Clinical and molecular genetic assessment of a chorea-acanthocytosis pedigree

VPS13A knockdown impairs corticostriatal synaptic plasticity and locomotor behavior in a new mouse model of chorea-acanthocytosis

Chorea-acanthocytosis (ChAc) is an inherited neurodegenerative movement disorder caused by VPS13A gene mutations leading to the absence of protein expression. The striatum is the most affected brain region in ChAc patients. However, the study of the VPS13A function in the brain has been poorly addressed. Here we generated a VPS13A knockdown (KD) model and aimed to elucidate the contribution of VPS13A to synaptic plasticity and neuronal communication in the corticostriatal circuit. First, we infected primary cortical neurons with miR30-shRNA against VPS13A and analyzed its effects on neuronal plasticity. VPS13A-KD neurons showed a higher degree of branching than controls, accompanied by decreased BDNF and PSD-95 levels, indicative of synaptic alterations. We then injected AAV-KD bilaterally in the frontal cortex and two different regions of the striatum of mice and analyzed the effects of VPS13A-KD on animal behavior and synaptic plasticity. VPS13A-KD mice showed modification of the locomotor behavior pattern, with increased exploratory behavior and hyperlocomotion. Corticostriatal dysfunction in VPS13A-KD mice was evidenced by impaired striatal long-term depression (LTD) after stimulation of cortical afferents, which was partially recovered by BDNF administration. VPS13A-KD did not lead to neuronal loss in the cortex or the striatum but induced a decrease in the neuronal release of CX3CL1 and triggered a microglial reaction, especially in the striatum. Notably, CX3CL1 administration partially restored the impaired corticostriatal LTD in VPS13A-KD mice. Our results unveil the involvement of VPS13A in neuronal connectivity modifying BDNF and CX3CL1 release. Moreover, the involvement of VPS13A in synaptic plasticity and motor behavior provides key information to further understand not only ChAc pathophysiology but also other neurological disorders.

Movement disorders of the mouth: a review of the common phenomenologies

Movement disorders of the mouth encompass a spectrum of hyperactive movements involving the muscles of the orofacial complex. They are rare conditions and are described in the literature primarily in case reports originating from neurologists, psychiatrists, and the dental community. The focus of this review is to provide a phenomenological description of different oral motor disorders including oromandibular dystonia, orofacial dyskinesia and orolingual tremor, and to offer management strategies for optimal treatment based on the current literature. A literature search of full text studies using PubMed/Medline and Cochrane library combined with a manual search of the reference lists was conducted until June 2021. Results from this search included meta-analyses, systematic reviews, reviews, clinical studies, case series, and case reports published by neurologists, psychiatrists, dentists and oral and maxillofacial surgeons. Data garnered from these sources were used to provide an overview of most commonly encountered movement disorders of the mouth, aiding physicians in recognizing these rare conditions and in initiating appropriate therapy.

Unraveling the Spatiotemporal Distribution of VPS13A in the Mouse Brain

Loss-of-function mutations in the human vacuolar protein sorting the 13 homolog A (VPS13A) gene cause Chorea-acanthocytosis (ChAc), with selective degeneration of the striatum as the main neuropathologic feature. Very little is known about the VPS13A expression in the brain. The main objective of this work was to assess, for the first time, the spatiotemporal distribution of VPS13A in the mouse brain. We found VPS13A expression present in neurons already in the embryonic stage, with stable levels until adulthood. VPS13A mRNA and protein distributions were similar in the adult mouse brain. We found a widespread VPS13A distribution, with the strongest expression profiles in the pons, hippocampus, and cerebellum. Interestingly, expression was weak in the basal ganglia. VPS13A staining was positive in glutamatergic, GABAergic, and cholinergic neurons, but rarely in glial cells. At the cellular level, VPS13A was mainly located in the soma and neurites, co-localizing with both the endoplasmic reticulum and mitochondria. However, it was not enriched in dendritic spines or the synaptosomal fraction of cortical neurons. In vivo pharmacological modulation of the glutamatergic, dopaminergic or cholinergic systems did not modulate VPS13A concentration in the hippocampus, cerebral cortex, or striatum. These results indicate that VPS13A has remarkable stability in neuronal cells. Understanding the distinct expression pattern of VPS13A can provide relevant information to unravel pathophysiological hallmarks of ChAc.

