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![Clinical photographs showing dystonic posturing in VPS16 patient cohort. (A) (i) Patient 9 F demonstrating orofacial dystonia elicited during speech; (ii) Patient 11 S1 showing cervical dystonia; (iii) Patient 12 showing upper limb posturing; (iv) Patient 11 S1 showing hand posturing; (v) Patient 12 showing spontaneous striatal toe on the left; (vi) Patient 12 as an adult, standing, showing exaggerated lumbar lordosis; and (vii) Patient 12 as an adult, standing, showing involuntary plantar flexion/ tiptoe posture. (B) Selected MRI brain images for patients with VPS16 dystonia. Abnormalities indicated by white arrows. (i) Axial T2 image from Patient 7 M (aged 34 years, pre-DBS) shows hypointensity consistent with iron deposition in the globi pallidi; (ii) susceptibility-weighted images (SWIs) from Patient 7 M showing hypointensity in the midbrain nuclei (above) and dentate nucleus of the cerebellum (below); (iii) axial SWI from Patient 7 M showing hypointensity of the globi pallidi; (iv) axial T2 image from Patient 1 (aged 10 years) showing hypointensity of the globi pallidi; (v) subtle generalized atrophy in Patient 9 F, demonstrated in a coronal T2 image of the cerebrum (above) and a sagittal T1 image of the cerebellum (below); (vi) axial SWI from Patient 10, aged 32 years, showing hypointensity in the globi pallidi; (vii) enlarged axial T2 image from Patient 13 F, aged 55 years, showing relatively small, bright caudates, and putamina; and (viii) axial SWI image from Patient 3 P (aged 21 years) showing hypointensity of the midbrain nuclei. [Color figure can be viewed at www.annalsofneurology.org]](publication/343775557/figure/fig2/AS:1001074618032128@1615686196057/Clinical-photographs-showing-dystonic-posturing-in-VPS16-patient-cohort-A-i-Patient.png)
Clinical photographs showing dystonic posturing in VPS16 patient cohort. (A) (i) Patient 9 F demonstrating orofacial dystonia elicited during speech; (ii) Patient 11 S1 showing cervical dystonia; (iii) Patient 12 showing upper limb posturing; (iv) Patient 11 S1 showing hand posturing; (v) Patient 12 showing spontaneous striatal toe on the left; (vi) Patient 12 as an adult, standing, showing exaggerated lumbar lordosis; and (vii) Patient 12 as an adult, standing, showing involuntary plantar flexion/ tiptoe posture. (B) Selected MRI brain images for patients with VPS16 dystonia. Abnormalities indicated by white arrows. (i) Axial T2 image from Patient 7 M (aged 34 years, pre-DBS) shows hypointensity consistent with iron deposition in the globi pallidi; (ii) susceptibility-weighted images (SWIs) from Patient 7 M showing hypointensity in the midbrain nuclei (above) and dentate nucleus of the cerebellum (below); (iii) axial SWI from Patient 7 M showing hypointensity of the globi pallidi; (iv) axial T2 image from Patient 1 (aged 10 years) showing hypointensity of the globi pallidi; (v) subtle generalized atrophy in Patient 9 F, demonstrated in a coronal T2 image of the cerebrum (above) and a sagittal T1 image of the cerebellum (below); (vi) axial SWI from Patient 10, aged 32 years, showing hypointensity in the globi pallidi; (vii) enlarged axial T2 image from Patient 13 F, aged 55 years, showing relatively small, bright caudates, and putamina; and (viii) axial SWI image from Patient 3 P (aged 21 years) showing hypointensity of the midbrain nuclei. [Color figure can be viewed at www.annalsofneurology.org]
Source publication
Objectives
The majority of people with suspected genetic dystonia remain undiagnosed after maximal investigation, implying that a number of causative genes have not yet been recognised. We aimed to investigate this paucity of diagnoses.
Methods
We undertook weighted burden analysis of whole‐exome sequencing data from 138 individuals with unresolve...
Context in source publication
Context 1
... Mild generalized cerebral atrophy was also apparent in 4 individuals. Although not grossly abnormal, caudate nuclei and putamina appeared relatively small and bright on T2 (Fig 3B, see Supplementary Table S4). Some patients had a partial response to levodopa, trihexyphenidyl, and/or botulinum toxin type A injections. ...
