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1.
Proc Natl Acad Sci U S A ; 121(26): e2403227121, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38885382

ABSTRACT

Treatment with autologous chimeric antigen receptor (CAR) T cells has emerged as a highly effective approach in neuroimmunological disorders such as myasthenia gravis. We report a case of successful anti-CD19 CAR T cell use in treatment-refractory stiff-person syndrome (SPS). To investigate clinical and immunological effects of anti-CD19 CAR T cell use in treatment-refractory SPS, a 69-y-old female with a 9-y history of treatment-refractory SPS with deteriorating episodes of stiffness received an infusion of autologous anti-CD19 CAR T cells (KYV-101) and was monitored clinically and immunologically for more than 6 mo. CAR T cell infusion resulted in reduced leg stiffness, drastic improvement in gait, walking speed increase over 100%, and daily walking distance improvement from less than 50 m to over 6 km within 3 mo. GABAergic medication (benzodiazepines) was reduced by 40%. KYV-101 CAR T cells were well tolerated with only low-grade cytokine release syndrome. This report of successful use of anti-CD19 CAR T cells in treatment-refractory SPS supports continued exploration of this approach in SPS and other B cell-related autoimmune disorders.


Subject(s)
Antigens, CD19 , Immunotherapy, Adoptive , Stiff-Person Syndrome , Humans , Stiff-Person Syndrome/therapy , Stiff-Person Syndrome/immunology , Female , Aged , Immunotherapy, Adoptive/methods , Antigens, CD19/immunology , Receptors, Chimeric Antigen/immunology , T-Lymphocytes/immunology , Treatment Outcome
2.
BMC Neurol ; 24(1): 272, 2024 Aug 03.
Article in English | MEDLINE | ID: mdl-39097681

ABSTRACT

BACKGROUND: Despite the frequent diagnostic delays of rare neurologic diseases (RND), it remains difficult to study RNDs and their comorbidities due to their rarity and hence the statistical underpowering. Affecting one to two in a million annually, stiff person syndrome (SPS) is an RND characterized by painful muscle spasms and rigidity. Leveraging underutilized electronic health records (EHR), this study showcased a machine-learning-based framework to identify clinical features that optimally characterize the diagnosis of SPS. METHODS: A machine-learning-based feature selection approach was employed on 319 items from the past medical histories of 48 individuals (23 with a diagnosis of SPS and 25 controls) with elevated serum autoantibodies against glutamic-acid-decarboxylase-65 (anti-GAD65) in Dartmouth Health's EHR to determine features with the highest discriminatory power. Each iteration of the algorithm implemented a Support Vector Machine (SVM) model, generating importance scores-SHapley Additive exPlanation (SHAP) values-for each feature and removing one with the least salient. Evaluation metrics were calculated through repeated stratified cross-validation. RESULTS: Depression, hypothyroidism, GERD, and joint pain were the most characteristic features of SPS. Utilizing these features, the SVM model attained precision of 0.817 (95% CI 0.795-0.840), sensitivity of 0.766 (95% CI 0.743-0.790), F-score of 0.761 (95% CI 0.744-0.778), AUC of 0.808 (95% CI 0.791-0.825), and accuracy of 0.775 (95% CI 0.759-0.790). CONCLUSIONS: This framework discerned features that, with further research, may help fully characterize the pathologic mechanism of SPS: depression, hypothyroidism, and GERD may respectively represent comorbidities through common inflammatory, genetic, and dysautonomic links. This methodology could address diagnostic challenges in neurology by uncovering latent associations and generating hypotheses for RNDs.


Subject(s)
Electronic Health Records , Machine Learning , Stiff-Person Syndrome , Humans , Stiff-Person Syndrome/diagnosis , Stiff-Person Syndrome/immunology , Stiff-Person Syndrome/epidemiology , Electronic Health Records/statistics & numerical data , Male , Female , Middle Aged , Aged , Adult , Support Vector Machine , Proof of Concept Study , Glutamate Decarboxylase/immunology , Rare Diseases/diagnosis , Autoantibodies/blood
3.
Pain Pract ; 24(5): 798-804, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38185725