Chorea-acanthocytosis: A Case Report with Review of Oral Manifestations

Chorea-acanthocytosis (ChAc) is an autosomal recessive, progressive neurological disorder due to mutation in VPS13A gene causing defects in sorting of protein making the cell membrane unstable, leading to star-shaped erythrocytes. This neurological disorder includes features such as elevated creatinine kinase, atrophy of basal ganglia, and oral manifestations such as frequent cheek and tongue biting. It is a rare neurological condition with an estimate of <1000 cases worldwide. A case of 47-year-old male patient with a history of seizures and neurological problems presenting with oral ulceration has been discussed. The diagnosis of ChAc was confirmed by molecular investigations showing VPS13A gene mutation. The physical appearance includes chorea and dystonia with impaired gait. We attempt to highlight the oral features of ChAc. The oral manifestations include frequent tongue and cheek biting occurring due to dystonia affecting the muscles of head and neck region.

Novel pathogenic VPS13A mutation in Moroccan family with Choreoacanthocytosis: a case report

Background

Choreoacanthocytosis (ChAc), is a rare neurodegenerative disease, characterized by movement disorders and acanthocytosis in the peripheral blood smears, and various neurological, neuropsychiatric and neuromuscular signs. It is caused by mutations in VPS13A gene with autosomal recessive pattern of inheritance.

Case presentation

Here we report two patients belonging to a consanguineous Moroccan family who present with movement disorder pathology. They were suspected to have choreoacanthocytosis according to biological, clinical and radiological finding. Thus, whole-exome sequencing was performed for precise diagnosis and identified a homozygous novel nonsense mutation c.337C > T (p.Gln113*) in exon 5 of VPS13A in the two affected siblings.

Conclusion

Here, we report a novel nonsense p.Gln113* mutation in VPS13A identified by whole-exome sequencing, which caused ChAc in a Moroccan family. This is the first description of ChAc in Morocco with genetic confirmation, that expands the mutation diversity of VPS13A and provide clinical, neuroimaging and deep brain stimulation findings.

Novel pathogenic VPS13A gene mutations in Japanese patients with chorea-acanthocytosis

Objective

To identify mutations in vacuolar protein sorting 13A (VPS13A) for Japanese patients with suspected chorea-acanthocytosis (ChAc).

Methods

We performed a comprehensive mutation screen, including sequencing and copy number variation (CNV) analysis of the VPS13A gene, and chorein Western blotting of erythrocyte ghosts. As the results of the analysis, 17 patients were molecularly diagnosed with ChAc. In addition, we investigated the distribution of VPS13A gene mutations and clinical symptoms in a total of 39 molecularly diagnosed Japanese patients with ChAc, including 22 previously reported cases.

Results

We identified 11 novel pathogenic mutations, including 1 novel CNV. Excluding 5 patients with the unknown symptoms, 97.1% of patients displayed various neuropsychiatric symptoms or forms of cognitive dysfunction during the course of disease. The patients carrying the 2 major mutations representing over half of the mutations, exon 60–61 deletion and exon 37 c.4411C>T (R1471X), were localized in western Japan.

Conclusions

We identified 13 different mutations in VPS13A, including 11 novel mutations, and verified the clinical manifestations in 39 Japanese patients with ChAc.

Novel pathogenic XK mutations in McLeod syndrome and interaction between XK protein and chorein

Objective

To identify XK pathologic mutations in 6 patients with suspected McLeod syndrome (MLS) and a possible interaction between the chorea-acanthocytosis (ChAc)- and MLS-responsible proteins: chorein and XK protein.

Methods

Erythrocyte membrane proteins from patients with suspected MLS and patients with ChAc, ChAc mutant carriers, and normal controls were analyzed by XK and chorein immunoblotting. We performed mutation analysis and XK immunoblotting to molecularly diagnose the patients with suspected MLS. Lysates of cultured cells were co-immunoprecipitated with anti-XK and anti-chorein antibodies.

