Search

Oculopharyngodistal myopathy (OPDM) is an adult-onset neuromuscular disease characterized by progressive ptosis, dysarthria, ophthalmoplegia, and distal muscle weakness. Recent studies revealed that GGC repeat expansions in 5'-UTR of LRP12, GIPC1, and NOTCH2NLC are associated with OPDM. Despite these advances, approximately 30% of OPDM patients remain genetically undiagnosed. Herein, we aim to investigate the genetic basis for undiagnosed OPDM patients in two unrelated Chinese Han families.Parametric linkage analysis was performed. Long-read sequencing followed by repeat-primed polymerase chain reaction and amplicon length polymerase chain reaction were used to determine the genetic cause. Targeted methylation sequencing was implemented to detect epigenetic changes. The possible pathogenesis mechanism was investigated by quantitative polymerase chain reaction, immunoblotting, RNA fluorescence in situ hybridization, and immunofluorescence staining of muscle biopsy samples.The disease locus was mapped to 12q24.3. Subsequently, GGC repeat expansion in the promoter region of RILPL1 was identified in six OPDM patients from two families, findings consistent with a founder effect, designated as OPDM type 4. Targeted methylation sequencing revealed hypermethylation at the RILPL1 locus in unaffected individuals with ultralong expansion. Analysis of muscle samples showed no significant differences in RILPL1 mRNA or RILPL1 protein levels between patients and controls. Public CAGE-seq data indicated that alternative transcription start sites exist upstream of the RefSeq-annotated RILPL1 transcription start site. Strand-specific RNA-seq data revealed bidirectional transcription from the RILPL1 locus. Finally, fluorescence in situ hybridization/immunofluorescence staining showed that both sense and antisense transcripts formed RNA foci, and were co-localized with hnRNPA2B1 and p62 in the intranuclear inclusions of OPDM type 4 patients.Our findings implicate abnormal GGC repeat expansions in the promoter region of RILPL1 as a novel genetic cause for OPDM, and suggest a methylation mechanism and a potential RNA toxicity mechanism are involved in OPDM type 4 pathogenesis. ANN NEUROL 2022;92:512-526.

BACKGROUND AND PURPOSE: In spastic paraplegia type 5, spinal cord atrophy and white matter signal abnormalities in the brain are the main MR imaging alterations. However, the specific mechanism remains unclear. We explored the microstructural changes occurring in spastic paraplegia type 5 and assessed the relation between MR imaging and clinical data. MATERIALS AND METHODS: Seventeen patients with spastic paraplegia type 5 and 17 healthy controls were scanned with DTI and T1 mapping on a 3T MR imaging scanner. Fractional anisotropy, mean diffusivity, radial diffusivity, axial diffusivity, and T1 values were obtained using Tract-Based Spatial Statistics and the Spinal Cord Toolbox. Neurofilament light and myelin basic protein in the CSF were measured. The differences in MR imaging and biochemical data between patients with spastic paraplegia type 5 and healthy controls were compared using the Student t test. RESULTS: A widespread reduction of fractional anisotropy values and an elevation of mean diffusivity, T1, and radial diffusivity values were found in most cervical, T4, and T5 spinal cords; corona radiata; optic radiations; and internal capsules in spastic paraplegia type 5. A variation in axial diffusivity values was shown only in C2, C6, and the corona radiata but not in the gray matter. The levels of neurofilament light and myelin basic protein were higher in those with spastic paraplegia type 5 than in healthy controls (myelin basic protein, 3507 [SD, 2291] versus 127 [SD, 219] pg/mL; neurofilament light, 617 [SD, 207] versus 265 [SD, 187] pg/mL; P

Despite the increasing number of genes associated with Charcot-Marie-Tooth (CMT) disease, many patients currently still lack appropriate genetic diagnosis for this disease. Autosomal dominant mutations in aminoacyl-tRNA synthetases (ARSs) have been implicated in CMT. Here, we describe causal missense mutations in the gene encoding seryl-tRNA synthetase 1 (SerRS) for 3 families affected with CMT.Whole-exome sequencing was performed in 16 patients and 14 unaffected members of 3 unrelated families. The functional impact of the genetic variants identified was investigated using bioinformatic prediction tools and confirmed using cellular and biochemical assays.Combined linkage analysis for the 3 families revealed significant linkage (Zmax LOD = 6.9) between the genomic co-ordinates on chromosome 1: 108681600-110300504. Within the linkage region, heterozygous SerRS missense variants segregated with the clinical phenotype in the 3 families. The mutant SerRS proteins exhibited reduced aminoacylation activity and abnormal SerRS dimerization, which suggests the impairment of total protein synthesis and induction of eIF2α phosphorylation.Our findings suggest the heterozygous SerRS variants identified represent a novel cause for autosomal dominant CMT. Mutant SerRS proteins are known to impact various molecular and cellular functions. Our findings provide significant advances on the current understanding of the molecular mechanisms associated with ARS-related CMT. ANN NEUROL 2022.

Primary familial brain calcification (PFBC) is a neurogenetic disorder characterized by bilateral calcified deposits in the brain. We previously identified that MYORG as the first pathogenic gene for autosomal recessive PFBC, and established a Myorg-KO mouse model. However, Myorg-KO mice developed brain calcifications until nine months of age, which limits their utility as a facile PFBC model system. Hence, whether there is another typical animal model for mimicking PFBC phenotypes in an early stage still remained unknown. In this study, we profiled the mRNA expression pattern of myorg in zebrafish, and used a morpholino-mediated blocking strategy to knockdown myorg mRNA at splicing and translation initiation levels. We observed multiple calcifications throughout the brain by calcein staining at 2–4 days post-fertilization in myorg-deficient zebrafish, and rescued the calcification phenotype by replenishing myorg cDNA. Overall, we built a novel model for PFBC via knockdown of myorg by antisense oligonucleotides in zebrafish, which could shorten the observation period and replenish the Myorg-KO mouse model phenotype in mechanistic and therapeutic studies.

Background Wilson disease is a rare, disabling, neurological genetic disease. Biomarkers of brain damage are less well developed. Objective The aim of this study was to evaluate the utility of plasma glial fibrillary acidic protein as a biomarker for neurological involvement in patients with Wilson disease. Methods This prospective cross-observational study compared plasma glial fibrillary acidic protein concentration among different subtypes of patients with Wilson disease and healthy control subjects. Plasma glial fibrillary acidic protein levels were measured in 94 patients and 25 healthy control subjects. Patients were divided into two subtypes: patients with neurological manifestations (n = 74) or hepatic manifestations (n = 20). Results Median levels of plasma glial fibrillary acidic protein were significantly elevated in patients with neurological manifestations (143.87 pg/mL) compared with those with hepatic manifestations (107.50 pg/mL) and healthy control subjects (86.85 pg/mL). Receiver operating characteristic curve revealed that a plasma glial fibrillary acidic protein cutoff value of 128.8 pg/mL provides sufficient sensitivity (80.0%) and specificity (63.5%) to differentiate patients with neurological manifestations from those with hepatic manifestations. Conclusions Plasma glial fibrillary acidic protein may serve as a biomarker for distinguishing different subtypes of Wilson disease. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Primary familial brain calcification (PFBC) is an inherited neurodegenerative disorder mainly characterized by progressive calcium deposition bilaterally in the brain, accompanied by various symptoms, such as dystonia, ataxia, parkinsonism, dementia, depression, headaches, and epilepsy. Currently, the etiology of PFBC is largely unknown, and no specific prevention or treatment is available. During the past 10 years, six causative genes (SLC20A2, PDGFRB, PDGFB, XPR1, MYORG, and JAM2) have been identified in PFBC. In this review, considering mechanistic studies of these genes at the cellular level and in animals, we summarize the pathogenesis and potential preventive and therapeutic strategies for PFBC patients. Our systematic analysis suggests a classification for PFBC genetic etiology based on several characteristics, provides a summary of the known composition of brain calcification, and identifies some potential therapeutic targets for PFBC.

