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© 2022 European Academy of Neurology, Background and purpose: Rare diseases affect up to 29 million people in the European Union, and almost 50% of them affect the nervous system or muscles. Delays in diagnosis and treatment onset and insufficient treatment choices are common. Clinical practice guidelines (CPGs) may improve the diagnosis and treatment of patients and optimize care pathways, delivering the best scientific evidence to all clinicians treating these patients. Recommendations are set for developing and reporting high-quality CPGs on rare neurological diseases (RNDs) within the European Academy of Neurology (EAN), through a consensus procedure. Methods: A group of 27 experts generated an initial list of items that were evaluated through a two-step Delphi consensus procedure and a face-to-face meeting. The final list of items was reviewed by an external review group of 58 members. Results: The consensus procedure yielded 63 final items. Items are listed according to the domains of the AGREE instruments and concern scope and purpose, stakeholder involvement, rigour of development, and applicability. Additional items consider reporting and ethical issues. Recommendations are supported by practical examples derived from published guidelines and are presented in two tables: (1) items specific to RND CPGs, and general guideline items of special importance for RNDs, or often neglected; (2) items for guideline development within the EAN. Conclusions: This guidance aims to provide solutions to the issues specific to RNDs. This consensus document, produced by many experts in various fields, is considered to serve as a starting point for further harmonization and for increasing the quality of CPGs in the field of RNDs.

© 2021 International Parkinson and Movement Disorder Society, Background: Huntington's disease (HD) is a rare neurodegenerative disorder with protean clinical manifestations. Its management is challenging, consisting mainly of off-label treatments. Objectives: The International Parkinson and Movement Disorder Society commissioned a task force to review and evaluate the evidence of available therapies for HD gene expansion carriers. Methods: We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Eligible randomized controlled trials were identified via an electronic search of the CENTRAL, MEDLINE, and EMBASE databases. All eligible trials that evaluated one or more of 33 predetermined clinical questions were included. Risk of bias was evaluated using the Cochrane Risk of Bias tool. A framework was adapted to allow for efficacy and safety conclusions to be drawn from the balance between the GRADE level of evidence and the importance of the benefit/harm of the intervention. Results: Twenty-two eligible studies involving 17 interventions were included, providing data to address 8 clinical questions. These data supported a likely effect of deutetrabenazine on motor impairment, chorea, and dystonia and of tetrabenazine on chorea. The data did not support a disease-modifying effect for premanifest and manifest HD. There was no eligible evidence to support the use of specific treatments for depression, psychosis, irritability, apathy, or suicidality. Similarly, no evidence was eligible to support the use of physiotherapy, occupational therapy, exercise, dietary, or surgical treatments. Conclusions: Data for therapeutic interventions in HD are limited and support only the use of VMAT2 inhibitors for specific motor symptoms.

Background: Chorea may be present in a number of diseases including hereditary disorders. Major advances have occurred in our understanding of the genetic background of those disorders, and the present short review aims at highlighting the most salient ones. Summary: Chorea is one of the major manifestations of Huntington’s disease. However, there are a number of other diseases, in which chorea is present as well and their list is in constant increase thanks to the availability of advanced molecular genetic diagnostic techniques. Finding of new genes followed by the investigation of further cases with part of the phenotype first described often leads to the recognition of additional aspects of the disorders, thus widening the scope of investigation and management. Likewise, assessment of genetic variations associated with specific aspects of the phenotype, in a way similar to approaches established in nongenetic disorders, has improved our understanding of phenotype variation. Knowledge on genetic background of chorea has ameliorated our diagnostic approaches. Furthermore, it opens new therapeutic strategies aimed at modifying expression both of the genes primarily implicated as the ones involved in further phenotype modification. Key messages: Recent research on the genetic background of disorders with chorea has provided data, which can now better guide differential diagnostic investigations in practical ways. Furthermore, they provide avenues for research on the disease mechanisms opening the door for clinical therapeutic trials.

[This corrects the article DOI: 10.3389/fneur.2022.817753.].

One percent of patients with a Huntington's disease (HD) phenotype do not have the Huntington (HTT) gene mutation. These are known as HD phenocopies. Their diagnosis is still a challenge. Our objective is to provide a diagnostic approach to HD phenocopies based on medical expertise and a review of the literature. We employed two complementary approaches sequentially: a review of the literature and two surveys analyzing the daily clinical practice of physicians who are experts in movement disorders. The review of the literature was conducted from 1993 to 2020, by extracting articles about chorea or HD-like disorders from the database Pubmed, yielding 51 articles, and analyzing 20 articles in depth to establish the surveys. Twenty-eight physicians responded to the first survey exploring the red flags suggestive of specific disease entities. Thirty-three physicians completed the second survey which asked for the classification of paraclinical tests according to their diagnostic significance. The analysis of the results of the second survey used four different clustering algorithms and the density-based clustering algorithm DBSCAN to classify the paraclinical tests into 1st, 2nd, and 3rd-line recommendations. In addition, we included suggestions from members of the European Reference Network-Rare Neurological Diseases (ERN-RND Chorea & Huntington disease group). Finally, we propose guidance that integrate the detection of clinical red flags with a classification of paraclinical testing options to improve the diagnosis of HD phenocopies.

Objective: Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder. Neurofilament light protein (NfL) is correlated with clinical severity of HD but relative data are the lack in the Chinese population. Reactive astrocytes are related to HD pathology, which predicts their potential to be a biomarker in HD progression. Our aim was to discuss the role of blood glial fibrillary acidic protein (GFAP) to evaluate clinical severity in patients with HD.Methods: Fifty-seven HD mutation carriers (15 premanifest HD, preHD, and 42 manifest HD) and 26 healthy controls were recruited. Demographic data and clinical severity assessed with the internationally Unified Huntington's Disease Rating Scale (UHDRS) were retrospectively analyzed. Plasma NfL and GFAP were quantified with an ultra-sensitive single-molecule (Simoa, Norcross, GA, USA) technology. We explored their consistency and their correlation with clinical severity.Results: Compared with healthy controls, plasma NfL (p < 0.0001) and GFAP (p < 0.001) were increased in Chinese HD mutation carriers, and they were linearly correlated with each other (r = 0.612, p < 0.001). They were also significantly correlated with disease burden, Total Motor Score (TMS) and Total Functional Capacity (TFC). The scores of Stroop word reading, symbol digit modalities tests, and short version of the Problem Behaviors Assessments (PBAs) for HD were correlated with plasma NfL but not GFAP. Compared with healthy controls, plasma NfL has been increased since stage 1 but plasma GFAP began to increase statistically in stage 2.Conclusions: Plasma GFAP was correlated with plasma NfL, disease burden, TMS, and TFC in HD mutation carriers. Plasma GFAP may have potential to be a sensitive biomarker for evaluating HD progression.