Results

All suspected MLS cases were molecularly diagnosed with MLS, and novel mutations were identified. The average onset age was 46.8 ± 8 years, which was older than that of the patients with ChAc. The immunoblot analysis revealed remarkably reduced chorein immunoreactivity in all patients with MLS. The immunoprecipitation analysis indicated a direct or indirect chorein-XK interaction.

Conclusions

In this study, XK pathogenic mutations were identified in all 6 MLS cases, including novel mutations. Chorein immunoreactions were significantly reduced in MLS erythrocyte membranes. In addition, we demonstrated a possible interaction between the chorein and XK protein via molecular analysis. The reduction in chorein expression is similar to that between Kell antigens and XK protein, although the chorein-XK interaction is a possibly noncovalent binding unlike the covalent Kell-XK complex. Our results suggest that reduced chorein levels following lack of XK protein are possibly associated with molecular pathogenesis in MLS.

Hereditary chorea - what else to consider when the Huntington's disease genetics test is negative?

Chorea, cognitive, behavioural and psychiatric disturbance occur in varying combinations in Huntington's disease (HD). This is often easy to recognise particularly in the presence of an autosomal dominant history. Whilst HD may be the most common aetiology of such a presentation, several HD phenocopies should be considered if genetic testing for HD is negative. We searched PubMed and the Cochrane Database from January 1, 1946 up to January 1, 2016, combining the search terms: 'chorea', 'Huntington's disease', 'HDL' and 'phenocopies'. HD phenocopies frequently display additional movement disorders such as myoclonus, dystonia, parkinsonism and tics. Here, we discuss the phenotypes, and investigations of HD-like disorders where the combination of progressive chorea and cognitive impairment is obvious, but HD gene test result is negative. Conditions presenting with sudden onset chorea such as vascular, infectious and autoimmune causes are not the primary focus of our discussion, but we will make a passing reference to these as some of these conditions are potentially treatable. Hereditary forms of chorea are a heterogeneous group of conditions and this number is increasing. While most of these conditions are not curable, molecular genetic testing has enabled many of these disorders to be distinguished from HD. Getting a precise diagnosis may enable patients and their families to better understand the nature of their condition.

Facial cellulitis revealing choreo-acanthocytosis: a case report

We report a 62 year-old-man with facial cellulitis revealing choreo-acanthocytosis (ChAc). He showed chorea that started 20 years ago. The orofacial dyskinisia with tongue and cheek biting resulted in facial cellulitis. The peripheral blood smear revealed acanthocytosis of 25%. The overall of chorea, orofacial dyskinetic disorder, peripheral neuropathy, disturbed behavior, acanthocytosis and the atrophy of caudate nuclei was suggestive of a diagnosis of ChAc. To our knowledge no similar cases of facial cellulitis revealing choreo-acanthocytosis (ChAc) were found in a review of the literature.

Chorein, the protein responsible for chorea-acanthocytosis, interacts with β-adducin and β-actin

Chorea-acanthocytosis (ChAc) is an autosomal, recessive hereditary disease characterized by striatal neurodegeneration and acanthocytosis, and caused by loss of function mutations in the vacuolar protein sorting 13 homolog A (VPS13A) gene. VPS13A encodes chorein whose physiological function at the molecular level is poorly understood. In this study, we show that chorein interacts with β-adducin and β-actin. We first compare protein expression in human erythrocyte membranes using proteomic analysis. Protein levels of β-adducin isoform 1 and β-actin are markedly decreased in erythrocyte membranes from a ChAc patient. Subsequent co-immunoprecipitation (co-IP) and reverse co-IP assays using extracts from chorein-overexpressing human embryonic kidney 293 (HEK293) cells, shows that β-adducin (isoforms 1 and 2) and β-actin interact with chorein. Immunocytochemical analysis using chorein-overexpressing HEK293 cells demonstrates co-localization of chorein with β-adducin and β-actin. In addition, immunoreactivity of β-adducin isoform 1 is significantly decreased in the striatum of gene-targeted ChAc-model mice. Adducin and actin are membrane cytoskeletal proteins, involved in synaptic function. Expression of β-adducin is restricted to the brain and hematopoietic tissues, corresponding to the main pathological lesions of ChAc, and thereby implicating β-adducin and β-actin in ChAc pathogenesis.