Brain calcification is a critical aging-associated pathology and can cause multifaceted neurological symptoms. Cerebral phosphate homeostasis dysregulation, blood-brain barrier defects, and immune dysregulation have been implicated as major pathological processes in familial brain calcification (FBC). Here, we analyzed two brain calcification families and identified calcification co-segregated biallelic variants in the CMPK2 gene that disrupt mitochondrial functions. Transcriptome analysis of peripheral blood mononuclear cells (PBMCs) isolated from these patients showed impaired mitochondria-associated metabolism pathways. In situ hybridization and single-cell RNA sequencing revealed robust Cmpk2 expression in neurons and vascular endothelial cells (vECs), two cell types with high energy expenditure in the brain. The neurons in Cmpk2-knockout (KO) mice have fewer mitochondrial DNA copies, down-regulated mitochondrial proteins, reduced ATP production, and elevated intracellular inorganic phosphate (Pi) level, recapitulating the mitochondrial dysfunction observed in the PBMCs isolated from the FBC patients. Morphologically, the cristae architecture of the Cmpk2-KO murine neurons was also impaired. Notably, calcification developed in a progressive manner in the homozygous Cmpk2-KO mice thalamus region as well as in the Cmpk2-knock-in mice bearing the patient mutation, thus phenocopying the calcification pathology observed in the patients. Together, our study identifies biallelic variants of CMPK2 as novel genetic factors for FBC; and demonstrates how CMPK2 deficiency alters mitochondrial structures and functions, thereby highlighting the mitochondria dysregulation as a critical pathogenic mechanism underlying brain calcification.

Spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominant ataxia globally. No effective treatment is currently available for SCA3. Repetitive Transcranial Magnetic Stimulation (rTMS) is a non-invasive form of brain stimulation, demonstrated to improve symptoms in patients with neurodegenerative cerebellar ataxias. The present study investigated whether treatment with rTMS over the cerebellum for 15 consecutive days improved measures of ataxia in SCA3 patients.A double-blind, prospective, randomized, sham-controlled trial was carried out on 44 SCA3 patients. Participants were randomly assigned to two groups: real or sham stimulation. Each participant underwent 30 minutes of 1Hz rTMS stimulation (a total of 900 pulses) for 15 consecutive days. The primary outcome measure was the score on the International Cooperative Ataxia Rating Scale (ICARS), and secondary outcomes were from the Scale for the Assessment and Rating of Ataxia (SARA) and the Berg Balance Scale (BBS).Nausea was the only adverse effect reported by 2 participants from the sham and real group. After 15 days of treatment, there was a significant improvement in all performance scores in both real and sham stimulation groups. However, compared to the sham group, the improvements were significantly larger in the real group for the ICARS (P = 0.002), SARA (P = 0.001), and BBS (P = 0.001).A 15 days treatment with rTMS over the cerebellum improves the symptoms of ataxia in SCA3 patients. Our results suggest that rTMS is a promising tool for future rehabilitative approaches in SCA3.

Background Aim to identify potential biomarkers to assess therapeutic efficacy for hereditary spastic paraplegias type 5 (SPG5) by investigating the clinical, cerebrospinal fluid (CSF) and magnetic resonance imaging (MRI) features. Methods We performed a cross-sectional study to compare SPG5 patients with age- and sex-matched healthy controls who underwent conventional and quantitative MRI techniques of spinal cord (C1-T9) and brain. SPG5 patients also underwent assessment for clinical status and CSF biomarkers (27-hydroxycholesterol, neurofilament light). We identified a set of markers with standardized effect sizes (|t|> 0.5) to estimate sample sizes for disease progression (disease duration > 14 years vs. ≤ 14 years). Results Seventeen genetically confirmed SPG5 patients (11 men, 6 women; age range, 13–49 years; median disease duration, 14 years) were enrolled. Compared to healthy controls, the total spinal cord area (SCA) of SPG5 patients was reduced particularly at the thoracic levels (cervical levels: 12–27%; thoracic levels 41–60%). Patients did not show significant alterations of brain signal abnormalities or atrophy relative to controls. A total of 10 surrogate markers were selected and a minimum sample size was achieved with the measurement of SCA on T9 (n = 22) much less that what would be required if using clinical disability assessment (n = 124). Conclusions SPG5 patients showed distinct MRI features of spinal cord atrophy without significant brain alterations. Our finding supports the measurements of spinal cord on T9 level as potential endpoint for SPG5 clinical trials. Trial registration ClinicalTrials.gov, NCT04006418. Registered 05 July 2019, https://clinicaltrials.gov/ct2/show/NCT04006418?term=NCT04006418&draw=2&rank=1.

Neurogenetic diseases are neurological conditions with a genetic cause (s). There are thousands of neurogenetic diseases, and most of them are incurable. The development of bioinformatics and elucidation of the mechanism of pathogenesis have allowed the development of gene therapy approaches, which show great potential in treating neurogenetic diseases. Viral vectors delivery, antisense oligonucleotides, gene editing, RNA interference, and burgeoning viroid delivery technique are promising gene therapy strategies, and commendable therapeutic effects in the treatment of neurogenetic diseases have been achieved (Fig. 1). This review highlights a sampling of advances in gene therapies for neurogenetic disorders. Fig. 1 Examples of gene therapy strategies used in the treatment of neurogenetic diseases. The schematic diagram shows different gene therapy approaches used for treating a sampling of neurogenetic disorders, such as ASO therapy, gene editing, gene augmentation, and RNA interference.

Hereditary spastic paraplegia (HSP) refers to a group of neurodegenerative disorders characterized by bilateral weakness, spasticity, and hyperreflexia in the lower limbs. The autosomal dominant HSP (ADHSP) predominantly presents as the pure form, but the clinical profiles and causal genetic variants underlying ADHSP are complex, and many remain unknown. A cohort of 15 Chinese HSP pedigrees (including 35 patients and their 22 relatives) were screened by multiplex ligation-dependent probe amplification (MLPA) or whole-exome sequencing (WES). Neurological assessments were also conducted. The main subtypes of HSP above detected in our cohort were SPG4, SPG3A, and SPG6. Fifteen HSP-inducing mutations were identified, among which six were novel mutations: SPAST c.1277T>C, c.1292G>C, c.1562T>C, and c.1693A>T, NIPA1 c.748A>C, and KIDINS220 c.4448C>G. As expected, the most common presentation of the ADHSP cases was the pure form, manifesting spasticity of lower limbs and hyperreflexia, as well as pyramidal signs. Differing substantially from previous reports for KIDINS220 variants, our study family exhibited autosomal dominant inheritance, and only presented with spastic paraplegia, with no signs of intellectual disability, nystagmus, or obesity. Our work reveals a non-classical spastic paraplegia, intellectual disability, nystagmus, and obesity phenotype for a KIDINS220 mutation, which broadens both the clinical and genetic spectrum for ADHSP. Beyond underscoring the utility of using both MLPA and WES in studies of HSP, our work deepens the scientific understanding of phenotypes for ADHSP and defines new genetic variants to facilitate future diagnoses.

