showed either bilateral or unilateral CH, located in both peripheral cortex and deep white matter and in the superior and inferior portions of cerebellum. Patients with isolated CH showed high prevalence of language development delay; neurodevelopmental disorders were the most represented clinical diagnoses. Recurring features were behavioral problems and motor difficulties. A conclusive genetic diagnosis was found in 18/32 patients.Conclusions:We found distinctive neuroradiological patterns of CH. Genetic results raise the possibility of a correlation between cerebellar morphological and functional developmental disruption, underscoring the importance of CH detection and reporting to orient the diagnostic path.Abbreviations CH Cerebellar heterotopia; MRI Magnetic resonance imaging; CC Corpus callosum; ASD autism spectrum disorder; IVH inferior vermian hypoplasia.

Neocortical and cerebellar malformations affect flurothyl-induced seizures in female C57BL/6J mice.

Brain malformations cause cognitive disability and seizures in both human and animal models. Highly laminated structures such as the neocortex and cerebellum are vulnerable to malformation, affecting lamination and neuronal connectivity as well as causing heterotopia. The objective of the present study was to determine if sporadic neocortical and/or cerebellar malformations in C57BL/6J mice are correlated with reduced seizure threshold. The inhaled chemi-convulsant flurothyl was used to induce generalized, tonic-clonic seizures in male and female C57BL/6J mice, and the time to seizure onset was recorded as a functional correlate of brain excitability changes. Following seizures, mice were euthanized, and brains were extracted for histology. Cryosections of the neocortex and cerebellar vermis were stained and examined for the presence of molecular layer heterotopia as previously described in C57BL/6J mice. Over 60% of mice had neocortical and/or cerebellar heterotopia. No sex differences were observed in the prevalence of malformations. Significantly reduced seizure onset time was observed dependent on sex and the type of malformation present. These results raise important questions regarding the presence of malformations in C57BL/6J mice used in the study of brain development, epilepsy, and many other diseases of the nervous system.

Cerebellar heterotopia of infancy in sudden infant death syndrome: an observational neuropathological study of four cases

Sudden infant death syndrome (SIDS) is the sudden unexpected death of an infant < 1 year of age that remains unexplained after comprehensive workup including complete autopsy and investigation of the circumstances of death. The triple risk hypothesis posits that SIDS results as a combination of both intrinsic and extrinsic factors on the background of a predisposing vulnerability. Neuropathological examination in the past has focussed mainly on the brainstem as the major player in respiratory control, where subtle findings have been linked to the chain of events leading to death in SIDS. The cerebellum has received less attention, probably due to an assumed negligible role in central cardiorespiratory control. We report four cases of SIDS in which neuropathological investigation revealed cerebellar heterotopia of infancy, a distinct malformation of the cerebellum, and discuss the potential impact of this condition on the aetiology and pathogenesis of SIDS.

Cerebellar Heterotopias: Expanding the Phenotype of Cerebellar Dysgenesis in CHARGE Syndrome.

Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness (CHARGE) syndrome is a multisystem developmental disorder associated with a number of well-described clinical and imaging findings, including cerebellar hypoplasia. We observed cerebellar heterotopias on MR imaging in 2 patients with CHARGE, confirmed by postmortem examination. We sought to determine the prevalence and define the characteristics of similar findings on MR imaging for a cohort of patients with CHARGE syndrome. We performed a retrospective, observational, cross-sectional study to assess the prevalence and characteristic features of cerebellar heterotopias in 35 patients with CHARGE syndrome with available brain MR imaging studies, as well as to evaluate additional features of cerebellar dysgenesis. Cerebellar heterotopias were identified in 27/35 (77%) patients with CHARGE, characteristic in both location and appearance. Additional features of cerebellar dysgenesis were present in 31/34 evaluable patients (91%), including inferior vermian hypoplasia (90%), anteromedial rotation of the inferior tonsils (90%), and disorganized foliation of the cerebellar hemispheres (74%) or superior vermis (16%). Patients with CHARGE syndrome have a high prevalence of characteristic cerebellar heterotopias and disorganized foliation and abnormal cerebellar morphology, thereby expanding the phenotype of cerebellar dysgenesis in this syndrome.