ABSTRACT

BACKGROUND: Stiff person syndrome (SPS) is a rare neuroimmunological disorder characterized by rigidity and painful spasm primarily affecting the truncal and paraspinal musculature due to autoimmune-mediated neuronal hyperexcitability. Spinal cord stimulation (SCS) is an approved therapy for managing painful neuropathic conditions, including diabetic peripheral neuropathy and refractory angina pectoris. We describe the novel use of SCS for the treatment of spasm and rigidity in a 49-year-old man with seropositive stiff person syndrome (SPS). The patient was treated with intravenous immunoglobulin (IVIG) and oral medications over a 13-month period with minimal improvement, prompting consideration of SCS. To our knowledge, this is the first report of the successful use of SCS in SPS with the demonstration of multifaceted clinical improvement. METHODS: Following a successful temporary SCS trial, permanent implantation was performed. Spasm/stiffness (Distribution of Stiffness Index; Heightened Sensitivity Scale; Penn Spasm Frequency Scale, PSFS), disability (Oswestry Disability Index, ODI; Pain Disability Index, PDI), depression (Patient Health Questionnaire-9, PHQ-9), sleep (Pittsburgh Sleep Quality Index, PSQI), fatigue (Fatigue Severity Scale, FSS), pain (Numerical Pain Rating Scale, NPRS), quality of life (EuroQoL 5 Dimension 5 Level, EQ-5D-5L), and medication usage were assessed at baseline, 6-month, and 10-month postimplantation. RESULTS: ODI, PHQ-9, FSS, NPRS, PSQI, and EQ-5D-5L scores showed a notable change from baseline and surpassed the defined minimal clinically important difference (MCID) at 6-month and 10-month follow-up. Oral medication dosages were reduced. CONCLUSIONS: The novel use of SCS therapy in seropositive SPS resulted in functional improvement and attenuation of symptoms. We present possible mechanisms by which SCS may produce clinical response in patients with SPS and aim to demonstrate proof-of-concept for a future comprehensive pilot study evaluating SCS-mediated response in SPS.


Subject(s)
Spinal Cord Stimulation , Stiff-Person Syndrome , Humans , Stiff-Person Syndrome/therapy , Stiff-Person Syndrome/complications , Male , Middle Aged , Spinal Cord Stimulation/methods , Muscle Rigidity/therapy , Muscle Rigidity/etiology , Spasm/therapy , Spasm/etiology , Treatment Outcome
4.
Hum Genet ; 142(8): 1221-1230, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37222814

ABSTRACT

Hereditary hyperekplexia is a rare neuronal disorder characterized by an exaggerated startle response to sudden tactile or acoustic stimuli. In this study, we present a Miniature Australian Shepherd family showing clinical signs, which have genetic and phenotypic similarities with human hereditary hyperekplexia: episodes of muscle stiffness that could occasionally be triggered by acoustic stimuli. Whole genome sequence data analysis of two affected dogs revealed a 36-bp deletion spanning the exon-intron boundary in the glycine receptor alpha 1 (GLRA1) gene. Further validation in pedigree samples and an additional cohort of 127 Miniature Australian Shepherds, 45 Miniature American Shepherds and 74 Australian Shepherds demonstrated complete segregation of the variant with the disease, according to an autosomal recessive inheritance pattern. The protein encoded by GLRA1 is a subunit of the glycine receptor, which mediates postsynaptic inhibition in the brain stem and spinal cord. The canine GLRA1 deletion is located in the signal peptide and is predicted to cause exon skipping and subsequent premature stop codon resulting in a significant defect in glycine signaling. Variants in GLRA1 are known to cause hereditary hyperekplexia in humans; however, this is the first study to associate a variant in canine GLRA1 with the disorder, establishing a spontaneous large animal disease model for the human condition.


