Role of TOE1 variants at the nuclear localization motif in pontocerebellar hypoplasia 7

Biallelic TOE1 variants can cause pontocerebellar hypoplasia type 7 (PCH7), a condition characterized by pontocerebellar hypoplasia with genital abnormality. TOE1 is a 3'-exonuclese for 3'-end maturation in small nuclear RNA. TOE1 pathogenic variants have been reported at the DEDD catalytic domain and zinc finger motif. Here, we describe a PCH7 patient with novel compound heterozygous TOE1 variants and a detailed clinical course. The patient was a 3-year-old female and showed developmental delay without cerebellar ataxic behavior. Head MRI revealed delayed myelination without pontocerebellar hypoplasia at 9 months of age. Progressive pontocerebellar atrophy was prominent at follow-up MRI. Cerebral abnormalities are characteristic features of PCH7 before pontocerebellar atrophy is observed. One variant, p.Arg331*, was located at the nuclear localization motif (NLM) and partially escaped from nonsense-mediated decay. This variant affected nuclear localization in mutant expressing cells, thus, the TOE1 variant at NLM leads to TOE1 dysfunction associated with nuclear mis-localization.

Hydrocephalus associated with a molar tooth sign: A distinct subtype of Joubert syndrome

Hydrocephalus is rarely described in Joubert-Boltshauser syndrome (JBTS). The aim of this study was to investigate whether this association is a chance occurrence or potentially signifies a new phenotypic subtype. The databases of Wolfson Medical Center, Sourasky Medical Center, and EB's personal collection were reviewed. Records from an additional family were obtained from RG. The patients' medical records, prenatal ultrasounds, and magnetic resonance imaging were assessed. In addition, we reviewed the medical literature for the association of ventriculomegaly/hydrocephalus (VM/HC) in JBTS. Only seven cases (from five families) were found with prenatal onset of VM/HC, diagnosed during the second trimester; three pregnancies were terminated, one was stillborn and three were born, of which one died within a week, and another died at the age of 6 years. Additional central nervous system findings included dysgenesis of the corpus callosum, delayed sulcation, polymicrogyria, and pachygyria. We found 16 publications describing 54 patients with JBTS and VM/HC: only five were diagnosed at birth and three were diagnosed prenatally. Hydrocephalus is extremely rare in JBTS. The recurrence of this association, reported in several publications in multiple family members, suggests that it might represent a new phenotypic subtype of JBTS possibly associated with specific genes or variants. Further genetic studies are needed to confirm this hypothesis. WHAT THIS PAPER ADDS: The association of fetal hydrocephalus with Joubert-Boltshauser syndrome (JBTS) is very rare but not a chance association. This association represents a new phenotypic subtype of JBTS possibly linked to specific genes or variants.

I saw the "shrimp sign": Cerebellar progressive multifocal leukoencephalopathy

The shrimp sign is characterized by a well-defined lesion in the deep cerebellar white matter, with hyperintense signal on T2- and hypointense signal on T1-weighted imaging, abutting and outlining the dentate nucleus, unilaterally or bilaterally. This sign has high sensitivity and specificity for cerebellar progressive multifocal leukoencephalopathy (PML) within the correct clinical scenario. In this article, we present a case of cerebellar PML in a woman living with human immunodeficiency virus, who was not using antiretroviral therapy, and presented the shrimp sign on brain MRI.

Case of pediatric cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome in a 2-year-old girl

Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome is a recently described entity that refers to a specific pattern of cerebellar edema with restricted diffusion and crowding of the fourth ventricle among other findings. The syndrome is commonly associated with toxic opioid exposure. While most commonly seen in adults, we present a case of a 2-year-old girl who survived characteristic history and imaging findings of CHANTER syndrome.