Malformation of the Posterior Cerebellar Vermis Is a Common Neuroanatomical Phenotype of Genetically Engineered Mice on the C57BL/6 Background.

C57BL/6 mice exhibit spontaneous cerebellar malformations consisting of heterotopic neurons and glia in the molecular layer of the posterior vermis, indicative of neuronal migration defect during cerebellar development. Recognizing that many genetically engineered (GE) mouse lines are produced from C57BL/6 ES cells or backcrossed to this strain, we performed histological analyses and found that cerebellar heterotopia were a common feature present in the majority of GE lines on this background. Furthermore, we identify GE mouse lines that will be valuable in the study of cerebellar malformations including diverse driver, reporter, and optogenetic lines. Finally, we discuss the implications that these data have on the use of C57BL/6 mice and GE mice on this background in studies of cerebellar development or as models of disease.

ErbB4 in Laminated Brain Structures: A Neurodevelopmental Approach to Schizophrenia.

The susceptibility genes for schizophrenia Neuregulin-1 (NRG1) and ErbB4 have critical functions during brain development and in the adult. Alterations in the ErbB4 signaling pathway cause a variety of neurodevelopmental defects including deficiencies in neuronal migration, synaptic plasticity, and myelination. I have used the ErbB4-/- HER4heart KO mice to study the neurodevelopmental insults associated to deficiencies in the NRG1-ErbB4 signaling pathway and their potential implication with brain disorders such as schizophrenia, a chronic psychiatric disease affecting 1% of the population worldwide. ErbB4 deletion results in an array of neurodevelopmental deficits that are consistent with a schizophrenic model. First, similar defects appear in multiple brain structures, from the cortex to the cerebellum. Second, these defects affect multiple aspects of brain development, from deficits in neuronal migration to impairments in excitatory/inhibitory systems, including reductions in brain volume, cortical and cerebellar heterotopias, alterations in number and distribution of specific subpopulations of interneurons, deficiencies in the astrocytic and oligodendrocytic lineages, and additional insults in major brain structures. This suggests that alterations in specific neurodevelopmental genes that play similar functions in multiple neuroanatomical structures might account for some of the symptomatology observed in schizophrenic patients, such as defects in cognition. ErbB4 mutation uncovers flaws in brain development that are compatible with a neurodevelopmental model of schizophrenia, and it establishes a comprehensive model to study the basis of the disorder before symptoms are detected in the adult.

40. Post-mortem neuropathologic findings in unverricht-lundborg disease (progressive myoclonic epilepsy type I): a case report

Unverricht-Lundborg disease (ULD) is the most common seizure disorder in the rare subgroup of progressive myoclonic epilepsies. Patients typically present between the ages of 6 and 16 with onset of stimulus and/or photosensitive myoclonus as well as generalised tonic-clonic seizures. Progressive cerebellar degeneration leads to the development of ataxia, incoordination, dysarthria and intention tremor. ULD is typified by specific mutations in the CSTB gene located at chromosome 21q22.3. While the clinical features and genetic abnormalities of this disease are well known, detailed neuropathological examination is rarely described in the published literature. We present the neuropathological findings of a genetically verified case of Unverricht-Lundborg disease in a 74 year old female. The deceased had a history of recurrent seizures and presented to hospital after an episode of status epilepticus. She subsequently passed away after presumed aspiration. At autopsy, macroscopic examination of the brain revealed mild frontotemporoparietal atrophy. The cerebellum showed marked atrophy, particularly inferiorly and dorsally. Microscopic examination of the hippocampus was unremarkable, and in particular there was no evidence of hippocampal sclerosis. Marked cerebellar atrophy was confirmed microscopically affecting the cerebellar cortex and subjacent white matter. Incidental cerebellar heterotopias were also noted.

Axonal anatomy of molecular layer heterotopia of the cerebellar vermis

C57BL/6 mice and closely related strains exhibit heterotopia in the molecular layer of folia VIII and IX of the cerebellar vermis. Previously, we demonstrated that heterotopia are composed primarily of granule cells, Golgi cells, and GABAergic interneurons and are indicative of neuronal migration defect. In the present report we use immunocytochemistry and Thy1-YFP reporter mice to reveal the axonal constituents of cerebellar heterotopia which include mossy fibers, as well as serotonergic, cholinergic, and catecholaminergic axons. These data are relevant toward understanding of the mechanisms of axonal targeting during normal and abnormal cerebellar development.