Limitation of functional ability is a major feature of Huntington's disease (HD). The International Parkinson and Movement Disorder Society (MDS) commissioned the appraisal of the use and clinimetric properties of clinical measures of functional ability that have been applied in HD studies and trials to date, to make recommendations regarding their use based on standardized criteria. After a systematic literature search, we included a total of 29 clinical measures grouped into two categories: (1) performance-based measures (e.g., balance, walking, and reaching/grasping), and (2) rating scales. Three performance-based measures are rated as "recommended": the Tinetti Mobility Test for screening of fall risk and for severity assessment of mobility in patients with manifest HD (up to stage III); the Berg Balance Scale for severity of balance impairment; and the Six-Minute Walk Test for assessment of walking endurance (severity) in HD subjects with preserved ambulation. No rating scale targeting functional ability reached a "recommended" status either for screening or severity measurement. The main challenges identified in this review include applying widely accepted conceptual frameworks to the identified measures, the lack of validation of clinical measures to detect change over time, and absence of validated measures for upper limb function. Furthermore, measures of capacity or ability to perform activities of daily living had ceiling effects in people with early and pre-manifest HD. We recommend that the MDS prioritize the development of new scales that capture small, but meaningful changes in function over time for outcome assessment in clinical trials, particularly in earlier stages of HD.

Background The clinical assessment of motor symptoms in Huntington's disease is usually performed with the Unified Huntington's Disease Rating Scale-Total Motor Score (UHDRS-TMS). A high interrater reliability is desirable to monitor symptom progression. Therefore, a teaching video and a system for annual online certification has been developed and implemented. Objectives The aim of this study is to investigate the interrater reliability of the UHDRS-TMS and of its subitems, and to examine the performance of raters in consecutive years. Methods Data from the online UHDRS-TMS certification were used. The interrater reliability was assessed for all first-time participants (n = 944) between 2009 and 2016. Intraclass correlation coefficients (ICC) were calculated for each year separately and the mean was taken as the total ICC. Results The UHDRS-TMS (ICC = 0.847), tandem walking (0.824), pronate/supinate hands left (0.713), and retropulsion pull test (0.706) showed good interrater reliability. Poor interrater reliability was found for maximal dystonia of the left and right upper extremity (0.187 and 0.322, respectively), maximal dystonia of the left and right lower extremity (0.200 and 0.256, respectively), and maximal dystonia of the trunk (0.389), tongue protrusion (0.266), and rigidity arms left (0.390). Raters performed significantly worse on follow-up certification compared to their first certification. Conclusions Our results suggest that the rating of dystonia (absent, slight, mild, moderate, or marked) is subjective and difficult to interpret, especially on video. Therefore, changing the dystonia items of the UHDRS-TMS should be explored. We also recommend that raters should watch the UHDRS-TMS teaching video before each certification.

The compromise of quality of life in Huntington's disease is a major issue, both for individuals with the disease as well as for their caregivers. The International Parkinson and Movement Disorder Society commissioned a review of the use and clinimetric validation status of measures used in Huntington's disease to assess aspects related with quality of life and to make recommendations on their use following standardized criteria. We included both patient‐centered measures (patient health‐related quality‐of‐life measures) and caregiver‐centered measures (caregiver quality‐of‐life measures). After conducting a systematic literature search, we included 12 measures of patient health‐related quality of life and 2 measures of caregiver quality of life. Regarding patient‐centered measures, the Medical Outcomes Study 36‐Item Short‐Form Health Survey is “recommended” as a generic assessment of health‐related quality of life in patients with Huntington's disease. The 12‐Item Short Form Health Survey, the Sickness Impact Profile, the 12‐item World Health Organization Disability Assessment Schedule, and the Huntington's Disease Health‐Related Quality of Life questionnaire are “suggested.” No caregiver‐centered quality‐of‐life measure obtained a “recommended” status. The Alzheimer's Carer's Quality of Life Inventory and the Huntington's Disease Quality of Life Battery for Carers are “suggested.” Recognizing that the assessment of patient health‐related quality of life can be challenging in Huntington's disease, as patients may lack insight and there is insufficient clinimetric testing of these scales, the committee concluded that further validation of currently available health‐related quality‐of‐life measures should be undertaken, namely, those Huntington's disease–specific health‐related quality‐of‐life measures that have recently been reported and used.

Parkinson's disease (PD) patients frequently suffer from dexterous deficits impeding activities of daily living. There is controversy whether impaired fine motor skill may stem from limb kinetic apraxia (LKA) rather than bradykinesia. Based on classical models of limb praxis LKA is thought to result when premotor transmission of time-space information of skilled movements to primary motor representations is interrupted. Therefore, using functional magnetic resonance imaging (fMRI) we tested the hypothesis that dexterous deficits in PD are associated with altered activity and connectivity in left parieto-premotor praxis network. Whole-brain analysis of fMRI activity during a task for LKA (coin rotation) showed increased activation of superior and inferior parietal lobule (SPL, IPL) and ventral premotor cortex (vPM) in PD patients compared to controls. For bradykinesia (assessed by finger tapping) a decreased fMRI activity could be detected in patients. Additionally, psychophysical interaction analysis showed increased functional connectivity between IPL and the posterior hippocampi in patients with PD. By contrast, functional connectivity to the right dorsolateral prefrontal cortex was decreased in patients with PD compared to controls. In conclusion, our data demonstrates that dexterous deficits in PD were associated with enhanced fMRI activation of the left praxis network upstream to primary motor areas, mirroring a neural correlate for the behavioral dissociation of LKA and bradykinesia. Furthermore, the findings suggest that patients recruit temporal areas of motor memory as an attempt to compensate for impaired motor skills. Finally, dysexecutive function may contribute to the deficit., Highlights • Impaired dexterity is related to a defective praxis network in PD. • The findings support the concept of an underlying limb kinetic apraxia. • Recruitment of temporal areas may reflect compensatory recall of motor engrams. • Dysexecutive control in PD may contribute to impaired motor skill.