The Frequency of Intermediate Alleles in Patients with Cerebellar Phenotypes

Cerebellar syndromes are clinically and etiologically heterogeneous and can be classified as hereditary, neurodegenerative non-hereditary, or acquired. Few data are available on the frequency of each form in the clinical setting. Growing interest is emerging regarding the genetic forms caused by triplet repeat expansions. Alleles with repeat expansion lower than the pathological threshold, termed intermediate alleles (IAs), have been found to be associated with disease manifestation. In order to assess the relevance of IAs as a cause of cerebellar syndromes, we enrolled 66 unrelated Italian ataxic patients and described the distribution of the different etiology of their syndromes and the frequency of IAs. Each patient underwent complete clinical, hematological, and neurophysiological assessments, neuroimaging evaluations, and genetic tests for autosomal dominant cerebellar ataxia (SCA) and fragile X-associated tremor/ataxia syndrome (FXTAS). We identified the following diagnostic categories: 28% sporadic adult-onset ataxia, 18% cerebellar variant of multiple system atrophy, 9% acquired forms, 9% genetic forms with full-range expansion, and 12% cases with intermediate-range expansion. The IAs were six in the FMR1 gene, two in the gene responsible for SCA8, and one in the ATXN2 gene. The clinical phenotype of patients carrying the IAs resembles, in most of the cases, the one associated with full-range expansion. Our study provides an exhaustive description of the causes of cerebellar ataxia, estimating for the first time the frequency of IAs in SCAs- and FXTAS-associated genes. The high percentage of cases with IAs supports further screening among patients with cerebellar syndromes.

Reduced cerebral blood flow and cognitive dysfunction following isolated cerebellar infarction: two case reports

Cognitive impairment in focal cerebellar disorders has been widely recognized and is described as cerebellar cognitive affective syndrome (CCAS). However, the relationship between CCAS and crossed cerebello-cerebral diaschisis (CCD) has rarely been discussed. The present report describes the uncommon phenomenon of CCD in two cases with isolated cerebellar infarction, and discuss its contribution to cognitive impairment. Cognitive performance was examined using the CCAS scale and a battery of neuropsychological assessments. Moreover, the relative distribution of cerebral and cerebellar blood flow was measured using three-dimensional arterial spin labeling imaging. Case 1 showed deficits in general cognition and had impaired language, episodic memory, and executive function. Case 2 showed deficits in general cognition at baseline, and cognitive deterioration of visuospatial abilities, language, episodic memory, and executive function was observed at the 3-month follow-up. Both cases met the diagnosis criteria of CCAS. Reduced cerebral blood flow was observed in the cerebral hemisphere contralateral to the cerebellar infarction at baseline in Case 1, and at the 3-month follow-up in Case 2. The present report describes cognitive decline after isolated cerebellar infarction in combination with contralateral cerebral hypoperfusion, as measured using quantitative arterial spin labeling. One possible mechanism involves the functional depression of cerebello-cerebral pathways.

Cerebellar leptomeningeal enhancement: An imaging finding of rapidly progressive Purkinje cell cytoplasmic autoantibody type 1 paraneoplastic cerebellar syndrome

Purkinje cell cytoplasmic autoantibody type 1 (PCA1), also known as anti-Yo, is a 'high-risk' paraneoplastic antibody, associated with rapidly progressive cerebellar syndrome. In patients with this syndrome, various MRI abnormalities have been documented, including atrophy in the cerebellum and brainstem, T2 hyperintensity in the brainstem and spinal cord, and cranial nerve enhancement. This report introduces an imaging finding, cerebellar leptomeningeal enhancement, which was observed in all three cases at early stages. Despite neurological deterioration, all patients underwent immunotherapy, and subsequent follow-up MRI revealed resolution of the leptomeningeal enhancement, suggesting that this feature is distinct from meningeal carcinomatosis.