Prenatal diagnosis of the duplication 17p11.2 associated with Potocki–Lupski syndrome in a foetus presenting with mildly dysmorphic features

Duplication 17p11.2 (Potocki–Lupski syndrome (PTLS) MIM# 610883) is a genomic disorder with an estimated incidence of 1 in 25,000 births. As for other genomic disorders this duplication is typically de novo and is not associated with advanced maternal age or advanced paternal age. Herein we describe a prenatal diagnosis of duplication 17p11.2. This diagnosis was not suspected as the prenatal ultrasound findings were non-specific; however, BACs-on-Beads™ technology and array comparative genomic hybridization (aCGH) confirmed the common ∼3.7 Mb duplication. Evaluation of the foetus following termination of pregnancy revealed mildly dysmorphic features as well as congenital anomalies not previously reported in PTLS, specifically left pulmonary isomerism, an abnormally positioned left coronary orifice and nodular cerebellar heterotopia. This report exemplifies the utility of prenatal testing using new genomic technologies even when there are no multiple anomalies on foetal ultrasound. This report also exemplifies the utility of foetal autopsy in the identification of “occult” congenital anomalies.

Adult leptomeningeal cerebellar heterotopia in contact with the posterior inferior cerebellar artery

A leptomeningeal mass was encountered during microdissection of a 63-year-old male cadaver, located dorsal to the left side of the medulla oblongata. The structure was compressing the posterior inferior cerebellar artery (PICA) and was composed of cerebellar-like tissue. Immunohistochemistry for S100 protein, glial fibrillary acidic protein and neurofilaments (NF, the triplet proteins and the 200kD antibody) on paraffin-embedded samples confirmed the cerebellar heterotopion. Abundant Lewy-like degenerative bodies were also identified within the heterotopion; they were positive for the NF triplet and negative for the 200kD neurofilaments. Purkinje cells were rare. This is the first evidence of a leptomeningeal cerebellar heterotopia in contact with PICA in adult. Such subtentorial heterotopias, even if rare, should be searched for during clinical, paraclinical and surgical explorations of the posterior fossa.

A meckelin–filamin A interaction mediates ciliogenesis

MKS3, encoding the transmembrane receptor meckelin, is mutated in Meckel-Gruber syndrome (MKS), an autosomal-recessive ciliopathy. Meckelin localizes to the primary cilium, basal body and elsewhere within the cell. Here, we found that the cytoplasmic domain of meckelin directly interacts with the actin-binding protein filamin A, potentially at the apical cell surface associated with the basal body. Mutations in FLNA, the gene for filamin A, cause periventricular heterotopias. We identified a single consanguineous patient with an MKS-like ciliopathy that presented with both MKS and cerebellar heterotopia, caused by an unusual in-frame deletion mutation in the meckelin C-terminus at the region of interaction with filamin A. We modelled this mutation and found it to abrogate the meckelin-filamin A interaction. Furthermore, we found that loss of filamin A by siRNA knockdown, in patient cells, and in tissues from Flna(Dilp2) null mouse embryos results in cellular phenotypes identical to those caused by meckelin loss, namely basal body positioning and ciliogenesis defects. In addition, morpholino knockdown of flna in zebrafish embryos significantly increases the frequency of dysmorphology and severity of ciliopathy developmental defects caused by mks3 knockdown. Our results suggest that meckelin forms a functional complex with filamin A that is disrupted in MKS and causes defects in neuronal migration and Wnt signalling. Furthermore, filamin A has a crucial role in the normal processes of ciliogenesis and basal body positioning. Concurrent with these processes, the meckelin-filamin A signalling axis may be a key regulator in maintaining correct, normal levels of Wnt signalling.