We here report a genome-editing strategy to correct spinal muscular atrophy (SMA). Rather than directly targeting the pathogenic exonic mutations, our strategy employed Cas9 and guide-sgRNA for the targeted disruption of intronic splicing-regulatory elements. We disrupted intronic splicing silencers (ISSs, including ISS-N1 and ISS + 100) of survival motor neuron (SMN) 2, a key modifier gene of SMA, to enhance exon 7 inclusion and full-length SMN expression in SMA iPSCs. Survival of splicing-corrected iPSC-derived motor neurons was rescued with SMN restoration. Furthermore, co-injection of Cas9 mRNA from Streptococcus pyogenes (SpCas9) or Cas9 from Staphylococcus aureus (SaCas9) alongside their corresponding sgRNAs targeting ISS-N1 into zygotes rescued 56% and 100% of severe SMA transgenic mice (Smn−/−, SMN2tg/−). The median survival of the resulting mice was extended to >400 days. Collectively, our study provides proof-of-principle for a new strategy to therapeutically intervene in SMA and other RNA-splicing-related diseases.

Hereditary spastic paraplegias refer to a heterogeneous group of neurodegenerative disorders resulting from degeneration of the corticospinal tract. Clinical characterization of patients with hereditary spastic paraplegias represents progressive spasticity, exaggerated reflexes and muscular weakness. Here, to expand on the increasingly broad pools of previously unknown hereditary spastic paraplegia causative genes and subtypes, we performed whole exome sequencing for six affected and two unaffected individuals from two unrelated Chinese families with an autosomal dominant hereditary spastic paraplegia and lacking mutations in known hereditary spastic paraplegia implicated genes. The exome sequencing revealed two stop-gain mutations, c.247_248insGTGAATTC (p.I83Sfs*11) and c.526G>T (p.E176*), in the ubiquitin-associated protein 1 (UBAP1) gene, which co-segregated with the spastic paraplegia. We also identified two UBAP1 frameshift mutations, c.324_325delCA (p.H108Qfs*10) and c.425_426delAG (p.K143Sfs*15), in two unrelated families from an additional 38 Chinese pedigrees with autosomal dominant hereditary spastic paraplegias and lacking mutations in known causative genes. The primary disease presentation was a pure lower limb predominant spastic paraplegia. In vivo downregulation of Ubap1 in zebrafish causes abnormal organismal morphology, inhibited motor neuron outgrowth, decreased mobility, and shorter lifespan. UBAP1 is incorporated into endosomal sorting complexes required for transport complex I and binds ubiquitin to function in endosome sorting. Patient-derived truncated form(s) of UBAP1 cause aberrant endosome clustering, pronounced endosome enlargement, and cytoplasmic accumulation of ubiquitinated proteins in HeLa cells and wild-type mouse cortical neuron cultures. Biochemical and immunocytochemical experiments in cultured cortical neurons derived from transgenic Ubap1flox mice confirmed that disruption of UBAP1 leads to dysregulation of both early endosome processing and ubiquitinated protein sorting. Strikingly, deletion of Ubap1 promotes neurodegeneration, potentially mediated by apoptosis. Our study provides genetic and biochemical evidence that mutations in UBAP1 can cause pure autosomal dominant spastic paraplegia.

Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder with four causative genes (SLC20A2, PDGFRB, PDGFB, and XPR1) that have been identified. Here, we aim to describe the mutational spectrum of four causative genes in a series of 226 unrelated Chinese PFBC patients. Mutations in four causative genes were detected in 16.8% (38/226) of PFBC patients. SLC20A2 mutations accounted for 14.2% (32/226) of all patients. Mutations in the other three genes were relatively rare, accounting for 0.9% (2/226) of all patients, respectively. Clinically, 44.8% of genetically confirmed patients (probands and relatives) were considered symptomatic. The most frequent symptoms were chronic headache, followed by movement disorders and vertigo. Moreover, the total calcification score was significantly higher in the symptomatic group compared to the asymptomatic group. Functionally, we observed impaired phosphate transport induced by seven novel missense mutations in SLC20A2 and two novel mutations in XPR1. The mutation p.D164Y in XPR1 might result in low protein expression through an enhanced proteasome pathway. In conclusion, our study further confirms that mutations in SLC20A2 are the major cause of PFBC and provides additional evidence for the crucial roles of phosphate transport impairment in the pathogenies of PFBC.

Background: Hereditary spastic paraplegia (HSP) caused by mutations in ALDH18A1 have been reported as spastic paraplegia 9 (SPG9), with autosomal dominant and autosomal recessive transmission (SPG9A and SPG9B). SPG9 is rare and has shown phenotypic and genotypic heterogeneity in previous reports.Methods: This study screened ALDH18A1 mutations in autosomal recessive HSP patients using combined whole exome sequencing and RNA splicing analysis. We conducted in silico investigations, co-segregation analysis, and ELISA-based analysis of P5CS (Δ1-pyrroline-5-carboxylate synthetase; encoded by ALDH18A1) concentration to validate the pathogenicity of the detected ALDH18A1 variants. All previously reported bi-allelic ALDH18A1 mutations and cases were reviewed to summarize the genetic and clinical features of ALDH18A1-related HSP.Results: A novel missense mutation c.880T>C, p.S294P and an intronic splicing mutation c.-28-13A>G were both detected in ALDH18A1 in an autosomal recessive family presenting with a complicated form HSP. ELISA assays revealed significantly decreased P5CS concentration in the proband's plasma compared with that in the healthy controls. Moreover, review of previously reported recessive cases showed that SPG9B patients in our cohort presented with milder symptoms, i.e., later age at onset and without cognitive impairment.Conclusion: The present study expands the genetic and clinical spectrum of SPG9B caused by ALDH18A1 mutation. Our work defines new genetic variants to facilitate future diagnoses, in addition to demonstrating the highly informative value of splicing mutation prediction in the characterization of disease-related intronic variants.

Background: Hereditary spastic paraplegia (HSP) caused by mutations in ALDH18A1 have been reported as spastic paraplegia 9 (SPG9), with autosomal dominant and autosomal recessive transmission (SPG9A and SPG9B). SPG9 is rare and has shown phenotypic and genotypic heterogeneity in previous reports. Methods: This study screened ALDH18A1 mutations in autosomal recessive HSP patients using combined whole exome sequencing and RNA splicing analysis. We conducted in silico investigations, co-segregation analysis, and ELISA-based analysis of P5CS (Δ1-pyrroline-5-carboxylate synthetase; encoded by ALDH18A1) concentration to validate the pathogenicity of the detected ALDH18A1 variants. All previously reported bi-allelic ALDH18A1 mutations and cases were reviewed to summarize the genetic and clinical features of ALDH18A1-related HSP. Results: A novel missense mutation c.880T>C, p.S294P and an intronic splicing mutation c.-28-13A>G were both detected in ALDH18A1 in an autosomal recessive family presenting with a complicated form HSP. ELISA assays revealed significantly decreased P5CS concentration in the proband's plasma compared with that in the healthy controls. Moreover, review of previously reported recessive cases showed that SPG9B patients in our cohort presented with milder symptoms, i.e., later age at onset and without cognitive impairment. Conclusion: The present study expands the genetic and clinical spectrum of SPG9B caused by ALDH18A1 mutation. Our work defines new genetic variants to facilitate future diagnoses, in addition to demonstrating the highly informative value of splicing mutation prediction in the characterization of disease-related intronic variants.