Citations
... A focused reanalysis for specific genes was performed through gene discovery collaborations and clinical correlation efforts during 2020-2023. Cases with a novel diagnosis found through these efforts were published previously [13][14][15]. In addition, we performed a systematic reanalysis of GS data. ...
... 6 In total, the combination of focused reanalysis for specific genes and gene panel-based systematic reanalysis of GS data enabled a molecular diagnosis in 8 additional probands (7.2 %), increasing the total diagnostic yield to 18.9 % (Fig. 1). Focused reanalysis of specific genes identified as part of gene discovery and clinical correlation efforts during 2020-2023 yielded a genetic diagnosis in four patients (3.6 %) [variants in VPS16 (two probands), AOPEP and POLG (Table 1) [13][14][15]]. The VPS16 and AOPEP cases were identified through gene discovery efforts. ...
... An expansion in the pathogenic range in ATXN2 associated with Spinocerebellar ataxia 2 (MIM#183090) was found in patient 17027, a 66-year-old woman with predominantly craniocervical dystonia and a previous diagnosis of VPS16-associated dystonia (Dystonia 30, MIM#619291) [13]. In patient 17068, we detected a repeat expansion in the pathogenic range in the ATXN8OS gene associated with spinocerebellar ataxia 8 (SCA8) (MIM#608768). ...
Purpose: We investigated the contribution of genomic data reanalysis to the diagnostic yield of dystonia patients who remained undiagnosed after prior genome sequencing.
Methods: Probands with heterogeneous dystonia phenotypes who underwent initial genome sequencing (GS) analysis in 2019 were included in the reanalysis, which was performed through gene-specific discovery collaborations and systematic genomic data reanalysis.
Results: Initial GS analysis in 2019 (n = 111) identified a molecular diagnosis in 11.7 % (13/111) of cases. Reanalysis between 2020 and 2023 increased the diagnostic yield by 7.2 % (8/111); 3.6 % (4/111) through focused gene-specific clinical correlation collaborative efforts [VPS16 (two probands), AOPEP and POLG], and 3.6 % (4/111) by systematic reanalysis completed in 2023 [NUS1 (two probands) and DDX3X variants, and a microdeletion encompassing VPS16]. Seven of these patients had a high phenotype-based dystonia score ≥3. Notable unverified findings in four additional cases included suspicious variants of uncertain significance in FBXL4 and EIF2AK2, and potential phenotypic expansion associated with SLC2A1 and TREX1 variants.
Conclusion: GS data reanalysis increased the diagnostic yield from 11.7 % to 18.9 %, with potential extension up to 22.5 %. While optimal timing for diagnostic reanalysis remains to be determined, this study demonstrates that periodic re-interrogation of dystonia GS datasets can provide additional genetic diagnoses, which may have significant implications for patients and their families.
... Lower limb onset has also been recorded in several cases and appears to relate to a younger age (under 20) [43]. (f) VPS16 (PS16 core subunit of corvet and homotypic fusion and vacuole protein sorting (HOPS) complexes-participates in autophagy) VPS16 variations were discovered in the context of early-onset generalized dystonia accompanied by lysosomal dysfunction [47]. Nevertheless, VPS16 variations have recently been discovered among patients suffering from focal dystonia [48]. ...
A neurological condition called dystonia results in abnormal, uncontrollable postures or movements because of sporadic or continuous muscular spasms. Several varieties of dystonia can impact people of all ages, leading to severe impairment and a decreased standard of living. The discovery of genes causing variations of single or mixed dystonia has improved our understanding of the disease’s etiology. Genetic dystonias are linked to several genes, including pathogenic variations of VPS16, TOR1A, THAP1, GNAL, and ANO3. Diagnosis of dystonia is primarily based on clinical symptoms, which can be challenging due to overlapping symptoms with other neurological conditions, such as Parkinson’s disease. This review aims to summarize recent advances in the genetic origins and management of focal dystonia.
... 33 Additionally, a recent study suggested the role of the homotypic fusion and protein sorting complex-mediated endosomallysosomal pathways in the dystonia pathogenesis. 34 Therefore, it might be speculated that AOPEP could be implicated in the dystonia pathogenesis through being involved in the endosomallysosomal pathways ( figure 2A). ...