International audience; The European Huntington's Disease Network (EHDN) commissioned an international task force to provide global evidence-based recommendations for everyday clinical practice for treatment of Huntington's disease (HD). The objectives of such guidelines are to standardize pharmacological, surgical and non-pharmacological treatment regimen and improve care and quality of life of patients. A formalized consensus method, adapted from the French Health Authority recommendations was used. First, national committees (French and English Experts) reviewed all studies published between 1965 and 2015 included dealing with HD symptoms classified in motor, cognitive, psychiatric, and somatic categories. Quality grades were attributed to these studies based on levels of scientific evidence. Provisional recommendations were formulated based on the strength and the accumulation of scientific evidence available. When evidence was not available, recommendations were framed based on professional agreement. A European Steering committee supervised the writing of the final recommendations through a consensus process involving two rounds of online questionnaire completion with international multidisciplinary HD health professionals. Patients' associations were invited to review the guidelines including the HD symptoms. Two hundred and nineteen statements were retained in the final guidelines. We suggest to use this adapted method associating evidence base-medicine and expert consensus to other rare diseases.

Background Pallidal deep brain stimulation (DBS) has shown to be beneficial in patients with advanced levodopa-responsive Parkinson's disease (PD) in several short-term studies. However, reported long-term outcomes of pallidal DBS for PD are limited and contradictory. Methods Eighteen consecutive PD patients were treated with unilateral or bilateral stimulation of the internal part of the globus pallidus (GPi). Assessments were carried out before and six months after neurosurgery, and annually thereafter for up to 16 years (mean follow-up time: 6 years). Primary outcomes included motor signs (Unified PD Rating Scale [UPDRS]-III), activities of daily living (ADL, UPDRS-II), and levodopa-induced motor complications (UPDRS-IV). Results The results show that GPi stimulation improves levodopa-responsive PD motor signs (UPDRS-III), levodopa-induced motor complications (UPDRS-IV), and ADL (UPDRS-II) in advanced PD. Among motor signs, tremor showed the best response to pallidal stimulation. Levodopa-induced motor complications and tremor showed improvements for more than 10 years after neurosurgery. Conclusions The overall findings in our cohort demonstrate that pallidal stimulation is effective in reducing parkinsonian motor signs (UPDRS-III), particularly in the ‘off’-medication state. Although the beneficial effects on bradykinesia, rigidity and ADL may be limited to 5–6 years, the follow up results indicate that the improvements of levodopa-induced motor complications (UPDRS-IV) and tremor can be sustained for more than 10 years.

BACKGROUND AND PURPOSE Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder with varied prevalence in different populations, which may be associated with specific haplotypes. This study aimed to explore the haplotypes encompassing the HTT gene in the Chinese population. METHODS A total of 406 individuals with HD and 59 normal relatives from 253 families with HD were enrolled. A total of 29 tag single nucleotide polymorphisms (tSNPs) were selected and genotyped for the haplotype analysis. RESULTS In stage one, we used 18 tSNPs to replicate the distribution of three major haplogroups (A, B, C). We found that risk-associated haplogroup variants A1 and A2, enriched on Caucasian HD chromosomes, were totally absent from both Chinese HD and control chromosomes, and the distributions of haplogroups between HD and control chromosomes were similar. Therefore, in stage two, we used 29 tSNPs (including the18 tSNPs) to define new haplogroups (I, II, III) and found that haplogroup I accounted for 61.4% on HD chromosomes and 34.4% on control chromosomes, indicating that haplogroup I was enriched on Chinese HD chromosomes. CONCLUSIONS This is the first haplotype analysis encompassing HTT in the Chinese population. The results contribute to explaining the low prevalence of HD in China and provide a better understanding of genetic diversity in the HTT region.

Huntington's disease (HD) is a neurodegenerative disease caused by the expansion of unstable CAG repeats in the HTT gene. There are scarce data about HD in China. Fifty-eight HD patients were consecutively recruited and assessed using the Unified HD Rating Scale (UHDRS) motor section and UHDRS behaviour assessment (UHDRS-b). Genetic analyses were also conducted. Thirty-three women and Twenty -five men were diagnosed with a mean age of 46.1 ± 11.2 years and a mean number of CAG triplet repeats 44.6 ± 4.4. CAG triplet repeat number was negatively correlated with age at onset, and positively correlated with UHDRS-b total score, and its subdomains including depressed mood, low self-esteem, anxiety and irritability. On the other hand, negative correlations were identified between age at onset and UHDRS-b total score, and its subdomains include low self-esteem, anxiety, suicidal thought, irritability and apathy. Disease durations were correlated with UHDRS motor scores and anxiety domain of UHDRS-b. This is the largest series of Chinese HD patients with demographic, clinical and genetic data confirms the demographic features of Chinese HD patients are comparable to those in other ethnic backgrounds. CAG triplet repeat number may also predict the severity of behaviour problems in HD patients besides its predication for age of onset.