Subject(s)
Hyperekplexia , Stiff-Person Syndrome , Humans , Dogs , Animals , Hyperekplexia/genetics , Stiff-Person Syndrome/genetics , Stiff-Person Syndrome/veterinary , Receptors, Glycine/genetics , Australia
5.
Eur J Neurol ; 30(8): 2498-2505, 2023 08.
Article in English | MEDLINE | ID: mdl-37154293

ABSTRACT

BACKGROUND AND PURPOSE: Stiff person syndrome (SPS) spectrum disorders (SPSSD) cause spasms and rigidity throughout different body regions and can be associated with apnea and acute respiratory failure. There are limited data on the prevalence and predictors of respiratory symptoms with spasms (RSwS) in SPSSD. We sought to characterize the spirometry patterns and the frequency and predictors of RSwS in a large SPSSD cohort. METHODS: Participants were recruited from the Johns Hopkins SPS Center between 1997 and 2021, as part of an ongoing, longitudinal observational study. Medical records were reviewed to assess demographics and clinical characteristics. Data were analyzed using descriptive statistics and multivariable logistic regression models. RESULTS: One-hundred ninety-nine participants (mean age = 53.4 ± 13.6 years, median time to diagnosis = 36 [IQR 66] months, 74.9% women, 69.8% White, 62.8% classic SPS phenotype) were included in final analyses; 35.2% of participants reported RSwS, of whom 24.3% underwent spirometry as part of routine clinical care. Obstructive (23.5%) and restrictive (23.5%) patterns were most commonly observed in those with SPSSD. An increasing number of body regions involved predicted the presence of RSwS (odds ratio [OR] = 1.95, 95% confidence interval [CI] = 1.50-2.53); those with ≥5 body regions involved (vs. ≤4) had higher odds (OR = 6.19, 95% CI = 2.81-13.62) of experiencing RSwS in adjusted models. Two patients died from SPSSD-associated respiratory compromise. CONCLUSIONS: RSwS are common in SPSSD and may be predicted by an increasing number of body regions involved by SPSSD. Close clinical monitoring and having a low threshold to obtain spirometry should be considered in people with SPSSD.


Subject(s)
Stiff-Person Syndrome , Humans , Female , Male , Stiff-Person Syndrome/complications , Stiff-Person Syndrome/diagnosis , Stiff-Person Syndrome/epidemiology , Phenotype , Prevalence
6.
J Neuroophthalmol ; 43(2): 273-276, 2023 06 01.
Article in English | MEDLINE | ID: mdl-36728609

ABSTRACT

ABSTRACT: A 68-year-old woman with positional dizziness and progressive imbalance presented for vestibular evaluation. Examination was notable for spontaneous downbeat nystagmus (DBN), horizontal and vertical gaze-evoked nystagmus (GEN) with centripetal and rebound nystagmus, and positional apogeotropic nystagmus. There was also mild-moderate slowing of saccades horizontally and vertically and poor fast phases with an optokinetic stimulus. Further consultation by a movement disorder specialist uncovered asymmetric decrementing bradykinesia and rigidity, masked facies, and a wide-based stance without camptocormia. Screening serum laboratory results for metabolic, rheumatologic, infectious, heavy metal, endocrine, or vitamin abnormalities was normal. Surveillance imaging for neoplasms was unremarkable, and cerebrospinal fluid (CSF) analysis was negative for 14-3-3 and real-time quaking-induced conversion (RT-QuIC). However, her anti-glutamic acid decarboxylase-65 (GAD65) immunoglobulin G (IgG) level was markedly elevated in serum to 426,202 IU/mL (reference range 0-5 IU/mL) and in CSF to 18.1 nmol/L (reference range <0.03 nmol/L). No other autoantibodies were identified on the expanded paraneoplastic panel. The patient was referred to neuroimmunology, where torso rigidity, spasticity, and significant paravertebral muscle spasms were noted. Overall, the clinical presentation, examination findings, and extensive workup were consistent with a diagnosis of anti-GAD65-associated stiff person syndrome-plus (musculoskeletal plus cerebellar and/or brainstem involvement). She was subsequently treated with intravenous immunoglobulin (IVIg) and has been stable since commencing this therapy. In patients with centripetal nystagmus, especially in association with other cerebellar findings, an autoimmune cerebellar workup should be considered.