Mixed Aphasia Caused by Bilateral Cerebellar Infarcts: a Case Report

Although neuroanatomical and physiological understanding of the cerebellum has evolved over recent decades and continues to develop, there is much that remains to be expounded upon, especially with regard to nonmotor roles. Neurocognitive and language processing is one area where involvement of the cerebellum is no longer in question, but the extent and mechanism of this relationship have yet to be defined. For example, which of the cerebellar hemispheres is involved continues to be debated. We present a case wherein a thrombus in the basilar artery led to bihemispheric cerebellar strokes with profound mixed effects on the patient's language and cognition. To the authors' knowledge, this is the first reported case of bilateral cerebellar strokes resulting in a mixed aphasia reported in scientific literature. This demonstrates the importance of continued research into a model for cerebellar function and the clinical impact of lesions to various cerebellar regions.

A missense variant in EXOSC8 causes exon skipping and expands the phenotypic spectrum of pontocerebellar hypoplasia type 1C

Pontocerebellar hypoplasia (PCH) is a rare heterogeneous neurodegenerative disorder affecting the pons and cerebellum and is currently classified into 17 types (PCH1-PCH17). PCH1 is distinguishable from other types by the association of spinal motor neuron dysfunction. Based on the underlying genetic etiology, PCH1 is further classified into 6 different subtypes (PCH1 A-F). Of them, PCH type 1C is caused by pathogenic variants in EXOSC8 gene and so far, only four families have been described in the literature. In this study, we report a new patient with PCH1 who proved by whole-exome sequencing to harbor a novel homozygous missense variant in the splice region of EXOSC8 gene (c.238 G > A; p.Val80Ile). Studying mRNA of the patient confirmed that this variant results in skipping of exon 5 of the gene and early protein truncation. Our patient presented with the main clinical findings of PCH type 1C including psychomotor retardation, spasticity, spinal muscle atrophy, and respiratory problems. However, unlike most of the reported cases, he did not develop hearing or visual impairment and displayed a longer survival. In addition, our patient had dysmorphic facies, nystagmus, congenital esotropia and contractures which were infrequently described in patients with EXOSC8. Diaphragmatic hernia, dilated lateral ventricles, hypoplastic temporal lobes, and thinning of the brain stem were additional new findings noted in our patient. This study presents the fifth family with this extremely rare type of PCH and expands the associated clinical and brain imaging findings.

Analysis of the Clinical Features and Imaging Findings of Pontocerebellar Hypoplasia Type 2D Caused by Mutations in SEPSECS Gene

Pontocerebellar hypoplasia type 2D (PCH2D) caused by SEPSECS gene mutations is very rare and only described in a few case reports. In this study, we analyzed the clinical features and imaging findings of these individuals, so as to provide references for the clinic. We reported a case of PCH2D caused by a new complex heterozygote mutation in SEPSECS gene, and reviewed the literatures to summarize the clinical features and imaging findings and compare the differences between early-onset patients (EOPs) and late-onset patients (LOPs). Of 23 PCH2D patients, 19 cases were early-onset and 4 cases were late-onset, with average ages of 4.1 ± 4.0 years and 21.8 ± 9.4 years, females were more prevalent (14/19). EOPs mainly distributed in Arab countries (10/14) and Finland (4/14), while LOPs in East Asia (3/3). EOPs develop severe initial symptoms at the average age of 4.1 ± 7.8 months or shortly after birth, while LOPs experienced mild developmental delay in infancy. Microcephaly (10/11), intellectual disability (10/11), decreased motor function (10/11), and spastic or dystonic quadriplegia (8/10) were the common clinical features of EOPs and LOPs. EOPs also presented with visual impairment (5/7), seizures (4/7), neonatal irritability/opisthotonus (3/7), tremors/myoclonus (3/7), dysmorphic features (3/7), and other symptoms. EOPs were characterized by cerebellar symptoms (4/4). Magnetic resonance imaging (MRI) revealed progressive cerebellar atrophy followed by less pronounced cerebral atrophy, and there was no pons atrophy in LOPs. Most patients of PCH2D were severe early-onset, and a few were late-onset with milder symptoms. EOPs and LOPs shared some common clinical features and MRI findings, but also had their own characteristics.