Different clinical phenotypes in siblings with a presenilin-1 P264L mutation

BACKGROUND

Mutations in the presenilin-1 gene (PSEN1) have been identified in autosomal dominant early-onset cases of Alzheimer's disease (AD).

AIMS

To investigate different clinical phenotypes of siblings possessing the same heterozygous P264L mutation in the PSEN1 gene.

METHODS

We evaluated clinical features, neuroimaging results, and neuropsychological examinations. The PSEN1 gene and other dementia-related gene mutations were screened.

RESULTS

We clinically diagnosed the proband as atypical AD with frontotemporal dementia features and diagnosed the elder brother of the proband as typical AD, based on neuropsychological symptoms and a brain imaging examination including amyloid imaging data. A heterozygous P264L mutation in the PSEN1 gene was identified in both siblings.

CONCLUSION

This study is one of few reports of AD siblings possessing the same mutation but exhibiting different clinical phenotypes in a Japanese family possessing a P264L mutation in the PSEN1 gene. The current results suggest that unknown modifiers, including both genetic and epigenetic factors, may alter the pathological and clinical phenotypes of a genetically predetermined disease.

Heteroplasmic m.1624C>T mutation of the mitochondrial tRNA(Val) gene in a proband and his mother with repeated consciousness disturbances

Homoplasmic m.1624C>T mutation of the mitochondrial tRNA(Val) gene was previously demonstrated to cause fatal neonatal Leigh syndrome. Here, we report the clinical phenotypes of a Japanese male and his mother with heteroplasmic m.1624C>T mutation. The 36-year-old male presented with repeated episodes of consciousness disturbance since the age of 25, cognitive decline, and personality change. Cerebrospinal fluid levels of lactate and pyruvate were elevated. His mother showed similar symptoms and course. The mutation m.1624C>T was identified heteroplasmically in the proband's muscle and leukocytes and in the mother's leukocytes. The heteroplasmy load decreased with age.

Subcellular localization and putative role of VPS13A/chorein in dopaminergic neuronal cells

Chorea-acanthocytosis (ChAc) is a rare hereditary neurodegenerative disorder caused by loss of function mutations in the vacuolar protein sorting 13 homolog A (VPS13A) gene encoding chorein. Although a deficiency in chorein function leads to apoptosis of striatal neurons in ChAc model mouse, its detailed subcellular localization and physiological role remain unclear. In this study, we produced two anti-chorein polyclonal antibodies and examined the intracellular localization of endogenous chorein in neuronal cells. Immunocytochemically, chorein was observed in the termini of extended neurites and partially colocalized with synaptotagmin I in differentiated PC12 cells. Subcellular localization analysis by sucrose density gradient fractionation showed that chorein and synaptotagmin I were located in dense-core vesicles (DCVs), which contain dopamine. In addition, PC12 cells stably expressing carboxyterminal fragment of chorein increased K(+)-induced dopamine release. Taken together, these results suggest that chorein is involved in exocytosis of DCV.

Familial semantic dementia with P301L mutation in the Tau gene

BACKGROUND/AIMS

Semantic dementia (SD) is a clinical subclassification of frontotemporal lobar degeneration. Patients with 'pure SD' present with semantic memory impairment preceding the frontal symptoms, and there have been no reports of familial cases.

METHODS

We evaluated the clinical features of, and performed neuropsychological examinations on, the proband and two affected family members. Then we performed neuroimaging and genetic analysis of MAPT and other dementia-related genes in the proband.

RESULTS

All three cases had semantic memory impairment with loss of word meanings as the primary early symptom. We diagnosed all cases as pure SD and identified a P301L mutation in the MAPT gene of the proband.