Background Huntington's Disease (HD) is characterized by motor, cognitive and psychiatric dysfunction. Functional MRI (fMRI) provides new insight into the pathologic mechanism underlying the cognitive symptoms. Previous fMRI studies of HD focused on functional synchronization of various brain areas by measuring functional connectivity, a method that is unable to identify regional intrinsic neural activity changes in the brain. To fill in this gap, we utilized amplitude of low frequency fluctuations (ALFF). Objective To investigate alterations in regional brain activity and their association with clinical characteristics in the early stages of HD. Methods Ten early stage HD patients and 20 age- and sex-matched healthy controls were scanned to obtain imaging data. HD patients were assessed with the Unified Huntington's Disease Rating Scale, Mini-Mental State Exam (MMSE), Stroop test, Symbol Digit Modalities Test (SDMT), Verbal Fluency Test and Beck Depression Index. Results Gray matter volume (GMV) reduction was detected in bilateral striatum and left calcarine cortex in the HD group. After correcting for GMV, HD patients demonstrated significantly decreased ALFF in the right precuneus and angular gyrus, and increased ALFF in bilateral inferior temporal gyrus (ITG) and left superior frontal gyrus. Increased mean values of ALFF in the left ITG were correlated with worse performance in SDMT, and decreased mean values of ALFF in the precuneus were correlated with worse performance in the Stroop test and SDMT. Conclusions Our results suggest that intrinsic brain activity alterations in the precuneus and cortico-striatal circuit may be the mechanism underlying impaired cognition in early HD.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder in which a nuclear mutation of the thymidine phosphorylase (TP) gene causes mitochondrial genomic dysfunction. Patients suffer from gastrointestinal dysmotility, cachexia, ptosis, external ophthalmoparesis, myopathy and polyneuropathy. Magnetic resonance imaging (MRI) shows leukoencephalopathy. We describe clinical, genetic and neuroradiological features of three brothers affected with MNGIE. Clinical examination, laboratory analyses, MRI and magnetic resonance spectroscopy (MRS) of the brain, and genetic analysis have been performed in all six members of the family with the three patients with MNGIE. Two of them are monozygous twins. They all suffered from gastrointestinal dysmotility, cachexia, ophthalmoplegia, muscular atrophies, and polyneuropathy. Urinary thymidine was elevated in the patients related to the severity of clinical disease, and urinary thymidine (normally not detectable) was also found in a heterozygous carrier. Brain MRI showed leukoencephalopathy in all patients; however, their cognitive functioning was normal. Brain MRS demonstrated reduced N-acetylaspartate and choline in severely affected areas. MRI of heterozygous carriers was normal. A new mutation (T92N) in the TP gene was identified. Urinary thymidine is for the first time reported to be detectable in a heterozygous carrier. MRS findings indicate loss of neurons, axons, and glial cells in patients with MNGIE, but not in heterozygous carriers.

Background Multiple sclerosis (MS) has been associated with deficits in social cognition. However, little is known about which domains of social cognition are predominantly affected and what other factors are associated with it. Objectives 1) To characterize social cognition deficit in a group of MS outpatients. 2) To relate impairment in social cognition to overall cognitive status, depression and fatigue. Methods Thirty-five MS patients (mean disease duration 12.9 years, median EDSS 3) and thirty-four healthy controls (HCs) were examined using the German version of the Geneva Social Cognition Scale to measure different domains of social cognition. Standard neuropsychological testing was applied to all patients and to 20 HCs. Patient-reported outcomes included questionnaires for fatigue, depression, anxiety and executive-behavioural disturbances. Results The mean social cognition raw score was lower in the MS patients compared to the HCs (86.5±8.7 vs. 91.2±5.9 p=0.005; d=0.6) and did not correlate with EDSS or disease duration. The difference was driven by facial affect recognition and the understanding of complex social situations (14% and 23% of patients under the cut-off, respectively). The impairment in these two tasks did not correlate with general cognitive performance or depression but with fatigue. Conclusions The impairment in our group was restricted to high order and affective social cognition tasks and independent of general cognitive performance, EDSS, disease duration and depression. Fatigue correlated with social cognition performance, which might be due to common underlying neuronal networks. This article is protected by copyright. All rights reserved.

Background Previous studies on human brain tissue alterations caused by deep brain stimulation described glial and reactive inflammatory changes. In the current pathoanatomical study, we extended the analysis to signs of axonal changes and the influence of concomitant disease. Methods Brains of 10 patients with Parkinson's disease or essential tremor and a total of 18 electrodes were systematically examined up to 7.5 y after surgery. Results In general, tissue that had long-term contact with the electrode material exhibited astrogliosis in all, T-lymphocytes in 93%, and multinucleated giant cells in 68% of patients. Immunohistochemistry showed an increase in amyloid precursor protein immunoreactive axonal swellings in the brain at the electrically active parts of the electrodes. Patients who died of septicemia showed a more severe astrogliosis and giant cell reaction than patients who died of cardiovascular events. Parkinson's disease or essential tremor did not differentially produce histopathological changes around the electrodes. Conclusion Long-term electrical stimulation by deep brain stimulation causes minor axonal changes. The cause of death, but not the underlying neurological disease, affects the histopathological changes around the electrode. The findings need to be reproduced by examining larger patient subgroups. © 2015 International Parkinson and Movement Disorder Society

BACKGROUND AND PURPOSE Huntington's disease (HD) is a chronic progressive neurodegenerative disorder with a long presymptomatic period that opens a window for potential therapies aimed at neuroprotection. Neuroimaging offers the potential to monitor disease-related progression of the disease burden (DB) using model-based magnetization transfer imaging. MATERIALS AND METHODS We have conducted a cross-sectional study to stratify healthy age-matched controls, premanifest and symptomatic HD patients (n = 30) according to their macromolecular depositions in the caudate nucleus. We employed a binary spin-bath magnetization transfer (MT) method for a quantitative description of macromolecule deposits and interactions with their adjacent environment. RESULTS A region-of-interest based fuzzy clustering analysis identified representative clusters for several stages of the disease course related to its progression: one cluster represented subjects with a high DB 230 and healthy controls. Three further clusters represented transition zones between both DB levels (230-268) consisting of presymptomatic carriers with DB values increasing with decreasing distance from the cluster that indicated low DB and healthy age-matched controls. CONCLUSION The proposed binary spin-bath MT method offers the potential to monitor DB and progression in HD. The method may augment qualitative MT techniques since it depicts tissue changes related to interactions between macromolecules and protons in disease specific brain regions that follow the neurodegenerative process.

BACKGROUND: Understanding the relation between predominantly choreatic and hypokinetic-rigid motor subtypes and cognitive and general functioning may contribute to knowledge about different motor phenotypes in Huntington's disease. METHODS: In the European Huntington's Disease Network Registry study, 1882 subjects were classified as being predominantly choreatic (n?=?528) or hypokinetic-rigid (n?=?432), according to their scores on items of the total motor score a priori labeled as choreatic or hypokinetic-rigid; the other 922 patients were of a mixed type. The relationship between motor type and cognitive (verbal fluency, symbol digit modalities, Stroop color, word and interference tests) and functional (total functional capacity) capacity was investigated using multiple linear regression. RESULTS: Motor subtype contributed significantly to the total functional capacity score (partial r(2) : 7.8%; P?.001) and to the 5 cognitive scores (partial r(2) ranged from 2.0% to 8.4%; all P?