Background
Dystonia is one of the most common movement disorders. To date, the genetic causes of dystonia in populations of European descent have been extensively studied. However, other populations, particularly those from the Middle East, have not been adequately studied. The purpose of this study is to discover the genetic basis of dystonia in a clinically and genetically well-characterised dystonia cohort from Turkey, which harbours poorly studied populations.
Methods
Exome sequencing analysis was performed in 42 Turkish dystonia families. Using co-expression network (CEN) analysis, identified candidate genes were interrogated for the networks including known dystonia-associated genes and genes further associated with the protein-protein interaction, animal model-based characteristics and clinical findings.
Results
We identified potentially disease-causing variants in the established dystonia genes ( PRKRA, SGCE, KMT2B, SLC2A1, GCH1, THAP1, HPCA, TSPOAP1, AOPEP ; n=11 families (26%)), in the uncommon forms of dystonia-associated genes ( PCCB, CACNA1A, ALDH5A1, PRKN ; n=4 families (10%)) and in the candidate genes prioritised based on the pathogenicity of the variants and CEN-based analyses (n=11 families (21%)). The diagnostic yield was found to be 36%. Several pathways and gene ontologies implicated in immune system, transcription, metabolic pathways, endosomal-lysosomal and neurodevelopmental mechanisms were over-represented in our CEN analysis.
Conclusions
Here, using a structured approach, we have characterised a clinically and genetically well-defined dystonia cohort from Turkey, where dystonia has not been widely studied, and provided an uncovered genetic basis, which will facilitate diagnostic dystonia research.
... Autophagy -VPS16 (PS16 core subunit of corvet and HOPS complexes) VPS16 variations were discovered in the context of early-onset global dystonia accompanied by lysosomal dysfunction [44]. Nevertheless, VPS16 variations have recently been discovered among patients suffering from focal dystonia [45]. ...
... Report of the Guideline Development Subcommittee of the American Academy of Neurology[44]. (Created with BioRender.com). ...
Dystonia is a neurological disorder that results in atypical uncontrolled motions or postures caused by either continuous or intermittent contractions of the muscles. Subtypes of dystonia vary in their symptoms and severity; they can affect people of all ages and cause significant disability and poor quality of life. Identifying genes responsible for single or mixed dystonia variants has improved our understanding of its pathogenesis. The mechanisms underlying several of the most prevalent genetic dystonias, including idiopathic dystonia, TOR1A, THAP1, and KMT2B mutations, involve anomalies in transcriptional regulation, striatal dopaminergic signaling, synaptic plasticity, and a loss of inhibition at neuronal circuits. Dystonia is mostly diagnosed based on clinical indicators, and the diagnosis and etiology of this illness remain a problem. In this review, we tried to summarize novel updates about genetic causes and treatment of focal dystonia.
... INPP5E-associated Joubert syndrome, as discussed aboveand other conditions that perturb lysosomal trafficking. For mutations in Vps41 and other HOPS subunits, the main disease manifestations are neurological disorders often involving dystonia (Monfrini et al., 2021a,b;Sanderson et al., 2021;Steel et al., 2020;van der Welle et al., 2021). These HOPS mutations cause lysosomal abnormalities in fibroblasts (Monfrini et al., 2021a;Steel et al., 2020;van der Welle et al., 2021), but the mechanism linking those lysosomal defects to the dystonia phenotype is unclear. ...
... For mutations in Vps41 and other HOPS subunits, the main disease manifestations are neurological disorders often involving dystonia (Monfrini et al., 2021a,b;Sanderson et al., 2021;Steel et al., 2020;van der Welle et al., 2021). These HOPS mutations cause lysosomal abnormalities in fibroblasts (Monfrini et al., 2021a;Steel et al., 2020;van der Welle et al., 2021), but the mechanism linking those lysosomal defects to the dystonia phenotype is unclear. Investigating whether Rab19 is mislocalized and whether ciliogenesis is impaired by these HOPS mutations could inform potential treatments for HOPSassociated neurological disorders. ...