Differentiating Genetic Forms of Pontocerebellar Hypoplasia From Acquired Lesions Resembling Pontocerebellar Hypoplasia: Clinical, Neurodevelopmental, and Imaging Insight From 19 Extremely Premature Patients

It is well established that extreme prematurity can be associated with cerebellar lesions potentially affecting the neurologic prognosis. One of the commonly observed lesions in these cases is pontocerebellar hypoplasia resulting from prematurity, which can pose challenges in distinguishing it from genetically caused pontocerebellar hypoplasia. This confusion leads to unacceptable and prolonged diagnostic ambiguity for families as well as difficulties in genetic counseling. Therefore, it is crucial to identify the clinical and neuroradiologic features allowing to differentiate between acquired and genetic forms of pontocerebellar hypoplasia in order to guide clinical practices and improve patient care. In this regard, we report in the present manuscript the clinical, developmental, and radiologic characteristics of 19 very premature children (gestational age <28 weeks, now aged 3-14 years) with cerebellar lesions and discuss the causal mechanisms. Our findings support the notion that a combination of specific clinical and radiologic criteria is essential in distinguishing between acquired and genetic forms of pontocerebellar hypoplasia.

Cerebellar Abscess Induced by Cochlear Fistula due to Chronic Suppurative Otitis Media

Cochlear fistulas with cholesteatoma as the primary disease have been reported frequently in the relevant literature. However, there are no reports of cochlear fistula without cholesteatoma due to chronic suppurative otitis media with intracranial complications. We report a case of cochlear fistula due to chronic otitis media that was diagnosed after the onset of a cerebellar abscess. The patient was a 25-year-old man with severe autism. He was admitted to our hospital with otorrhea from his left ear, emesis, and impaired consciousness. Computed tomography (CT) of the head showed left suppurative otitis media, left cerebellar abscess, and brainstem compression due to hydrocephalus. Right extra-ventricular drainage and brain abscess drainage were urgently performed. The next day, foramen magnum decompression and abscess drainage with partial resection of the swollen cerebellum were performed for decompression purposes. He was subsequently treated with antimicrobial therapy, but magnetic resonance imaging of the head showed an increase in the size of the cerebellar abscess. Re-examination of the temporal bone CT scans revealed a bony defect in the left cochlear promontory angle. We assumed that the cochlear fistula was responsible for the otogenic brain abscess. Thus, the patient underwent surgical closure of the cochlear fistula. After the operation, the cerebellar abscess lesion gradually shrank, and his general condition stabilized. Cochlear fistula should be considered in the management of patients with inflammatory middle ear disease associated with otogenic intracranial complications in the middle ear.

Cerebellar infarction caused by vertebral artery dissection: A case report

RATIONALE

Vertebral artery dissection is an important cause of posterior circulation ischemic stroke in young and middle-aged people. We reported a young man with cerebellar infarction caused by dissection of the right vertebral artery.

PATIENT CONCERNS

A 34-year-old man presented with intermittent dizziness, blurred vision, nausea, and transient tinnitus 10 days before admission. All these symptoms were gradually aggravated and followed by vomiting and unfavorable movement of the right limbs. All these symptoms gradually aggravated.

DIAGNOSIS

Neurological examination on admission showed ataxia of the right limbs. Magnetic resonance imaging of the head revealed a right cerebellar infarction. High-resolution vessel wall magnetic resonance imaging showed dissection of the right vertebral artery. Whole-brain CT digital subtraction angiography revealed occlusion of the third segment (V3) of the right vertebral artery. This supports the diagnosis of vertebral artery dissection.

INTERVENTIONS

The patient received anticoagulant treatment with warfarin.