The neuropathology of autism: defects of neurogenesis and neuronal migration, and dysplastic changes

Autism is characterized by a broad spectrum of clinical manifestations including qualitative impairments in social interactions and communication, and repetitive and stereotyped patterns of behavior. Abnormal acceleration of brain growth in early childhood, signs of slower growth of neurons, and minicolumn developmental abnormalities suggest multiregional alterations. The aim of this study was to detect the patterns of focal qualitative developmental defects and to identify brain regions that are prone to developmental alterations in autism. Formalin-fixed brain hemispheres of 13 autistic (4–60 years of age) and 14 age-matched control subjects were embedded in celloidin and cut into 200-μm-thick coronal sections, which were stained with cresyl violet and used for neuropathological evaluation. Thickening of the subependymal cell layer in two brains and subependymal nodular dysplasia in one brain is indicative of active neurogenesis in two autistic children. Subcortical, periventricular, hippocampal and cerebellar heterotopias detected in the brains of four autistic subjects (31%) reflect abnormal neuronal migration. Multifocal cerebral dysplasia resulted in local distortion of the cytoarchitecture of the neocortex in four brains (31%), of the entorhinal cortex in two brains (15%), of the cornu Ammonis in four brains and of the dentate gyrus in two brains. Cerebellar flocculonodular dysplasia detected in six subjects (46%), focal dysplasia in the vermis in one case, and hypoplasia in one subject indicate local failure of cerebellar development in 62% of autistic subjects. Detection of flocculonodular dysplasia in only one control subject and of a broad spectrum of focal qualitative neuropathological developmental changes in 12 of 13 examined brains of autistic subjects (92%) reflects multiregional dysregulation of neurogenesis, neuronal migration and maturation in autism, which may contribute to the heterogeneity of the clinical phenotype.

A Case of Isolated Focal Cerebellar Heterotopia in a Patient Affected by HHT: MR and MR Spectroscopy Findings

We describe the MR study of an isolated cerebellar heterotopia , incidentally found in a 17 year-old girl affected by hereditary hemorrhagic teleangectasia. Conventional MR, DWI and MR spectroscopy findings are described; at the best of our knowledge, spectroscopic findings have not been previously reported in this setting. A possible relation between a microvascular damage due to HHT and the cerebellar malformation is hypotised.

CEREBELLAR MIGRATION DEFECTS IN AICARDI SYNDROME: AN EXTENSION OF THE NEUROPATHOLOGICAL SPECTRUM

The Aicardi syndrome is characterized by infantile spasms, corpus callosum agenesis, and chorioretinal lacunae and almost exclusively affects females (very rarely, 47, XXY males). The crucial genetic mishap likely occurs in the postzygotic stage, but the variable clinical phenotype among the ∼ 450 known cases has not been explained. No consistent mutations or deletions exist among patients. We encountered a baby girl with early onset infantile spasms. She had left-sided cleft lip/palate, costovertebral defects, scoliosis, callosal agenesis, and microphthalmia. She expired at the age of 3 months of respiratory infection. On autopsy she had thoracic hemivertebrae with rib defects, bilateral microphthalmia, microcornea, posterior colobomata, abnormalities of the retinal pigment epithelium, absence of normal ganglion cells in the retina, gross asymmetry of the brain with cerebral polymicrogyria, total callosal agenesis, cerebral subcortical and subependymal nodular heterotopias, cerebellar nodular heterotopias, and tegmental/basal unilateral brainstem hypoplasia. Cerebellar and retinal migration defects have not been described before in Aicardi syndrome and may have had a bearing on this patient's eventual outcome.

Unusual split cord with neurenteric cyst and cerebellar heterotopia over spinal cord

To report a case of splitting of a cord, which could neither be classified as type I nor type II according to Pang's classification. The child had associated neurenteric cyst and cerebellar tissue heterotopia. A 3-year-old girl presented with a tuft of hair and dermal sinus at her upper dorsal spine. She had splitting of cord into two halves by two intradural horny osseocartilaginous spurs leaving a gap of 3 mm in between (two spurs and two halves of cords). A neurenteric cyst was seen passing from the anterior to posterior aspect of the cords through this gap. An associated heterotopic cerebellar tissue mass was encountered over the dorsum of cord proximal to splitting. The dermal sinus, neurenteric cyst, and spurs were excised to detether the cord. The heterotopic tissue was biopsied. The child had no neurological deficit at 2.5 years follow-up. An unusual splitting of cord by unusual spurs may leave a gap between two spurs and two halves of cords to pass a neurenteric cyst. Rarely, heterotopic tissue may be associated with split cord syndrome. A dermal sinus may lead into underlying neurenteric cyst (rather than dermoid).