Primary cilia are sensory cellular organelles crucial for organ development and homeostasis. Ciliogenesis in polarized epithelial cells requires Rab19-mediated clearing of apical cortical actin to allow the cilium to grow from the apically docked basal body into the extracellular space. Loss of the lysosomal membrane-tethering homotypic fusion and protein sorting (HOPS) complex disrupts this actin clearing and ciliogenesis, but it remains unclear how the ciliary function of HOPS relates to its canonical function in regulating late endosome-lysosome fusion. Here, we show that disruption of HOPS-dependent lysosomal fusion indirectly impairs actin clearing and ciliogenesis by disrupting the targeting of Rab19 to the basal body, and that this effect is specific to polarized epithelial cells. We also find that Rab19 functions in endolysosomal cargo trafficking in addition to having its previously identified role in ciliogenesis. In summary, we show that inhibition of lysosomal fusion leads to the abnormal accumulation of Rab19 on late endosomes, thus depleting Rab19 from the basal body and thereby disrupting Rab19-mediated actin clearing and ciliogenesis in polarized epithelial cells.
... The VPS16 is known to be predominantly associated with late endosomes/lysosomes, and therefore, may mediate vesicle trafficking steps in the endosome/ lysosome pathway in diabetic retinas. Moreover, loss of function of VPS16 gene causes early onset dystonia associated with lysosomal abnormalities (26). Another example is PRXD1 present exclusively in diabetic retinas. ...
Introduction
As a metabolic disease, diabetes often leads to health complications such as heart failure, nephropathy, neurological disorders, and vision loss. Diabetic retinopathy (DR) affects as many as 100 million people worldwide. The mechanism of DR is complex and known to impact both neural and vascular components in the retina. While recent advances in the field have identified major cellular signaling contributing to DR pathogenesis, little has been reported on the protein post-translational modifications (PTM) - known to define protein localization, function, and activity - in the diabetic retina overall. Protein glycosylation is the enzymatic addition of carbohydrates to proteins, which can influence many protein attributes including folding, stability, function, and subcellular localization. O -linked glycosylation is the addition of sugars to an oxygen atom in amino acids with a free oxygen atom in their side chain (i.e., threonine, serine). To date, more than 100 congenital disorders of glycosylation have been described. However, no studies have identified the retinal O -linked glycoproteome in health or disease. With a critical need to expedite the discovery of PTMomics in diabetic retinas, we identified both global changes in protein levels and the retinal O -glycoproteome of control and diabetic mice.
Methods
We used liquid chromatography/mass spectrometry-based proteomics and high throughput screening to identify proteins differentially expressed and proteins differentially O -glycosylated in the retinas of wildtype and diabetic mice.
Results
Changes in both global expression levels of proteins and proteins differentially glycosylated in the retinas of wild-type and diabetic mice have been identified. We provide evidence that diabetes shifts both global expression levels and O -glycosylation of metabolic and synaptic proteins in the retina.
Discussion
Here we report changes in the retinal proteome of diabetic mice. We highlight alterations in global proteins involved in metabolic processes, maintaining cellular structure, trafficking, and neuronal processes. We then showed changes in O -linked glycosylation of individual proteins in the diabetic retina.
... Indeed, the use of omics technologies (e.g., genomics, transcriptomics, proteomics and metabolomics) has greatly contributed to optimize the clinical management of different LSDs patients [6], and can provide new insights into the mechanisms underlying these disorders [42,43]. In addition, these technologies have also allowed the discovery of new genes involved in LSDs [44,45], and the identification of biomarkers associated with specific health conditions [46][47][48][49]. Notably, since these disorders are characterized by the accumulation of specific metabolites, the characterization of the metabolic phenotype of these patients can be used to guide in the diagnosis, evaluation of disease severity, treatment decision and monitoring of LSD patients [50]. ...