Background: Hereditary spastic paraplegias type 5 (SPG5) is an inherited neurodegenerative disease with 27-hydroxycholesterol abnormal accumulation. Imaging and pathologic manifestations remain poorly understood due to the rare incidence. This study reveals the MRI features of SPG5, and aims to investigate a promising imaging diagnostic biomarker for SPG5.Methods: We prospectively recruited SPG5 patients and matched healthy controls from Neurogenetic Diseases Centers of Fujian province in China, clinical and MRI data of whom were collected. Abnormalities of spinal cord and brain were characterized and quantified by conventional and quantitative MRI. Comparisons were conducted between MRI and cerebrospinal fluid (CSF) bioindicators.Results: Seventeen SPG5 patients were enrolled (11 men, 6 women; age range, 13–49 years; median disease duration, 14 years). For the first time, T2 hyperintensities with “+” form (cross sign) in atrophic spinal cord was found among all SPG5 patients. To grade severity of this sign, we set up a scoring scale (cross-sign scores) in cervical spinal cords. Unexpectedly, total cross-sign scores showed a strong positive correlation with disability scale scores (r = 0.687, P = 0.002) and disease duration (r = 0.520, P = 0.032). Although total spinal cord area was reduced (cervical levels: 12-27%; thoracic levels 41-60%), no correlation was found between spinal cord atrophy and disease severity. In CSF, a positive correlation was identified between 27-hydroxycholesterol and neurofilament light (r = 0.468, P = 0.049), although 27-hydroxycholesterol and neurofilament light were unrelated to disease severity.Conclusion: Cross sign of spinal cord was established as a potentially diagnostic biomarker linked to SPG5 that can guide genetic testing and interpret genetic results. Moreover, cross-sign scoring scale is more sensitive than spinal cord area and CSF markers for monitoring SPG5 progress in our research.

BackgroundPostural instability is one of the most disabling features of spinocerebellar ataxias type 3 (SCA3) and often leads to falls that reduce mobility and functional capacity. This study aimed to quantitatively analyse static and dynamic balance and proprioception function on postural control in patients with SCA3 using the Pro-kin system and optimise rehabilitation programmes for them.MethodsEight-one clinically diagnosed SCA3 patients (38 women, 43 men; aged 39.00 ± 9.66) and 62 healthy controls were studied and evaluated using the Pro-kin system (PK254P, Tecnobody S.r.l, Dalmine, Italy). The measurements included (1) a static balance test in two visual feedback conditions: eyes open (EO) and eyes closed (EC); (2) a dynamic balance test measuring limits of stability (LOS); and (3) a proprioception function test to obtain proprioceptive measurements on a multiaxial balance evaluator for both right and left lower limbs.ResultsCompared to controls, SCA3 patients showed significantly higher values of all static balance outcome variables with eyes open and eyes closed, implying postural instability. SCA3 patients showed significantly higher values in the standard deviation of body sway along the medio-lateral (ML) axis and in the velocity of body sway along the anterior-posterior (AP) axis. The overall scores and the scores for all eight LOS components were significantly lower in the SCA3 patients than in the controls. The mean values of AP index (API), ML index (MLI), Stability index (SI) and average trace error (ATE) were significantly greater in SCA3 patients compared to HC subjects, while API showed a trend toward higher values.ConclusionsSCA3 patients have a significant postural control disorder, and are likely to fall on the AP plane and prefer performing postural adjustments in the ML direction; a decreased proprioception function in the knee and ankle is also evident. Visual cues and proprioception should be emphasized in balance rehabilitation training. Attention should also be paid to improve muscle strength and range of motion.Trial registrationThe Chinese clinical test registration center. ChiCTR1800020133. Registered 15 december 2018 - Retrospectively registered, http://www.chictr.org.cn/showprojen.aspx?proj=33950

The original version of this article unfortunately contained mistakes in the affiliation section.

Background: Hereditary spastic paraplegia type 5 (SPG5) is an ultra-rare neurogenetic axon-degenerative disease. The absence of treatment to prevent disease progression represents a major unmet clinical need. With a greater understanding of the pathophysiological basis of SPG5, opportunities have emerged for providing a targeted mechanistic therapy. The aims of this preliminary study were to investigate the efficacy of a PCSK9 inhibitor, Evolocumab, as a cholesterol-lowering therapy for reducing the accumulation of neurotoxic oxysterols and to evaluate the effects on axonal degeneration. Methods: This was as an open-label, evaluator-blind, single-center pilot study in which 23 SPG5 patients each received a single subcutaneous injections of 420 mg Evolocumab. Clinical data, CSF and blood were collected for analysis at enrollment and subsequent day 30. Induced pluripotent stem cells (iPSCs) were generated from the fibroblasts of a SPG5 patient to assess the mechanism of PCSK9 inhibitor’s effect on treatment. Findings: This trial is the largest sample-size prospective study among any treatment trial for SPG5. In this relatively homogeneous group of SPG5 patients (96% carried the same known nonsense mutation c.334 C>T; the median age was 34 years; disease duration was 16 years), we found that PCSK9 inhibitor significantly lowered levels of the toxic metabolite 27-hydroxycholesterol (27-OHC) in plasma (median (IQR), 589(487-644) vs. 396(348-468) ng/ml , P < 0.001). CSF 27-OHC decreased in 12 (71%) patients with a median reduction by 11% from the median 10 ng/ml before treatment to 8.3 ng/ml after treatment (P = 0.012). Most importantly, axonal degeneration, assessed by using neurofilament light (NFL) as a quantitative biomarker, receded at 30 days after single-dose Evolocumab treatment. Additionally, using iPSC-derived motor neurons, this study also showed that PCSK9 inhibitor had anti-apoptosis activity in SPG5 patients. Interpretation: The potential biological activity of cholesterol modulation for SPG5 patients, that is, alleviation of damage to axons from the effects of neurotoxic oxysterol, as well as the absence of adverse effects associated with the use of PCSK9 inhibitor therapy documented here deserves, in fact urges, full evaluation by well-designed long-term clinical trials. Trial Registration: This study is registered with ClinicalTrials.gov, number: NCT01892345. Funding Statement: This work has been supported by grants U1905210 (W.-J.C.), 81771230(W.-J.C.) and 81801130 (X.L.) from the National Natural Science Foundation of China, Joint Funds for the Innovation of Science and Technology of Fujian Province (2017Y9094) (W.-J.C.) and (2018Y9082) (N.W.), the Natural Science Foundation of Fujian Province (2019J02010) (W.-J.C.) and (2019J05076) (X.L.), the Key Clinical Specialty Discipline Construction Program of Fujian (N.W.). Declaration of Interests: All authors report no conflict of interest. Fujian medical university school of public health have received consultant fees as statistician to perform the data analysis. Ethics Approval Statement: The study protocol and informed consent procedures were approved by the institutional review board. Written informed consent was provided by the patients and their health care proxies.