Background The deletion mutation of glutamate codon (GAG) in the TOR1A gene is a major cause of primary generalized dystonia. Recent genetic studies suggest that the rs1182 polymorphism in the same gene may represent a risk factor for primary dystonia. However, this finding has been inconsistent. Furthermore, no data on such an association in a Chinese population have been published. Methods A total of 291 patients with primary dystonia from the Department of Neurology, West China Hospital of Sichuan University were included. From the same region, 294 healthy individuals were recruited as a control group. The SNP was identified by polymerase chain reaction–restriction fragment length polymorphism. Results In the present study, focal dystonia was the most common presented form. No difference was found in the genotype frequency, minor allele frequencies, and “G” allele frequency between all dystonia patients and controls. No difference was found either, between early- and late-onset dystonia patients, patients with and without a positive family history, patients with pain and without pain, and patients with and without sensory trick. Moreover, no significant differences in the genotype and allele frequencies were found among different dystonia subtypes. Conclusion No association of the rs1182 of TOR1A with Chinese primary dystonia was found. More studies on such an association involving a larger number of participants, especially from Asian populations, are needed to confirm the present findings.

Background Diffusion tensor imaging (DTI) could detect abnormal brain microstructural alterations. DTI studies of Huntington's Disease(HD) have yielded inconsistent results. Objective To integrate the existing DTI studies of HD and explore the validity of DTI to detect microstructural damages in HD brain via meta-analysis. Methods Systematic and comprehensive searches of the databases were performed for DTI studies of HD. The data from the studies that met our inclusion criteria were extracted and analyzed using the CMA2 software. Random effect models were utilized to minimize the potential between-study heterogeneity. One-way sensitivity analysis was conducted to test the robustness of the results. Results The meta-analysis included 140 pre-symptomatic HD (PreHD), 235 symptomatic HD (SymHD) patients and 302 controls, revealing significantly increased fractional anisotropy (FA) in the caudate, putamen, and globus pallidus, while decreased FA in the corpus callosum of both PreHD and SymHD patients compared with controls. In addition, significantly increased mean diffusivity (MD) was identified in the putamen and thalamus of both PreHD and SymHD patients, and in the caudate of SymHD patients, while no significant difference in MD in the caudate of PreHD patients. In the corpus callosum, there was a significant increase of radial diffusivity and axial diffusivity in SymHD patients compared with controls. Meta-regression showed gender-based difference in MD values of the caudate. Conclusions Our meta-analysis provides further evidence that DTI detects microstructural damage of both white matter and gray matter even in PreHD gene carriers. MD is less sensitive than FA in detecting structural changes in PreHD.

Background: Clinical presentation and DYT1 status amongst Chinese patients with primary dystonia have not been well studied. Methods: One hundred and twenty patients with primary dystonia from South-West China were studied in a prospective survey for 3.5 years. Severity and the resulting disability were assessed using the Burke–Fahn–Marsden dystonia rating scale (BFMDRS). Health related quality of life (HRQL) was measured through the 36-item short-form (SF-36). The Hospital Anxiety and Depression Scale (HADS) was utilized to identify and quantify depression and anxiety. Mutations in the DYT1 exon 5 were screened by direct sequencing. Results: Cervical dystonia was found to be the most frequent form of focal dystonia and was discovered to occur at an early age. Pain and tremor were the common associated symptoms. Family history was positive in 19.5% of the cases, with a trend of earlier onset. Depression (14.5%) and anxiety (6.6%) were the main HRQL impairments. Multiple linear regression analysis suggested that gender, depression, anxiety and functional disability were amongst the principal determinants of lower HRQL. Only one instance of DYT1 GAG deletion (1.4%) was detected in 71 patients. Conclusion: Our data on a cohort of Chinese patients show some difference from descriptions in other ethnic groups. This includes an earlier age of onset, a lower incidence of depression and female serving as a predictor factor of a HRQL. Similar to other cohorts, DYT1 gene mutations are rare.

Mutations in LRRK2, the gene that encodes leucine-rich repeat kinase 2 (LRRK2), are associated with autosomal dominant and sporadic forms of Parkinson's disease (PD) and are the most common genetic causes of PD. Recently, a R1628P variant has been reported as a risk factor for PD in Taiwan and Singapore. To determine the association of this variant and PD in the Han-Chinese population from mainland China, we analyzed its frequency in a cohort of 600 patients and 459 unrelated healthy controls. Forty (6.7%) patients were heterozygous and 3 (0.5%) homozygous for the R1628P variant, which was significantly more frequent than in the controls [2.4% heterozygous and 0.0% homozygous, Odds ratio = 3.14, 95%CI: 1.60-6.17, P < 0.01]. Considering the age at onset, this difference was found only in late-onset PD (older than 50) [Odds ratio = 3.76, 95% CI: 1.90-7.45, P < 0.01]. Our data confirms that the LRRK2 R1628P variant is associated with an increased risk to develop late onset PD in the ethnic Han-Chinese population.

In a Chinese myoclonus-dystonia syndrome (MDS) family presented with a phenotype including a typical MDS, cervical dystonia, and writer's cramp, genetic analyses revealed a novel 662 + 1insG heterozygous mutation in exon 5 in the epsilon-sarcoglycan (SGCE) gene, leading to a frameshift with a down stream stop codon. Low SGCE mRNA levels were detected in the mutation carriers by real-time PCR, suggesting that the nonsense mutation might interfere with the stability of SGCE mRNA. This is the first report on Chinese with a SGCE mutation leading to MDS. Our data support the fact that same mutation of SGCE gene can lead to a varied phenotype, even in the same family.

Dopamine deficiency in Parkinson's disease leads to numerous molecular changes in basal ganglia. However, the consequences of these changes on the motor cortex remain unclear. Here we show that the immunoreactivity of parvalbumin, which is expressed in GABAergic interneurons, increases in the primary motor cortex of parkinsonian rats. This increase can be reversed by a subsequent lesion of the subthalamic nucleus. These results suggest that dopamine deficiency induces reversible changes in GABAergic cortical cells, which might be linked with parkinsonian symptoms.