CONCLUSION

Although the P301L mutation identified here has been previously described as pathogenic for frontotemporal dementia with parkinsonism-17 (FTDP-17), the proband and his two affected relatives showed different clinical symptoms from those of typical FTDP-17 cases who carry the P301L mutation. Pathologically, pure SD usually shows a TAR DNA-binding protein proteinopathy, but the molecular understanding of SD is not well established. Although our cases were clinically pure SD, the proband has a tau gene mutation, which would lead to tauopathy. These findings suggest that reconsideration of the molecular understanding of SD is warranted.

Novel pathogenic mutations and copy number variations in the VPS13A gene in patients with chorea-acanthocytosis

Chorea-acanthocytosis (ChAc) is a rare autosomal recessive neurodegenerative disorder caused by loss of function mutations in the vacuolar protein sorting 13 homolog A (VPS13A) gene that encodes chorein. It is characterized by adult-onset chorea, peripheral acanthocytes, and neuropsychiatric symptoms. In the present study, we performed a comprehensive mutation screen, including sequencing and copy number variation (CNV) analysis, of the VPS13A gene in ChAc patients. All 73 exons and flanking regions of VPS13A were sequenced in 35 patients diagnosed with ChAc. To detect CNVs, we also performed real-time quantitative PCR and long-range PCR analyses for the VPS13A gene on patients in whom only a single heterozygous mutation was detected. We identified 36 pathogenic mutations, 20 of which were previously unreported, including two novel CNVs. In addition, we investigated the expression of chorein in 16 patients by Western blotting of erythrocyte ghosts. This demonstrated the complete absence of chorein in patients with pathogenic mutations. This comprehensive screen provides an accurate and useful method for the molecular diagnosis of ChAc.

Neuroacanthocytosis

The term "neuroacanthocytosis" describes a heterogeneous group of molecularly-defined disorders which result in progressive neurodegeneration, predominantly of the basal ganglia, and erythrocyte acanthocytosis. The clinical presentation of neuroacanthocytosis syndromes typically involves chorea and dystonia, but a range of other movement disorders may be seen. Psychiatric and cognitive symptoms may be prominent. There can be considerable phenotypic overlap; however, features of inheritance, age of onset, neuroimaging and laboratory findings, in addition to the spectrum of central and peripheral neurological abnormalities and extraneuronal involvement, can help to distinguish the specific syndromes. The two core neuroacanthocytosis syndromes, in which acanthocytosis is a typical, although not invariable finding, are autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome. Acanthocytes are found in a smaller proportion of patients with Huntington's disease-like 2 and pantothenate kinase-associated neurodegeneration. Additionally, acanthocytosis has been reported in a few patients with other neurological disorders. The causative genes do not appear to be linked by a specific function or pathway, although abnormalities of membrane processing may be implicated. The connection between the erythrocyte membrane abnormality, which results in the characteristic "thorny" protrusions, the vulnerability of the basal ganglia, and the respective genetic mutations, is obscure.

Comprehensive analysis of the genes responsible for neuroacanthocytosis in mood disorder and schizophrenia

Neuroacanthocytosis syndromes are mainly comprised of two diseases: chorea-acanthocytosis (ChAc) and McLeod syndrome (MLS). There is a high incidence of psychiatric disorders such as mood disorder and schizophrenia among neuroacanthocytosis patients. We hypothesized that neuroacanthocytosis-related-genes might be associated with susceptibility to these psychiatric disorders. We performed a comprehensive mutation screen of VPS13A and XK, the gene responsible for ChAc and MLS, respectively, in 85 mood disorder subjects and XK in 86 schizophrenia subjects and compared the variants to 100 or more control alleles. We also performed copy number variation (CNV) analysis in 72 mood disorder subjects and 86 schizophrenia subjects. We identified three non-synonymous, two synonymous and six intron variants in mood disorder subjects and a novel GAT triplet repeat polymorphism in VPS13A. By CNV analysis, we identified a heterozygous exon 60-61 deletion in VPS13A in one mood disorder subject. We identified one non-synonymous and one intron variant in mood disorder and schizophrenia subjects, respectively, in XK. The presence of a pathogenic mutation or a potentially functional variant in mood disorder or schizophrenia subjects suggests that neuroacanthocytosis-related-genes might be involved in the pathogenesis of these psychiatric disorders.