Lysosomal storage disorders (LSDs) constitute a large group of rare, multisystemic, inherited disorders of metabolism, characterized by defects in lysosomal enzymes, accessory proteins, membrane transporters or trafficking proteins. Pompe disease (PD) is produced by mutations in the acid alpha-glucosidase (GAA) lysosomal enzyme. This enzymatic deficiency leads to the aberrant accumulation of glycogen in the lysosome. The onset of symptoms, including a variety of neurological and multiple-organ pathologies, can range from birth to adulthood, and disease severity can vary between individuals. Although very significant advances related to the development of new treatments, and also to the improvement of newborn screening programs and tools for a more accurate diagnosis and follow-up of patients, have occurred over recent years, there exists an unmet need for further understanding the molecular mechanisms underlying the progression of the disease. Also, the reason why currently available treatments lose effectiveness over time in some patients is not completely understood. In this scenario, characterization of the metabolic phenotype is a valuable approach to gain insights into the global impact of lysosomal dysfunction, and its potential correlation with clinical progression and response to therapies. These approaches represent a discovery tool for investigating disease-induced modifications in the complete metabolic profile, including large numbers of metabolites that are simultaneously analyzed, enabling the identification of novel potential biomarkers associated with these conditions. This review aims to highlight the most relevant findings of recently published omics-based studies with a particular focus on describing the clinical potential of the specific metabolic phenotypes associated to different subgroups of PD patients.
... D. Steel и соавт. (2020 г.) [1] сообщили о 19 пациентах из 14 неродственных семей европейского происхождения с DYT30. У пациентов в возрасте от 17 до 69 лет наблюдалась прогрессирующая дистония с ранним началом в среднем возрасте 12 лет (от 3 до 50). ...
A 58-year-old patient with type 30 dystonia (OMIM619291) detected by genome-wide sequencing was described. A variant of rs778751388, not previously described in the literature, has been identified in the heterozygous state in exon 2 of 24 of the VPS16 gene, leading to the amino acid substitution of P.Cys36A4rg. DNA change (HG38)(protein change) 20:g.2859771TC ENST00000380445.8:c.106TC ENSP00000369810.3:p.Cys36Arg. The patient's disease began quite late, in the 4th decade of life, with spastic torticollis. Subsequently, the spread of the pathological process involving the muscles of the neck, the right upper limb, then the right lower limb, myoclonia of the right hand and tremor of the right lower limb was noted. Secondary mitochondrial disorders were revealed in the form of an increase in the level of lactate in the blood before and after loading with carbohydrates. A decrease in the activity of mitochondrial enzymes in peripheral blood lymphocytes was also revealed: succinate dehydrogenase, an enzyme of the mitochondrial respiratory chain complex II; -glycerophosphate dehydrogenase involved in mitochondrial fat metabolism; glutamate dehydrogenase (amino acid metabolism in mitochondria). The level of lactate dehydrogenase in peripheral blood lymphocytes in the patient was elevated. The identified secondary mitochondrial disorders may be an indication for the appointment of energotropic medicines along with levodopa drugs and dopaminergic receptor agonists. In the presented observation, it can be argued about autosomal dominant inheritance, since the patient has a characteristic clinical picture of the disease and a mutation in the heterozygous state in the VPS16 gene was detected.
... The c.1370T>C (p.Leu457Pro) missense variant was identified in a male CD patient with retrocollis and dysarthria, and the c.241-2A>C splice site variant was found in a female with BSP. VPS16 variants were first described in the background of an early-onset generalized dystonic disorder with lysosomal dysfunction [21]. However, VPS16 variants have recently been detected in patients with focal dystonia [22]. ...
... With this technique, a mean on-target coverage of 290.9 was achieved, and 97.8% of the targets were covered at least 20×. For the annotation of variants, the ANNOVAR software tool was used (version 2.0.2, 17 July 2017) [21]. Variant interpretation was carried out in accordance with the 2015 guidelines of the American College of Medical Genetics and Genomics [28] using Franklin bioinformatic sites (https://franklin.genoox.com ...