Subject(s)
Cerebellar Ataxia , Nystagmus, Pathologic , Parkinsonian Disorders , Stiff-Person Syndrome , Female , Humans , Aged , Saccades , Stiff-Person Syndrome/complications , Stiff-Person Syndrome/diagnosis , Stiff-Person Syndrome/drug therapy , Glutamate Decarboxylase , Nystagmus, Pathologic/diagnosis , Nystagmus, Pathologic/etiology , Nystagmus, Pathologic/drug therapy , Autoantibodies , Parkinsonian Disorders/complications , Parkinsonian Disorders/diagnosis
8.
Neuropediatrics ; 53(2): 136-139, 2022 04.
Article in English | MEDLINE | ID: mdl-34905789

ABSTRACT

Antiglutamic acid decarboxylase (GAD65) encephalitis is rare and few pediatric cases have been reported, with variable clinical presentations. A 14-year-old female adolescent was managed in our department. She had been treated for several months for drug-resistant temporal lobe epilepsy and gradually presented major anterograde amnesia with confusion. Upon her arrival at the University Hospital Centre, she showed a classical form of stiff person syndrome. The brain magnetic resonance imaging showed bitemporal hyperintensities and hypertrophy of the amygdala. The blood and cerebrospinal fluid were positive for GAD65 antibodies. At 2 years of immunosuppressive treatment and rehabilitation, the course showed partial improvement of the memory and neuropsychiatric impairment, and epilepsy that continued to be active. GAD65 antibodies are associated with various neurological syndromes, and this presentation combining limbic encephalitis and stiff person syndrome is the first pediatric form published to date; there are also few cases described in adults.


Subject(s)
Amnesia, Anterograde , Drug Resistant Epilepsy , Encephalitis , Limbic Encephalitis , Stiff-Person Syndrome , Adolescent , Adult , Autoantibodies , Child , Encephalitis/complications , Encephalitis/diagnosis , Female , Glutamate Decarboxylase , Humans , Limbic Encephalitis/complications , Limbic Encephalitis/diagnosis , Magnetic Resonance Imaging , Stiff-Person Syndrome/complications , Stiff-Person Syndrome/diagnosis
9.
Neurol Sci ; 43(1): 633-641, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33914193

ABSTRACT

OBJECTIVES: To explore different neurological manifestations with suspicion of being associated to serum glutamate decarboxylase antibodies (GAD-Abs) in order to better characterize anti-GAD neurological syndromes. METHODS: Observational retrospective study including all patients for whom GAD65-Abs titers in serum were requested by the Neurology Department at La Paz University Hospital between 2015 and 2019. GAD-Abs were measured by ELISA. Demographic data, neurological symptoms, comorbidity with diabetes mellitus (DM) or with another autoimmune disease, and GAD-Abs titers were studied. Stiff-person syndrome, ataxia, encephalitis, and epilepsy were considered typical anti-GAD neurological syndromes and were compared to other atypical manifestations. RESULTS: A total of 173 patients (51.7% men, mean age 51.62) were included. A progressive increase in requests of serum GAD-Abs has occurred over the last 5 years, especially in patients with atypical neurological manifestations. GAD-Abs were found in the serum of 22 patients (12.7%); of those, 15 (68.18%) suffered a typical anti-GAD syndrome. Presence of DM or another organ-specific autoimmune disease was predictive of GAD-AB seropositivity (p < 0.001). 6.6% of requested patients with an atypical syndrome had GAD-Abs, but serum levels were significantly lower than those found in patients with a typical syndrome (706.67 vs 1430.23 UI/mL; Mann-Whitney U, p = 0.034), and were finally diagnosed with another neurological disease. CONCLUSION: Serum GAD-Abs were infrequently found in patients with clinical phenotypes other than those classically described as anti-GAD disorders, and with very low titers. In typical anti-GAD syndromes, there is a high comorbidity with DM and with other autoimmune diseases, and high serum GAD-Abs levels are usually present.


Subject(s)
Autoantibodies/blood , Nervous System Diseases , Ataxia , Autoimmune Diseases , Comorbidity , Diabetes Mellitus , Encephalitis , Epilepsy , Female , Glutamate Decarboxylase/immunology , Humans , Male , Middle Aged , Nervous System Diseases/diagnosis , Nervous System Diseases/epidemiology , Retrospective Studies , Stiff-Person Syndrome
10.
Can J Anaesth ; 69(11): 1419-1425, 2022 11.
Article in English | MEDLINE | ID: mdl-35986141