IntroductionHereditary spastic paraplegias (HSPs) are uncommon but not rare neurodegenerative diseases. More than 100 pathogenic genes and loci related to spastic paraplegia symptoms have been reported. HSPs have the same core clinical features, including progressive spasticity in the lower limbs, though HSPs are heterogeneous (eg, clinical signs, MRI features, gene mutation). The age of onset varies greatly, from infant to adulthood. In addition, the slow and variable rates of disease progression in patients with HSP represent a substantial challenge for informative assessment of therapeutic efficacy. To address this, we are undertaking a prospective cohort study to investigate genetic–clinical characteristics, find surrogates for monitoring disease progress and identify clinical readouts for treatment.Methods and analysisIn this case-control cohort study, we will enrol 200 patients with HSP and 200 healthy individuals in parallel. Participants will be continuously assessed for 3 years at 12-month intervals. Six aspects, including clinical signs, genetic spectrum, cognitive competence, MRI features, potential biochemical indicators and nerve electrophysiological factors, will be assessed in detail. This study will observe clinical manifestations and disease severity based on different molecular mechanisms, including oxidative stress, cholesterol metabolism and microtubule dynamics, all of which have been proposed as potential treatment targets or modalities. The analysis will also assess disease progression in different types of HSPs and cellular pathways with a longitudinal study using t tests and χ2 tests.Ethics and disseminationThe study was granted ethics committee approval by the first affiliated hospital of Fujian Medical University (MRCTA, ECFAH of FMU (2019)194) in 2019. Findings will be disseminated via presentations and peer-reviewed publications. Dissemination will target different audiences, including national stakeholders, researchers from different disciplines and the general public.Trial registration numberNCT04006418.

Summary: Background: Facioscapulohumeral muscular dystrophy type 1 (FSHD1) is a rare disease, which is often underdiagnosed due to its heterogeneous presentations and complex molecular genetic basis, leading to a lack of population-based epidemiology data, especially of prevalence and disease progression. Methods: Fujian Neuromedical Centre (FNMC) is a diagnosis centre for clinical-genetic FSHD in China, and the only one employing pulsed-field gel electrophoresis (PFGE)-based Southern blotting for all FSHD1 genetic tests. Three sources distributed across all six spatial zones in China, were used to obtain information regarding FSHD1 events, namely, FNMC, Genetic and Myopathy Group (branches of the Neurology Society of the Chinese Medical Association), and “FSHD-China” (an organization supported by FSHD patients). During 2001-2020, all genetically-confirmed FSHD1 from China were registered in FNMC. Follow-up was conducted in the 20-year period to obtain data on disease progression, which was mainly described in terms of independent ambulation loss. Findings: Of the 1,744 FSHD1 genetic tests (total test number 1,802) included in the analysis, 997 (57.2%) patients from 620 families were diagnosed with FSHD1. The estimated prevalence of genetically-confirmed FSHD1 in China is 0.75 per million (95% confidence interval [CI], 0.70-0.79) during 2001-2020, with 0.78 (95% CI, 0.72-0.85) in males and 0.71 (95% CI, 0.65-0.78) in females. The estimated prevalence increased from 0.22 (95% CI, 0.19-0.26) per million in 2001-2015 to 0.53 (95% CI, 0.49-0.57) per million in 2016-2020 (p < 0.001). The prevalence in Fujian province was 7.10 per million, 4.66 per million, and 2.44 per million, during 2001-2020, 2001-2015, and 2016-2020, respectively. Among the 861 symptomatic plus asymptomatic patients of the total 997 patients, the median onset age at first-ever muscle weakness was 16 years of age (range 1-81); the median number of contracted D4Z4 repeats was 5 units (range 1-9); the median 4qA-allele-specific methylation level was 41% (range 14%-69%). Of the 977 symptomatic patients followed-up during 2001-2020, 117 patients (12.0%) lost independent ambulation. The expected duration from onset of first-ever muscle weakness to onset of independent ambulation loss was 40 years. The group with loss of independent ambulation had a smaller number of contracted D4Z4 repeats (p < 0.001) and had an earlier onset age of first-ever muscle weakness (p < 0.001) compared to the group without loss of independent ambulation. Interpretation: Our research captures the largest genetically-confirmed FSHD1 population worldwide, to calculate its prevalence of 0.75 per million in China from 2001 to 2020. Approximately 12.0% of symptomatic plus asymptomatic patients of FSHD1 will lose independent ambulation in 40 years from onset of first-ever muscle weakness. Funding: This work has been supported by the grants (U2005201, 81870902, N.W.) and (81974193, 81671237, Z.Q.W.) from the National Natural Science Foundation of China; Joint Funds for the Innovation of Science and Technology of Fujian Province (2018Y9082) (N.W.), and the Key Clinical Specialty Discipline Construction Program of Fujian (N.W.).

Primary familial brain calcification (PFBC) is a neuropsychiatric disorder characterized by bilateral cerebral calcification with diverse neurologic or psychiatric symptoms. Recently, XPR1 variation has accounted for PFBC as another new causative gene. However, little is known about the distribution and basic function of XPR1 and its interaction with the other three pathogenic genes for PFBC (SLC20A2, PDGFRB and PDGFB). The aim of this study was to further clarify the role of XPR1 in PFBC brain pathology. As a result, gene expression profiles showed that XPR1 mRNA was widely expressed throughout the mouse brain. Cerebellum and striatum, most commonly affected in PFBC, contained a higher level of XPR1 protein than other brain regions. Additionally, XPR1 deficiency seriously affected Pi efflux and XPR1 mutations seemed to have an effect through haploinsufficiency mechanism. The immunoprecipitation and immunohistochemical studies demonstrated that XPR1 could interact with PDGFRB and might form a complex on the cell membrane. These results suggested that XPR1 played a fundamental role in the maintenance of cellular phosphate balance in the brain. This provided us with a novel perspective on understanding the pathophysiology of PFBC. The expression networks and interaction with the known pathogenic genes could shed new light on additional candidate genes for PFBC.

The development of clinical trials for Duchenne muscular dystrophy (DMD) in China faces many challenges due to limited information about epidemiological data, natural history and clinical management. To provide these detailed data, we developed a comprehensive database based on registered DMD patients from South China and analysed their clinical and mutational characteristics. The database included DMD registrants confirmed by clinical presentation, family history, genetic detection, prognostic outcome, and/or muscle biopsy. Clinical data were collected by a registry form. Mutations of dystrophin were detected by multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. Currently, 132 DMD patients from 128 families in South China have been registered, and 91.7% of them were below 10 years old. In mutational detection, large deletions were the most frequent type (57.8%), followed by small deletion/insertion mutations (14.1%), nonsense mutations (13.3%), large duplications (10.9%), and splice site mutations (3.1%). Clinical analysis revealed that most patients reported initial symptoms between 1 and 3 years of age, but the diagnostic age was more frequently between 6 and 8 years. 81.4% of patients were ambulatory. Baseline cardiac assessments at diagnosis were conducted in 39.4% and 29.5% of patients by echocardiograms and electrocardiograms, respectively. Only 22.7% of registrants performed baseline respiratory assessments. A small numbers of patients (20.5%) were treated with glucocorticoids. 13.3% of patients were eligible for stop codon read-through therapy, and 48.4% of patients would potentially benefit from exon skipping. The top five exon skips applicable to the largest group of registrants were skipping of exons 51 (14.8% of total mutations), 53 (12.5%), 45 (7.0%), 55 (4.7%), and 44 (3.9%). In conclusion, our database provided information on the natural history, diagnosis and management status of DMD in South China, as well as potential molecular therapies suitable for these patients. This comprehensive database will promote future experimental therapies in China.