Fryns syndrome: a review of the phenotype and diagnostic guidelines.

Fryns syndrome (FS) is the commonest autosomal recessive syndrome associated with congenital diaphragmatic hernia (CDH) and comprises CDH, pulmonary hypoplasia, craniofacial anomalies, distal limb hypoplasia, and internal malformations. Although there have been more than 50 case reports on probands with FS, the diagnostic guidelines were formulated from a review of eight patients and modifications to the guidelines have only once been suggested. Recently, several case reports have described new anomalies in FS and other papers have highlighted the variation in expressivity found in FS. This paper examines the medical literature on FS to define the phenotype and to review the diagnostic guidelines. We conclude that CDH with brachytelephalangy and/or nail hypoplasia is strongly suggestive of the diagnosis and that pulmonary hypoplasia, craniofacial dysmorphism, orofacial clefting, and polyhydramnios are sufficiently frequent to be diagnostically useful. Other distinctive malformations that are consistent with FS include ventricular dilatation or hydrocephalus, agenesis of the corpus callosum, neuronal or cerebellar heterotopias, abnormalities of the aorta, renal cysts, dilatation of the ureters, bicornuate uterus, renal dysplasia, proximal thumbs, and broad clavicles.

Hamartoma in the internal auditory canal

An 11 year old girl presented with hearing loss in her left ear and left trigeminal and facial nerve palsy. Radiological examinations revealed an enlargement of the left internal acoustic canal and the existence of a mass protruding from the canal into the cerebellopontine angle. The partial resection of the mass by a suboccipital craniectomy resulted in ceasing the progression of her symptoms. Histological diagnosis was hamartoma with cerebellar heterotopia. The concurrence of heterotopic cerebellar tissue could help to understand the pathogenesis of hamartomas.

Congenital malformations and chromosomal aberrations.

Among a great number of chromosomal aberrations, the absence of cerebral malformations does not explain the reason for mental retardation and will lead to interpreting as normal the echography of a fetus which, after birth, will be revealed to have a trisomy. Trisomic brain anomalies are not constant or obligatory, but some of them (holoprosencephaly for 61% of trisomy-13 and agenesis of corpus callosum for 8% of trisomy-18) have a degree of specificity. As for cerebral and cerebellar heterotopias, they cannot be considered as real malformations as they are frequently found in premature newborns and disappear with maturation, thus proving that they are a sign of immaturity. There is still a lot of work to be done before we are able to meet the request for fetal integrity formulated by contemporary couples.

Bilateral cystic nephroblastomas and multiple malformations with trisomy 8 mosaicism

The case of a 16-month-old female infant with bilateral cystic nephroblastomas, Dandy-Walker syndrome, microcephaly, bilateral cataracts, and cerebellar heterotopia is reported. The patient's older sister, who had had bilateral cystic nephroblastomas, botryoid sarcoma involving the vagina and urinary bladder, microcephaly, arhinencephaly, and bilateral cataracts, was described in a previous report. Chromosomal study in the present case confirmed trisomy 8 mosaicism (rate of mosaicism, 16 per cent). The familial occurrence and the chromosomal disorder suggest a syndrome involving genetic abnormalities.

Brain abnormalities in infants with Potter syndrome (oligohydramnios tetrad)

We examined the brains of seven unrelated infants with Potter syndrome (oligohydramnios tetrad), a lethal neonatal disorder characterized by abnormal facies, lung hypoplasia, limb deformities, and classically, renal agenesis. All infants had defects of neuronal migration. The brains were small for gestational age in five of seven infants, and in four infants, the middle and inferior temporal gyri were incompletely demarcated. Cerebellar heterotopia occurred in five infants. All had abnormal hippocampi and abnormal lamination of the cerebral cortex. These neuropathologic abnormalities suggest that Potter syndrome may not be the result of a single toxic or infectious insult but may represent a polygenic inherited disorder.