ABSTRACT

PURPOSE: Stiff person syndrome (SPS), an autoimmune disease that manifests with episodic muscle rigidity and spasms, has anesthetic considerations because postoperative hypotonia may occur. This hypotonia has been linked to muscle relaxants and volatile anesthetics and may persist in spite of neostigmine administration and train-of-four (TOF) monitoring suggesting full reversal. We present a patient with SPS who experienced hypotonia following total intravenous anesthesia (TIVA), which was promptly reversed with sugammadex. These observations are considered in light of the relevant medical literature. CLINICAL FEATURES: A 46-yr-old female patient with SPS underwent breast lumpectomy and sentinel node biopsy. Anesthesia consisted of TIVA (propofol/remifentanil) with adjunctive administration of rocuronium 20 mg to obtain adequate intubating conditions. Despite return of the TOF ratio to 100% within 30 min, hypotonia was clinically evident at conclusion of surgery two hours later. Sugammadex 250 mg reversed residual muscle relaxation permitting uneventful extubation. A literature review identified six instances of postoperative hypotonia (TIVA, n = 3; volatile anesthetics, n = 3) in spite of neostigmine administration (n = 2) and TOF monitoring suggesting full reversal (n = 4). CONCLUSIONS: Patients with SPS may show hypotonia regardless of general anesthetic technique (TIVA vs inhalational anesthesia), which can persist despite recovery of the TOF ratio and may be more effectively reversed by a chelating agent than with an anticholinesterase. If general anesthesia is required, we suggest a cautious approach to administering muscle relaxants including using the smallest dose necessary, considering the importance of clinical assessment of muscle strength recovery in addition to TOF monitoring, and discussing postoperative ventilation risk with the patient prior to surgery.


RéSUMé: OBJECTIF: Le syndrome de la personne raide (SPR), une maladie auto-immune qui se manifeste par une rigidité musculaire et des spasmes épisodiques, requiert certaines considérations anesthésiques en raison du risque d'hypotonie postopératoire. Cette hypotonie a été liée à des myorelaxants et à des anesthésiques volatils et peut persister malgré l'administration de néostigmine et un monitorage du train-de-quatre (TDQ) suggérant une neutralisation complète. Nous présentons le cas d'une patiente atteinte de SPR qui a souffert d'hypotonie après une anesthésie intraveineuse totale (TIVA), laquelle a été rapidement neutralisée à l'aide de sugammadex. Ces observations sont examinées à la lumière de la littérature médicale pertinente. CARACTéRISTIQUES CLINIQUES: Une patiente de 46 ans atteinte de SPR a bénéficié d'une tumorectomie mammaire et d'une biopsie du ganglion sentinelle. L'anesthésie consistait en une TIVA (propofol/rémifentanil) avec administration d'appoint de 20 mg de rocuronium pour atteindre des conditions d'intubation adéquates. Malgré le retour du ratio de TdQ à 100 % dans les 30 minutes, l'hypotonie était cliniquement évidente à la fin de la chirurgie deux heures plus tard. L'administration de 250 mg de sugammadex a neutralisé la relaxation musculaire résiduelle, permettant une extubation sans incident. Une revue de la littérature a identifié six cas d'hypotonie postopératoire (TIVA, n = 3; anesthésiques volatils, n = 3) malgré l'administration de néostigmine (n = 2) et le monitorage du TdQ suggérant une neutralisation complète (n = 4). CONCLUSION: Les patients atteints de SPR peuvent présenter une hypotonie quelle que soit la technique d'anesthésie générale utilisée (TIVA vs anesthésie par inhalation), laquelle peut persister malgré la récupération du rapport de TdQ; cette hypotonie peut être plus efficacement neutralisée par un agent chélateur qu'avec un anticholinestérasique. Si une anesthésie générale est nécessaire, nous suggérons une approche prudente pour l'administration de myorelaxants, y compris l'utilisation de la plus petite dose nécessaire, la prise en compte de l'importance de l'évaluation clinique de la récupération de la force musculaire en plus du monitorage du TdQ, et la communication du risque de ventilation postopératoire au patient avant la chirurgie.