Primary dystonia is a movement disorder characterized by involuntary and sustained muscle contractions causing twisting or abnormal postures and mutations in several genes have been identified. Our goal was to investigate, whether the clinical presentation would differ between patients with a positive family history, and patients without. Furthermore, we have performed mutation analysis in the subgroup of patients with a positive family history. A total of 175 patients with primary dystonia were evaluated. Data on gender, presence and frequency of pain and tremor, age of onset, and the distribution of affected body parts were compared between patients with positive and negative family history. All exons of the torsion dystonia 1, GTP cyclohydrolase 1 and epsilon-sarcoglycan genes were examined in 40 patients by SSCP analysis of PCR products followed by sequencing of variant conformers. Dystonia patients with a positive family history of dystonia had an earlier age of onset and those with a positive family history of tremor more often associated tremor than those with a negative family history. Four new polymorphisms in the epsilon-sarcoglycan gene were found and others confirmed, but no known or new mutations could be detected. Our study supports the notion that primary dystonia is a genetically heterogeneous disease.

Background The etiology of primary dystonia remains unclear. Recent genetic studies suggest that the Val66Met polymorphism of the BDNF gene is a genetic modifier in cranial–cervical dystonia in Caucasians. However, the finding is not consistent. Patients and Methods A total of 193 patients with primary cranial–cervical dystonia from the Department of Neurology, West China Hospital of Sichuan University was included. From the same region, 216 healthy individuals were recruited as a control group. The Val66Met SNP was identified by polymerase chain reaction-restriction fragment length polymorphism. Results In the present study, cervical dystonia (59.59%) was the most common type of primary cranial–cervical dystonia. No significant difference was found in the genotype and minor allele frequencies between all patients and controls, between cervical dystonia patients and controls, and between craniocervical dystonia patients and controls. However, significant differences were found in the genotype and minor allele frequencies of Val66Met SNP between blepharospasm (BSP) patients and controls ( P = 0.0080 and P = 0.0042, respectively), and between BSP patients and patients with craniocervical derived from BSP ( P = 0.0010 and P = 0.0002, respectively). Conclusion Minor allele “A” of BDNF Val66Met SNP may increase the risk for developing BSP and may be a protective factor for preventing BSP progressing to craniocervical dystonia. More association studies involving a larger number of participants are needed to confirm the present findings.

Dystrophin and associated proteins form a complex with an important role at the sarcolemma. Expression of this protein complex is highly regulated during development and regeneration. In order to better understand assembling patterns of these proteins, we have studied their expression in targetoid-like phenomena found in human muscle after chronic denervation, a situation known to give rise to abnormal protein trafficking. In eight biopsies of patients with chronic denervation, mainly resulting from amyotrophic lateral sclerosis, we found a number of targetoid phenomena. Selective accumulation of a number of sarcolemmal and sarcoplasmatic proteins occurred in targetoid phenomena. The larger majority of them contained gamma-sarcoglycan (gammaSG), but none contained the developmental heavy chain myosin isoform. In a series of 166 targetoid phenomena which could be studied with 17 different antibodies recognizing sarcolemmal and cytoplasmatic proteins, a high level of colocalization of gammaSG with desmin and alpha-actinin was found. Colocalization rate was much lower with other proteins, including other members of the dystrophin-associated protein complex. These data show that selective changes in expression of otherwise closely related proteins occur during disturbed trafficking leading to target formation. Because members of the dystrophin-associated protein complex do not accumulate in a similar fashion within targets, we suggest that a complex molecular control of gene expression and trafficking of this complex is involved after chronic muscle denervation.

Huntington's disease typically presents with involuntary movements, cognitive decline and behavioural abnormalities; however, new data show a greater spectrum and more complexity in the mode of presentation than previously appreciated. On one hand efforts are under way to better assess all aspects of the evolving phenotype over the course of the disease, on the other hand large cohorts have been prospectively followed-up and similar efforts are now being started in China. In this communication, we briefly review the most salient findings from the last couple of years. The recently established large cohorts allow the performance of accurate studies examining correlation of genetic polymorphisms with specific aspects of the phenotype thus allowing for some mechanistic insight into the causes of phenotypic variation. While Huntington's disease is the most frequent hereditary cause of chorea, other disorders with similar clinical phenotypes, including neuroacanthocytosis, are now better known, including a better understanding of the primary cause as well as the pathophysiology at the molecular level. Studies on the mechanisms of disease in these different disorders may shed light on the respective pathomechanisms and may open new approaches to a better understanding and additional treatment options for choreatiform neurodegenerative disorders.

The D216H single-nucleotide polymorphism (SNP) (rs1801968) in DYT1 exon 4 has been suggested to be a genetic modifier in primary dystonia.

Background Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative diseases. Mutations in the spastin (SPAST) gene are the most common cause of pure HSP. However, few data are available regarding the clinical and genetic spectrum of HSP among Chinese patients. Methods Clinical data were collected at diagnosis and follow-up of 42 Chinese patients with pure HSP. All seventeen exons of the SPAST gene were directly sequenced. Additionally, we used a multiplex ligation dependent probe amplification (MLPA) assay targeting the SPAST gene to evaluate large exon deletion or insertion mutations in patients without SPAST point mutations. Results The age of disease onset of our patients was 19.6 ± 14.4 years. Six novel variations were found, including three missense mutations (p. L363P, p. D441V, and p. S595R), one insertion (c.1511dupT (p. Y505Ifs*7)), and two larger deletions (exons 5–17 and exons 10–17). Four previously reported mutations, including p. S399L, c.1215_c.1219delTATAA (p. N405Kfs*36), exon 1 deletion, and exon 16 deletion, were detected. The SPAST mutation rate was 40% (4/10) in Chinese familial patients and 33.33% (7/21) in Chinese sporadic pure HSP patients. The frequency of large deletions was high in both AD-HSP (20%, 2/10) and sporadic HSP (14.28%, 3/21). Conclusion SPAST mutations are common in Chinese patients with pure HSP. Large exon deletions are an important cause of AD-HSP and sporadic pure HSP in Chinese patients. Large fragment tests should be performed to explore large SPAST mutations in familial and sporadic HSP patients without SPAST point mutations.