... In the 14 cases in which WES was performed, copy number variation (CNV) analysis was also completed. Abbreviations: ANO3-anoctamin 3 [31]; ATM-ataxia-telangiectasia mutated [32]; ATP7B-ATPase copper transporting beta [33]; C19orf12-chromosome 19 open reading frame 12 [34]; CACNA1A-calcium channel, voltage-dependent, P/Q type, alpha-1A subunit [35]; CACNA1B-calcium channel, voltage-dependent, N type, alpha-1B subunit [36]; CIZ1-CIP1-interacting zinc finger protein [37]; COL6A3-collagen, type VI, alpha-3 [38]; CP-ceruloplasmin [39]; DRD5-dopamine receptor D5 [40]; FTL-ferritin light chain [41]; FUS-fused in sarcoma [15]; GCH1-GTP cyclohydrolase 1 [42]; GNAL-guanine nucleotide-binding protein alpha-activating activity polypeptide, olfactory type [20]; KMT2B-lysine-specific methyltransferase 2B [43]; LRRK2-leucinerich repeat kinase 2 [15]; PANK2-pantothenate kinase 2 [44]; PRKRA-protein kinase, interferon-inducible double-stranded RNA-dependent activator [17]; RAB12-RAS-associated protein RAB12 [45]; REEP4-receptor expression-enhancing protein 4 [16]; SGCE-sarcoglycan, epsilon [46]; SPR-sepiapterin reductase [47]; SYNE1spectrin repeat-containing nuclear envelope protein 1 [15]; TH-tyrosine hydroxylase [48]; THAP1-THAP domain-containing protein 1 [49]; TOR1A-torsin 1A [50]; TUBB4A-tubulin, beta-4A [51]; VPS16-VPS16 core subunit of corvet and HOPS complexes [52]; VPS41-VPS41 subunit of HOPS complex [21]; WDR45-WD repeat-containing protein 45 [53]. ...
Dystonia is a rare movement disorder which is characterized by sustained or intermittent muscle contractions causing abnormal and often repetitive movements, postures, or both. The two most common forms of adult-onset focal dystonia are cervical dystonia (CD) and benign essential blepharospasm (BSP). A total of 121 patients (CD, 74; BSP, 47) were included in the study. The average age of the patients was 64 years. For the next-generation sequencing (NGS) approach, 30 genes were selected on the basis of a thorough search of the scientific literature. Assessment of 30 CD- and BSP-associated genes from 121 patients revealed a total of 209 different heterozygous variants in 24 genes. Established clinical and genetic validity was determined for nine heterozygous variations (three likely pathogenic and six variants of uncertain significance). Detailed genetic examination is an important part of the work-up for focal dystonia forms. To our knowledge, our investigation is the first such study to be carried out in the Middle-European region.
... This difference in behavioral onset could indicate a neurodevelopmental period during which network dysfunction leads to dystonia, coinciding with a critical developmental window that also appears relevant to other neurodevelopmental disorders including autism spectrum disorders (14). In accordance with this hypothesis, a number of the recently identified dystonia-associated mutations involve genes that are also known for their role in neurodevelopment, including the autism-associated gene, CDH8 (15)(16)(17)(18)(19)(20). In addition, dystonia is also a frequent comorbidity in infants with other genetic, neurodevelopmental disorders including Rett syndrome (MECP2 mutations) (21,22), Partington syndrome (ARX mutations) (23), and as mentioned before, in an array of patients with autism spectrum disorders (24,25). ...
Converging evidence from structural imaging studies in patients, the function of dystonia-causing genes, and the comorbidity of neuronal and behavioral defects all suggest that pediatric-onset dystonia is a neurodevelopmental disorder. However, to fully appreciate the contribution of altered development to dystonia, a mechanistic understanding of how networks become dysfunctional is required for early-onset dystonia. One current hurdle is that many dystonia animal models are ideally suited for studying adult phenotypes, as the neurodevelopmental features can be subtle or are complicated by broad developmental deficits. Furthermore, most assays that are used to measure dystonia are not suited for developing postnatal mice. Here, we characterize the early-onset dystonia in Ptf1a Cre ;Vglut2 fl/fl mice, which is caused by the absence of neurotransmission from inferior olive neurons onto cerebellar Purkinje cells. We investigate motor control with two paradigms that examine how altered neural function impacts key neurodevelopmental milestones seen in postnatal pups (postnatal day 7–11). We find that Ptf1a Cre ;Vglut2 fl/fl mice have poor performance on the negative geotaxis assay and the surface righting reflex. Interestingly, we also find that Ptf1a Cre ;Vglut2 fl/fl mice make fewer ultrasonic calls when socially isolated from their nests. Ultrasonic calls are often impaired in rodent models of autism spectrum disorders, a condition that can be comorbid with dystonia. Together, we show that these assays can serve as useful quantitative tools for investigating how neural dysfunction during development influences neonatal behaviors in a dystonia mouse model. Our data implicate a shared cerebellar circuit mechanism underlying dystonia-related motor signs and social impairments in mice.