Four causative genes, including solute carrier family 20 member 2 (SLC20A2), platelet-derived growth factor receptor b (PDGFRB), platelet-derived growth factor b (PDGFB)and xenotropic and polytropic retrovirus receptor 1 (XPR1), have been identified to cause primary familial brain calcification (PFBC). However, PDGFRB mutations seem to be quite rare and no PDGFRB mutations have been reported in Chinese PFBC patients. A total of 146 PFBC patients including 12 families and 134 sporadic patients were recruited in this study. All of them were previously tested negative for the SLC20A2. Mutational analyses of the entire exons and exon-intron boundaries of PDGFRB were carried out by direct gene sequencing. In silico analyses of the identified variants were conducted using Mutation Taster, PolyPhen-2 and Sorts Intolerant From Tolerant. Two heterozygous variants, c.3G>A and c.2209G>A, of the PDGFRB gene were revealed in two PFBC families, respectively. These two variants were not observed in 200 healthy controls. The variant c.3G>A was located in exon 2 and affected the initiation codon of the PDGFRB gene. The variant c.2209G>A resulted in amino-acid substitutions of aspartic acid to asparagine at position 737. Both of these two variants co-segregated with the disease phenotype (variant carriers in Family 1: I1, II2 and II3; variant carriers in Family 2: I2 and II8), suggesting a pathogenic impact of these variants. The prevalence of PDGFRB mutations in Chinese PFBC patients seems to be quite low, indicating that PDGFRB is not a major causative gene of PFBC in Chinese population.

// Xiang Lin 1, * , Jin-Jing Li 1, * , Wen-Jing Qian 2, * , Qi-Jie Zhang 1 , Zhong-Feng Wang 2 , Ying-Qian Lu 1 , En-Lin Dong 1 , Jin He 1 , Ning Wang 1 , Li-Xiang Ma 3 and Wan-Jin Chen 1, 4 1 Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China 2 Institutes of Brain Science, Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China 3 Department of Anatomy, Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China 4 Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China * These authors have contributed equally to this work Correspondence to: Wan-Jin Chen, email: wanjinchen75@fjmu.edu.cn Li-Xiang Ma, email: lxma@fudan.edu.cn Keywords: spinal muscular atrophy (SMA), induced pluripotent stem cells (iPSCs) derived enriched motor neurons (MNs), survival motor neuron (SMN) protein, neurite outgrowth, neuronal activity Received: August 20, 2016 Accepted: December 27, 2016 Published: January 31, 2017 ABSTRACT Spinal muscular atrophy (SMA) is a devastating motor neuron disease caused by mutations of the survival motor neuron 1 ( SMN1 ) gene. SMN2 , a paralogous gene to SMN1 , can partially compensate for the loss of SMN1 . On the basis of age at onset, highest motor function and SMN2 copy numbers, childhood-onset SMA can be divided into three types (SMA I-III). An inverse correlation was observed between SMN2 copies and the differential phenotypes of SMA. Interestingly, this correlation is not always absolute. Using SMA induced pluripotent stem cells (iPSCs), we found that the SMN was significantly decreased in both SMA III and SMA I iPSCs derived postmitotic motor neurons (pMNs) and γ-aminobutyric acid (GABA) neurons. Moreover, the significant differences of SMN expression level between SMA III (3 copies of SMN2 ) and SMA I (2 copies of SMN2 ) were observed only in pMNs culture, but not in GABA neurons or iPSCs. From these findings, we further discovered that the neurite outgrowth was suppressed in both SMA III and SMA I derived MNs. Meanwhile, the significant difference of neurite outgrowth between SMA III and SMA I group was also found in long-term cultures. However, significant hyperexcitability was showed only in SMA I derived mature MNs, but not in SMA III group. Above all, we propose that SMN protein is a major factor of phenotypic modifier. Our data may provide a new insight into recognition for differential phenotypes of SMA disease.

Background Until recently, primary familial brain calcification (PFBC) has been determined by four genes, SLC20A2 , PDGFRB , PDGFB and XPR1 . No studies have been carried out to analyze the gene mutation of PDGFB in Chinese population. Objective To screen mutations of PDGFB gene in a large cohort of Chinese PFBC patients with no SLC20A2 mutations. Methods We recruited 192 PFBC patients, including 21 index cases and 171 sporadic cases, in our study. Peripheral venous blood samples of all included participants were collected for genomic DNA extraction. The coding sequence of PDGFB was amplified by polymerase chain reaction (PCR) followed by direct sequencing. The potential effects of the identified variants on protein function were assessed by bioinformatics analysis. Results Three missense variants (c.35G > T, c.232C > T, and c.610C > A) and one nonsense variant (c.220G > T) of PDGFB were identified in five sporadic PFBC patients. The variant c.35G > T was found in 2 healthy controls from the same ethnic background, whereas c.220G > T, c.232C > T and c.610C > A were absent from 500 controls. c.220G > T (p.E74*) produced a stop codon in the place of the glutamic acid residue number 74. c.232C > T (p.R78C) occurred at highly conserved regions and were predicted as damaging by at least two computational predictive programs, suggesting that this variant was likely to have a causal role in PFBC. Although variant c.610C > A (p.P204T) also occurred at a highly conserved region, it was predicted to be most likely benign by two computational predictive programs, suggesting an uncertain role of this variant on PFBC. Conclusions The present study identified one likely pathogenic variant (p.E74*) and two variants of uncertain significance (p.R78C and p.P204T) in PDGFB . Further studies of PDGF-B functional expression for these variants are still required to confirm the pathogenic effect.

Charcot-Marie-Tooth disease type 2 (CMT2) is a clinically and genetically heterogeneous inherited neuropathy. Although new causative and disease-associated genes have been identified for CMT2 in recent years, molecular diagnoses are still lacking for a majority of patients. We here studied a cohort of 35 CMT2 patients of Chinese descent, using whole exome sequencing to investigate gene mutations and then explored relationships among genotypes, clinical features, and mitochondrial DNA levels in blood as assessed by droplet digital PCR. We identified pathogenic variants in 57% of CMT2 patients. The most common genetic causes in the cohort were MFN2 mutations. Two patients with typical CMT phenotype and neuromyotonia were detected to harbor compound heterozygous variations in the HINT1 gene. In conclusion, our work supports that the molecular diagnostic rate of CMT2 patients can be increased via whole exome sequencing, and our data suggest that assessment of possible HINT1 mutations should be undertaken for CMT2 patients with neuromyotonia.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a wide range of survival times. We aimed to explore prognostic factors related to short survival based on clinical features and plasma metabolic signatures using surface-enhanced Raman spectroscopy (SERS). One hundred and thirty-eight sporadic ALS cases were enrolled serially, including 62 for the short-duration group (≤3 years) and 76 for the long-duration group (3 years). Multivariate analysis showed that an older age of onset (60 years; odds ratio [OR] = 3.98, 95% CI: 1.09-14.53), lower body mass index (BMI) (18.5; OR = 6.80, 95% CI: 1.36-33.92), and lower ALSFRS-R score (35; OR = 6.03, 95% CI: 1.42-25.63) were associated with higher odds of tracheotomy or death, while a higher uric acid (UA) level showed a protective effect (356.36 μmol/L; OR = 0.19, 95% CI: 0.05-0.73). SERS analysis showed significant differences between the two groups, and pathway analysis highlighted five main metabolic pathways, including metabolisms of glutathione, pyrimidine, phenylalanine, galactose, and phenylalanine-tyrosine-tryptophan biosynthesis. In conclusion, age of onset, BMI, ALSFRS-R score and UA, together with dysregulation of glucose, amino acid, nucleic acid, and antioxidant metabolism contributed to disease progression, and are therefore potential therapeutic targets for ALS.