Myotonia congenita is a human muscle disorder caused by mutations in CLCN1, which encodes human chloride channel 1 (CLCN1). Zebrafish is becoming an increasingly useful model for human diseases, including muscle disorders. In this study, we generated transgenic zebrafish expressing, under the control of a muscle specific promoter, human CLCN1 carrying mutations that have been identified in human patients suffering from myotonia congenita. We developed video analytic tools that are able to provide precise quantitative measurements of movement abnormalities in order to analyse the effect of these CLCN1 mutations on adult transgenic zebrafish swimming. Two new parameters for body-wave kinematics of swimming reveal changes in body curvature and tail offset in transgenic zebrafish expressing the disease-associated CLCN1 mutants, presumably due to their effect on muscle function. The capability of the developed video analytic tool to distinguish wild-type from transgenic zebrafish could provide a useful asset to screen for compounds that reverse the disease phenotype, and may be applicable to other movement disorders besides myotonia congenita.

In addition to vascular and supraspinal influences, contraction of craniofacial muscles or central sensitization processes following continuous nociceptive input of craniofacial muscles may play an important role in the pathogenesis of tension-type headache. Chemodenervation induced by botulinum toxin injection is successfully used to decrease muscle tension. If muscle tension is important in this type of headache, then botulinum toxin could be helpful in its treatment. We conducted a randomized, placebo-controlled study to examine the effect of 20 U botulinum toxin injected into frontal and temporal muscles in patients with chronic tension-type headache. During a baseline of 4 weeks and a posttreatment period of 8 weeks, the effect was evaluated with daily records and the West Haven-Yale Multidimensional Pain Inventory. Some improvement in affective variables were demonstrated in the botulinum group, but important outcome variables, such as pain intensity, the number of pain-free days, and consumption of analgesics, were not statistically different between the groups. Reasons for these moderate effects may include the injection sites, dose of botulinum toxin, and duration of treatment.

The aim of the study was to investigate force regulation in patients with writer's cramp when performing a drawer-opening task using the precision grip. Experimental conditions included intervening load pulses and vibratory manipulations for examining grip force responses to sensory disturbances. The data revealed that grip force was increased in patients with writer's cramp compared with normal subjects, with a stronger modulation in the symptomatic compared with the asymptomatic hand. This denotes a change in force scaling capabilities and most notably for the preferred hand used in manipulative activities. Vibratory stimulation of the extrinsic hand/finger muscles resulted in an increased grip force of both hands in the patients with writer's cramp. The latter was not observed in normal subjects and supports a bilateral dysfunction in sensorimotor integration resulting from focal dystonia. In conclusion, the disturbed regulation of the precision grip during a drawer-opening task is illustrative for the inability of patients with writer's cramp to efficiently control the force output during manipulative activities.

The primary objective of this study was to assess the effect of tolcapone on levodopa dosage in parkinsonian patients whose 'wearing-off' phenomenon has been controlled with more frequent levodopa dosage. After a 1-week placebo run-in, 97 patients were assigned randomly to receive placebo or tolcapone 200 or 400 mg three times daily (t.i.d.). Levodopa dosage was reduced by ~ 35% on day 1 of study and subsequently retitrated as required. After 6 weeks, the tolcapone groups crossed over to receive the other dose for a further 3 weeks for exploratory purposes. Both tolcapone groups had greater reductions in levodopa dosage than the placebo group at week 6 (not statistically different). The 200-mg t.i.d. group showed greatest improvement in estimated mean scores for all efficacy parameters (p < 0.05 versus placebo for change in Unified Parkinson's Disease Rating Scale Subscale II). Fewer dopaminergic and nondopaminergic adverse events were associated with tolcapone 200 mg t.i.d. than with tolcapone 400 mg t.i.d. The most frequently reported dopaminergic adverse events were nausea, cramps, dyskinesia, and dystonia. The most frequently reported unanticipated adverse event was diarrhea. Tolcapone 200 mg t.i.d. may provide additional benefit to patients with moderately advanced Parkinson's disease with treated 'wearing-off' phenomenon.

The management of patients with chorea, in particular Huntington’s disease, is a complex task requiring skills in a number of areas. This paper reviews new knowledge on this topic and places it in the context of established procedures. It is focused on Huntington’s disease, since this is the disorder, for which most publications on management have been published in the past few years. Management starts with appropriate diagnosis and differential diagnosis, with the aim of finding disorders with chorea amenable to causative treatment. The place of genetic testing and the importance of genetic counselling is stressed, as well as the importance of precise observation in the course of the disorder to tailor appropriate therapies. Pharmacological treatment is based on poor evidence but to a large extent on expertise from centres devoted to the care of patients with Huntington’s disease. It is focused mainly on motor and psychiatric aspects of the phenotype. Nonpharmacological treatment is important and is best offered in a multidisciplinary care setting.

Background and purpose Proline-rich transmembrane protein 2 (PRRT2) has recently been identified as a causative gene of paroxysmal kinesigenic dyskinesia (PKD). However, the frequencies of its mutations and their correlation with the clinical features of PKD remain largely unknown. Methods Four exons of PRRT2 in 33 patients with PKD from Southwest China were screened by direct sequencing in this study. Results The mean onset age of the patients was 12.50 ± 2.70 years. Sixteen patients (48.48%) had sensory aura before their attacks. In total, 66.67% of the patients were running when the attacks occurred. c.649_650insC (p.P217fsX7), the most commonly reported insertion mutation, was identified in nine patients (27.27%). Conclusions Other genes are involved in the development of PKD, but PRRT2 is a common causative gene for patients with PKD from Southwest China.

Chorea-acanthocytosis is a rare autosomal recessive disorder. To date, treatment is only symptomatic and supportive. Results from the few reports of chorea-acanthocytosis patients treated with deep brain stimulation (DBS) have been inconsistent. We present case reports for two patients with chorea-acanthocytosis who received DBS treatment and compare the outcomes with results from the literature. Both patients showed the typical clinical features of chorea-acanthocytosis with motor symptoms resistant to medical treatment. Chorea was significantly improved following low-frequency DBS treatment in both patients. However, dystonia was only mildly improved. Four chorea-acanthocytosis patients treated with DBS treatment have been reported in the literature. One patient had improvement with low-frequency DBS stimulation, while another two had improvement with higher-frequency DBS. One patient, however, did not improve with either low-frequency or high-frequency DBS. Bilateral DBS to the GPi can improve chorea and dystonia in some patients with intractable chorea-acanthocytosis. However, selection criteria for the most promising candidates must be defined, and the long-term benefits evaluated in clinical studies.