OUTCOMES

After 2 weeks of treatment, the patient showed remarkably alleviated dizziness and unfavorable movement of the right limbs. After 3 months of treatment, the modified Rankin Scale score was 0. MRI of the head revealed that the original right cerebellar focus was softened, and there were no newly formed infarct foci.

LESSONS

When young and middle-aged patients without atherosclerotic risk factors encounter sudden dizziness, tinnitus, and unfavorable limb movement, vertebral artery dissection may be considered. Careful inquiry into the medical history may help make a final diagnosis. Further high-resolution vessel wall magnetic resonance imaging is an effective means to find arterial dissection. Early diagnosis and treatment for vertebral artery dissection has a favorable prognosis.

A presurgical voxel-wise predictive model for cerebellar mutism syndrome in children with posterior fossa tumors

BACKGROUND

This study aimed to investigate cerebellar mutism syndrome (CMS)-related voxels and build a voxel-wise predictive model for CMS.

METHODS

From July 2013 to January 2022, 188 pediatric patients diagnosed with posterior fossa tumor were included in this study, including 38 from a prospective cohort recruited between 2020 and January 2022, and the remaining from a retrospective cohort recruited in July 2013-Aug 2020. The retrospective cohort was divided into the training and validation sets; the prospective cohort served as a prospective validation set. Voxel-based lesion symptoms were assessed to identify voxels related to CMS, and a predictive model was constructed and tested in the validation and prospective validation sets.

RESULTS

No significant differences were detected among these three data sets in CMS rate, gender, age, tumor size, tumor consistency, presence of hydrocephalus and paraventricular edema. Voxels related to CMS were mainly located in bilateral superior and inferior cerebellar peduncles and the superior part of the cerebellum. The areas under the curves for the model in the training, validation and prospective validation sets were 0.889, 0.784 and 0.791, respectively.

CONCLUSIONS

Superior and inferior cerebellar peduncles and the superior part of the cerebellum were related to CMS, especially the right side, and voxel-based lesion-symptom analysis could provide valuable predictive information before surgery.

Surgical corridors for congenital aural atresia with otogenic cerebellar abscess and lateral sinus thrombosis

The following is a case report of an adolescent with mental retardation who had congenital aural atresia with contralateral congenital facial palsy. She developed multiple intracranial complications (cerebellar abscess and lateral sinus thrombosis) due to cholesteatoma. We managed her in a multidisciplinary approach. This report discusses case management, emphasising the meticulous intraoperative steps taken in identifying the landmarks and precautions adopted to avoid postoperative facial palsy and other complications.

Comparison of Cerebellar Grey Matter Alterations in Bipolar and Cerebellar Patients: Evidence from Voxel-Based Analysis

The aim of this study was to compare the patterns of cerebellar alterations associated with bipolar disease with those induced by the presence of cerebellar neurodegenerative pathologies to clarify the potential cerebellar contribution to bipolar affective disturbance. Twenty-nine patients affected by bipolar disorder, 32 subjects affected by cerebellar neurodegenerative pathologies, and 37 age-matched healthy subjects underwent a 3T MRI protocol. A voxel-based morphometry analysis was used to show similarities and differences in cerebellar grey matter (GM) loss between the groups. We found a pattern of GM cerebellar alterations in both bipolar and cerebellar groups that involved the anterior and posterior cerebellar regions (p = 0.05). The direct comparison between bipolar and cerebellar patients demonstrated a significant difference in GM loss in cerebellar neurodegenerative patients in the bilateral anterior and posterior motor cerebellar regions, such as lobules I-IV, V, VI, VIIIa, VIIIb, IX, VIIb and vermis VI, while a pattern of overlapping GM loss was evident in right lobule V, right crus I and bilateral crus II. Our findings showed, for the first time, common and different alteration patterns of specific cerebellar lobules in bipolar and neurodegenerative cerebellar patients, which allowed us to hypothesize a cerebellar role in the cognitive and mood dysregulation symptoms that characterize bipolar disorder.