Introduction X-linked adrenoleukodystrophy (ALD) and Zellweger spectrum disorder (ZSD) are peroxisomal diseases characterized by accumulation of very long chain fatty acids (VLCFA) in plasma and tissues. Considering the wide variability of manifestation, patients of ALD and atypical ZSD are easily misdiagnosed as hereditary spastic paraplegia (HSP) on their clinical grounds. Here, we aimed to determine the frequency of peroxisome diseases and compare their phenotypic spectra with HSP. Methods We first applied targeted sequencing in 120 pedigrees with spastic paraplegia, and subsequently confirmed 74 HSP families. We then performed whole exome sequencing for the probands of the 46 remaining pedigrees lacking known HSP-causal genes. Detailed clinical, radiological features, and VLCFA analyses are presented. Results Seven ALD pedigrees with ABCD1 mutations and one ZSD family harboring bi-allelic mutations of PEX16 were identified. Clinically, in addition to spastic paraplegia, four ALD probands presented adrenocortical insufficiency, and the ZSD proband and her affected sister both developed thyroid problems. VLCFA analysis showed that ratios of C24/C22 and C26/C22 were specifically increased in ALD probands. Moreover, three ALD probands and the ZSD proband had abnormalities in brain or spinal imaging. Conclusions Our study reports the first ZSD case in China that manifested spastic paraplegia, and emphasized the finding that peroxisomal diseases comprise a significant proportion (8/120) of spastic paraplegia entities. These findings extend our current understanding of the ALD and ZSD diseases.

Purpose Tuberous sclerosis complex (TSC) is characterized by the development of hamartomas in multiple organ systems. This study attempted to screen mutations and to investigate the mutation distribution and related phenotypes including epilepsy of Chinese TSC patients. Methods We performed the genotypic analysis of TSC1 and TSC2 genes in 77 unrelated Chinese TSC patients using direct Sanger sequencing and Multiplex ligation-dependent probe amplification (MLPA). Results Mutations were identified in a total of 63 (81.8%) cases, including 18 TSC1 mutations (8 nonsense mutations, 6 frameshift, 1 in-frame shift, 1 missense and 2 splice-site) and 45 TSC2 mutations (13 missense, 3 nonsense, 6 splicing, 6 in-frame shift,12 frameshift mutations and 5 large deletions). Large deletions were presented exclusively in TSC2 gene, accounting for 7.9% of all mutations in this study. Fourteen novel mutations were identified in this study. Conclusions Epilepsy occurs in approximately 75.3% (58/77) of patients. Hypomelanotic macules occurred significantly more often in patients with TSC2 mutations and cases with TSC1/TSC2 mutations had a significantly higher frequency of cortical nodule than patients with no mutations identified. Overall, our data expands the spectrum of mutations associated with the TSC loci and will be of value to the genetic counseling in patients with the disease.

Intermediate Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of inherited neuropathies characterized by progressive muscle weakness and atrophy of the distal extremities, distal sensory loss. There were still a large proportion of causative genes for intermediate CMT failed to be identified. Here, using whole-exome sequencing technique, we identified two novel missense mutations in ATP1A1 gene, c.620C>T (p.S207F) and c.2629G>A (p.G877S), in two Chinese CMT families. Further functional analysis revealed that these mutations led to the loss function of the ATP1A1 protein. The two mutations did not affect the levels of messenger RNA but possessed a damaging effect on ATP1A1 protein expression and they downregulated the protein levels of ATP1A1 by promoting its proteasome degradation. Taken together, we confirmed ATP1A1 as a novel causative gene for intermediate CMT.

Primary familial brain calcification (PFBC) is a rare neurological disorder. Mutations in five genes (SLC20A2, PDGFRB, PDGFB, XPR1, and MYORG) have been linked to PFBC. Here, we used SYBR green-based real-time quantitative polymerase chain reaction (PCR) assay and denaturing high-performance liquid chromatography analysis to detect copy number variants (CNVs) in 20 unrelated patients with PFBC, negatively sequenced for the five known genes. We identified three deletions in SLC20A2, including a large de novo full gene deletion and two exonic deletions confined to exon 2 and exon 6, respectively. Subsequent linked-read whole-genome sequencing of the patient with the large deletion showed a 1.7 Mb heterozygous deletion which removed the entire coding regions of SLC20A2 as well as 21 other genes. In the family with a deletion of exon 6, a missense variant of uncertain significance (SLC20A2: p.E267Q) also co-segregated with the disease. Functional assay showed the deletion could result in significantly impaired phosphate transport, whereas the p.E267Q variant did not. Our results confirm that deletion in SLC20A2 is a causal mechanism for PFBC and highlight the importance of functional study for classifying a rare missense variant as (likely) pathogenic.

In this paper, we have presented a quantum theory to study one-dimensional photonic crystals, and give the quantum transform matrix and quantum transmissivity. We calculate the quantum transmissivity with defect layer, which include absorbing medium and active medium, and obtain some valuable results. The quantum approach can be used to study two-dimensional and three-dimensional photonic crystals.

The human iPS cell line, hiPS-SPG76 (FJMUi001-A), derived from skin fibroblasts from a 42-year-old male hereditary spastic paraplegia patient carrying compound heterozygous p.P498L (c.1493C > T) and p.R618W (c.1852C > T) mutations in the CAPN1 gene, was generated by non-integrative reprogramming vectors encoding OCT3/4, SOX2, KLF4, and c-MYC. The established hiPS-SPG76 was free of genomically integrated reprogramming genes, had a normal karyotype, expressed pluripotency markers, and had capacity to form three germ layers in vitro and in vivo. This generated hiPS cell line offers a useful resource to study the pathogenesis of SPG76.

Autosomal recessive optic neuropathies (IONs) are extremely rare disorders affecting retinal ganglion cells and the nervous system. RTN4IP1 has recently been identified as the third known gene associated with the autosomal recessive ION optic atrophy 10 (OPA10). Patients with RTN4IP1 mutations show early-onset optic neuropathy that can be followed by additional neurological symptoms such as seizures, ataxia, mental retardation, or even severe encephalopathy. Here, we report two siblings from a Chinese family who presented with early-onset optic neuropathy, epilepsy, and mild intellectual disability. Using whole exome sequencing combined with Sanger sequencing, we identified novel compound heterozygous RTN4IP1 mutations (c.646G > A, p.G216R and c.1162C > T, p.R388X) which both co-segregated with the disease phenotype and were predicted to be disease-causing by prediction software. An in vitro functional study in urine cells obtained from one of the patients revealed low expression of the RTN4IP1 protein. Our results identify novel compound heterozygous mutations in RTN4IP1 which are associated with OPA10, highlighting the frequency of RTN4IP1 mutations in human autosomal recessive IONs. To our knowledge, this is the first report of RTN4IP1 carriers from China.