In many patients, optimal results after pallidal deep brain stimulation (DBS) for primary dystonia may appear over several months, possibly beyond 1 year after implant. In order to elucidate the factors predicting such protracted clinical effect, we retrospectively reviewed the clinical records of 44 patients with primary dystonia and bilateral pallidal DBS implants. Patients with fixed skeletal deformities, as well as those with a history of prior ablative procedures, were excluded. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores at baseline, 1 and 3 years after DBS were used to evaluate clinical outcome. All subjects showed a significant improvement after DBS implants (mean BFMDRS improvement of 74.9% at 1 year and 82.6% at 3 years). Disease duration (DD, median 15 years, range 2-42) and age at surgery (AS, median 31 years, range 10-59) showed a significant negative correlation with DBS outcome at 1 and 3 years. A partition analysis, using DD and AS, clustered subjects into three groups: (1) younger subjects with shorter DD (n = 19, AS 17, AS ? 27). Younger patients with short DD benefitted more and faster than older patients, who however continued to improve 10% on average 1 year after DBS implants. Our data suggest that subjects with short DD may expect to achieve a better general outcome than those with longer DD and that AS may influence the time necessary to achieve maximal clinical response.

Background A functional SNP (rs9347683) in the promoter region of the parkin gene had been implicated as a risk factor in older Parkinson's disease (PD) patients. Methods Using a case–control methodology, we genotyped the SNP in the promoter region of the parkin gene to investigate their association with risk of PD and conducted a pooled analysis of published papers in the English literature. Results A total of 1087 study subjects comprising 595 patients with PD and 492 unrelated healthy controls were recruited. The frequency of “GG” genotype in the elderly sub-group (≥ 65 years) was higher in PD compared to controls (OR = 1.11) though we did not observe any difference in allele or genotype frequencies between the cases and the controls (P > 0.05) in the overall PD population. Those with genotype “GG” were associated with a higher Hoehn–Yahr stage compared with PD patients carrying “GT” + “TT” (P = 0.040). A pooled analysis involving more than > 3000 subjects revealed that the frequency of genotypes in PD patients did not differ from the controls (OR = 0.98, 95% CI: 0.86–1.12). However, in the group ≥ 65 years of age, the “GG” genotype was higher in PD (OR = 1.51, 95% CI: 1.06–2.13, P = 0.020) among the ethnic Chinese. Conclusions While we did not demonstrate a significant association of the parkin promoter polymorphism with PD in our sample, the pooled data suggest that the variant may increase the risk of PD in the more elderly population among the ethnic Chinese, suggesting possible ethnicity-specific effect. Further in vitro and in vivo studies to evaluate this functional parkin variant are warranted.

Mutations in the gene encoding Leucine-rich repeat kinase 2 (LRRK2) have been recently linked with autosomal-dominant parkinsonism, and polymorphisms have been commonly associated with sporadic Parkinson's disease (PD). A p.2385GR variant has been reported as a risk factor for PD in Taiwan, Singapore and Japan. Herein, we have assessed the frequency of this polymorphism among the ethnic Han-Chinese population in a case-control study. A total of 600 patients with PD and 334 unrelated healthy controls were genotyped using PCR-restriction fragment length polymorphism analysis. Hardy-Weinberg equilibrium of each group was calculated, and differences in genotype frequencies between groups were assessed by the Chi-square test. In the PD cohort, 70 patients (11.7%) were heterozygous and 1 (0.2%) was homozygous for the p.2385GR variant. This was significantly more frequent than in the controls [3.3%, Odds ratio = 3.9, 95% confidence interval (CI) = 2.1-7.5, P0.01]. Clinically, the age of PD onset of the p.2385GR carriers was lower than the non-carriers (P = 0.01). Our study indicates that this LRRK2 p.2385GR substitution contributes to the development of PD in ethnic Han-Chinese population, which may play important implications for future study on molecular genetics and pathogenesis of PD.

We describe two Chinese families with a mild form of the myotonia congenita due to novel chloride channel (ClCN1) mutations. In one case, heterozygous I553F and H555N mutations were found. The patient shared the I553F mutation with his healthy father, and his mother had a history of mild myotonia when she was younger. In another family, autosomal dominant myotonia congenita was due to a L844F change. The physiological effects of the mutations were examined by using the two-electrode voltage-clamp technique after expression of the channels in Xenopus oocytes. All mutations drastically shifted the voltage required for half-maximal activation, more under conditions mimicking the homozygous situation, than under conditions mimicking the heterozygous situation. The larger effect was seen in the compound heterozygous situation combining the I553F and the H555N mutations. Our data suggest that myotonia congenita caused by CLCN1 mutations in Chinese have similar variable features to those found in the West.

OBJECTIVE: Deep brain stimulation (DBS) has emerged as a useful therapeutic option for patients with insufficient benefit from conservative treatment. METHODS: Nine patients with chronic DBS who suffered from cervical dystonia (4), generalized dystonia (2), hemidystonia (1), paroxysmal dystonia (1) and Meige syndrome (1) were available for formal follow-up at three years postoperatively, and beyond up to 10 years. All patients had undergone pallidal stimulation except one patient with paroxysmal dystonia who underwent thalamic stimulation. RESULTS: Maintained improvement was seen in all patients with pallidal stimulation up to 10 years after surgery except in one patient who had a relative loss of benefit in dystonia ratings but continued to have improved disability scores. After nine years of chronic thalamic stimulation there was a mild loss of efficacy which was regained when the target was changed to the pallidum in the patient with paroxysmal dystonia. There were no major complications related to surgery or to chronic stimulation. Pacemakers had to be replaced within 1.5 to 2 years, in general. CONCLUSION: DBS maintains marked long-term symptomatic and functional improvement in the majority of patients with dystonia.

The S218L CACNA1A mutation has been previously described in two families with familial hemiplegic migraine. We present three siblings with the mutation with the novel association of childhood seizures, and highlight the dynamic changes seen on electroencephalography during hemiplegic migraine attacks. Depressed activity contralateral to the hemiparesis was seen on electroencephalography during acute hemiplegic migraine attacks, which may be due to changes to calcium channels caused by the S218L mutation. Both parents were asymptomatic and did not carry the S218L mutation in their blood. This suggests the presence of mosaicism in the transmitting parent.