Introduction The pathophysiologic mechanism of paroxysmal kinesigenic dyskinesia (PKD) is largely unclear. Basal ganglia-thalamo-cortical circuit involvement is thought to underlie PKD pathophysiology. However, microstructural alternations in the motor circuit of PKD require further elucidation. Methods Diffusion tensor imaging and high-resolution T1-weighted imaging were performed on 30 PKD patients (15 PRRT2 carriers, 15 PRRT2 non-carriers) and 15 matched healthy controls. Tract-based spatial statistics were conducted on diffusion indices to examine microstructural integrity of white matter. Voxel-based morphometry analysis was used to examine volumetric changes of gray matter. Multiple regression was employed to test the contribution of demography, disease duration, and PRRT2 status to pathological changes in brain structure. Results Six (including two novel) PRRT2 mutations were identified in PKD patients who exhibited significantly reduced mean diffusivity mainly along the left corticospinal tract, and reduced gray matter volume in pre-supplementary motor area (preSMA) and right opercular part of inferior frontal gyrus (IFGoperc), compared to healthy controls. Both gray matter volume reductions in preSMA and diffusion indices of abnormal white matter negatively correlated with disease duration. Genotype-phenotype analysis revealed that PRRT2 mutation carriers had earlier onset age, longer attacks, and a larger proportion of bilateral symptoms than non-carriers. Conclusions We observed that PRRT2 mutations were associated with disease severity, while neuroanatomical abnormality was associated with disease duration in patients with PKD. Aberrant microstructural changes in preSMA and IFG areas, independent of mutation status, point to dysregulated motor inhibition in patients and provide new insights into neurobiological mechanisms underlying motor symptoms of PKD.

Demyelinating Charcot-Marie-Tooth disease (CMT) is the most common subtype of CMT. It is caused mainly by 17p11.2 heterozygous duplication, but also by mutations in more than 20 genes which affect development and function of Schwann cells. To investigate the profile of genes mutated and clinical features in demyelinating CMT of Chinese descent, we collected a cohort of 44 demyelinating CMT patients and screened them using multiplex ligation-dependent probe amplification (MLPA) and targeted next-generation sequencing (NGS) technology. The MLPA technology revealed that 77.3% demyelinating CMT patients harbored 17p11.2 heterozygous duplication and 6.8% patients harbored heterozygous deletion of exon 6 of MPZ gene, that was further confirmed a novel c.674_675insA mutation in MPZ gene. In the patients with 17p12 heterozygous duplication, 3 sets of independent families were discordant for the CMT phenotype within the same family. The targeted NGS technology revealed that 6 candidate mutations including 1 previously reported mutation (GDAP1: c.571C>T) and 5 novel mutations (SBF2: c.415T>C, c.619G>T, c.1258A>G; GDAP1: c.589delC; PMP22: c.318delT) were found. In conclusion, combined MLPA technique with targeted NGS, the demyelinating CMT genetic diagnostic success rate was increased.

Spinocerebellar ataxia type 3 (SCA3), the most common subtype of SCA worldwide, is caused by mutation of CAG repeats expansion in ATXN3. Body mass index (BMI) is an important modulatory factor in the progression of neurodegenerative disorders such as Huntington disease and amyotrophic lateral sclerosis. However, its relevance in SCA3 is not well understood. In this study, BMI was investigated in 134 molecularly confirmed SCA3 patients and 136 healthy controls from China. The multivariable linear regression models were performed to establish the putative risk factors for BMI, and whether BMI could affect the severity of ataxia. We found that BMI was significantly lower in the case group than that in the control group. The age at onset (positive correlation) and severity of ataxia (negative correlation) were the risk factors affecting BMI. Conversely, BMI along with the disease duration, the age at onset, and the numbers of CAG repeats could also have influence on the severity of ataxia. In conclusion, SCA3 patients had lower BMI than matched controls and BMI is a predictor of disease progression in SCA3. Nutritional intervention to promote weight gain could be a promising strategy to impede SCA3 progression.

Summary Primary familial brain calcification (PFBC) is a genetically heterogeneous disorder characterized by bilateral calcifications in the basal ganglia and other brain regions. The genetic basis of this disorder remains unknown in a significant portion of familial cases. Here, we reported a recessive causal gene, MYORG , for PFBC. Compound heterozygous or homozygous mutations of MYORG co-segregated completely with PFBC in six families, with logarithm of odds (LOD) score of 4.91 at the zero recombination fraction. In mice, Myorg mRNA was expressed specifically in S100β-positive astrocytes, and knockout of Myorg induced the formation of brain calcification at 9 months of age. Our findings provide strong evidence that loss-of-function mutations of MYORG cause brain calcification in humans and mice.

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder caused by survival motor neuron (SMN) protein deficiency leading the loss of motor neurons in the anterior horns of the spinal cord and brainstem. More than 95% of SMA patients are attributed to the homozygous deletion of survival motor neuron 1 (SMN1) gene, and approximately 5% are caused by compound heterozygous with a SMN1 deletion and a subtle mutation. Here, we identified a rare variant c.835-5T>G in intron 6 of SMN1 in a patient affected with type I SMA. We analyzed the functional consequences of this mutation on mRNA splicing in vitro. After transfecting pCI-SMN1, pCI-SMN2, and pCI-SMN1 c.835-5T>G minigenes into HEK293, Neuro-2a, and SHSY5Y cells, reverse transcription polymerase chain reaction (RT-PCR) was performed to compare the splicing effects of these minigenes. Finally, we found that this mutation resulted in the skipping of exon 7 in SMN1, which confirmed the genetic diagnosis of SMA.

Background Spinocerebellar ataxia type 3 (SCA3) is the most common subtype of SCAs worldwide. SCA3 homozygote is defined as expanded CAG repeats in both alleles that might exhibit severe phenotype due to gene dosage effect. However, a study on the systematic comparison of clinical phenotypes between homozygotes and heterozygotes to indicate these verity of phenotypes of homozygotes is still lacking. Methods A total of 14 SCA3 homozygotes (3 Chinese participants and 11 participants from various ethnicity in different published studies) and 143 Chinese heterozygotes of SCA3 were recruited for this study. The 95% confidence intervals (CIs) of age at onset and disease severity expected from heterozygous patients were analyzed to detect the phenotypic differences between homozygotes and heterozygotes. Results Almost all the homozygotes (13 of 14) were found to present a significant earlier age at onset compared with heterozygotes, because age at onset of most homozygotes was lower than the 95% CIs of age at onset of heterozygotes. Also, the clinical severity in most of the homozygotes (3 of 4) with identified clinical phenotypes was higher than the 95% CIs of severity in heterozygotes, indicating more severe clinical phenotypes in SCA3 homozygotes. Conclusions The homozygosity for SCA3 could lead to an earlier age of onset and putative severe clinical features. The findings of the present study suggested an influence of gene dosage on SCA3 phenotypes.

Table S1. The primer sequences for TARDBP gene. (DOC 19Â kb)

Pedigrees, sequencing chromatograms of disease-causing gene related to HSP families in our cohort. Figure S1. Pedigree, sequencing chromatograms of SPAST gene detected in 16 SPG4 families in our cohort. Figure S2. Western blot analysis of novel mutations of SPAST gene in HEK 293T cells. Figure S3. Pedigree, sequencing chromatograms of 6 ADHSP families in our cohort. Figure S4. Pedigree, sequencing chromatograms of CYP7B1 gene detected in 16 unrelated SPG5 families in our cohort. Figure S5. Pedigree, sequencing chromatograms of 5 ARHSP families in our cohort. (DOCX 9157 kb)

In the paper, we have studied one-dimensional step-wise linear photonic crystal with and without defect layer, and analyzed the effect of defect layer position, thickness, refractive index real part and imaginary part on the transmissivity, electric field distribution and output electric field intensity. By calculation, we have obtained a set of optimal parameters, which can be optimally designed optical device, such as optical amplifier, attenuator, optical diode by the step-wise linear photonic crystal.