Subject(s)
Anesthetics, Inhalation , Neuromuscular Blockade , Propofol , Stiff-Person Syndrome , Humans , Female , Rocuronium , Sugammadex , Neostigmine , Stiff-Person Syndrome/complications , Cholinesterase Inhibitors , Remifentanil , Muscle Hypotonia , Anesthetics, Inhalation/adverse effects , Chelating Agents , Neuromuscular Blockade/methods
11.
Int J Mol Sci ; 23(8)2022 Apr 17.
Article in English | MEDLINE | ID: mdl-35457242

ABSTRACT

Two isoforms of the glutamate decarboxylase (GAD) enzyme exist, GAD65 and GAD67, which are associated with type 1 diabetes (T1D) and stiff-person syndrome (SPS), respectively. Interestingly, it has been reported that T1D patients seldom develop SPS, whereas patients with SPS occasionally develop T1D. In addition, coxsackievirus B4 (CVB4) has previously been proposed to be involved in the onset of T1D through molecular mimicry. On this basis, we aimed to examine antibody cross-reactivity between a specific region of GAD65 and GAD67, which has high sequence homology to the nonstructural P2C protein of CVB4 to determine potential correlations at antibody level. Monoclonal peptide antibodies generated in mice specific for a region with high similarity in all three proteins were screened for reactivity along with human sera in immunoassays. In total, six antibodies were generated. Two of the antibodies reacted to both GAD isoforms. However, none of the antibodies were cross-reactive to CVB, suggesting that antibody cross-reactivity between GAD65 and CVB, and GAD67 and CVB may not contribute to the onset of T1D and SPS, respectively.


Subject(s)
Diabetes Mellitus, Type 1 , Stiff-Person Syndrome , Animals , Antibodies, Monoclonal , Autoantibodies , Glutamate Decarboxylase/metabolism , Humans , Mice , Peptides , Protein Isoforms
12.
Pract Neurol ; 22(1): 48-50, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34321329

ABSTRACT

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a subtype of stiff-person syndrome (formerly stiff-man syndrome). It is rare and disabling, and characterised by brainstem symptoms, muscle stiffness, breathing issues and autonomic dysfunction. We describe a 65-year-old man who presented with odynophagia together with tongue and neck swelling, followed by multiple cranial nerve palsies culminating in bilateral vocal cord paralysis with acute stridor. He subsequently developed progressive generalised hypertonia and painful limb spasms. Serum antiglycine receptor antibody was strongly positive, but antiglutamic acid decarboxylase and other antibodies relating to stiff-person syndrome were negative. We diagnosed PERM and gave intravenous corticosteroids and immunoglobulins without benefit; however, following plasma exchange he has made a sustained improvement.


Subject(s)
Encephalomyelitis , Myoclonus , Stiff-Person Syndrome , Aged , Encephalomyelitis/complications , Humans , Male , Muscle Rigidity/complications , Myoclonus/complications , Stiff-Person Syndrome/complications
13.
J Neurosci ; 40(25): 4954-4969, 2020 06 17.
Article in English | MEDLINE | ID: mdl-32354853

ABSTRACT

Glycine receptors (GlyRs) are the major mediators of fast synaptic inhibition in the adult human spinal cord and brainstem. Hereditary mutations to GlyRs can lead to the rare, but potentially fatal, neuromotor disorder hyperekplexia. Most mutations located in the large intracellular domain (TM3-4 loop) of the GlyRα1 impair surface expression levels of the receptors. The novel GLRA1 mutation P366L, located in the TM3-4 loop, showed normal surface expression but reduced chloride currents, and accelerated whole-cell desensitization observed in whole-cell recordings. At the single-channel level, we observed reduced unitary conductance accompanied by spontaneous opening events in the absence of extracellular glycine. Using peptide microarrays and tandem MS-based analysis methods, we show that the proline-rich stretch surrounding P366 mediates binding to syndapin I, an F-BAR domain protein involved in membrane remodeling. The disruption of the noncanonical Src homology 3 recognition motif by P366L reduces syndapin I binding. These data suggest that the GlyRα1 subunit interacts with intracellular binding partners and may therefore play a role in receptor trafficking or synaptic anchoring, a function thus far only ascribed to the GlyRß subunit. Hence, the P366L GlyRα1 variant exhibits a unique set of properties that cumulatively affect GlyR functionality and thus might explain the neuropathological mechanism underlying hyperekplexia in the mutant carriers. P366L is the first dominant GLRA1 mutation identified within the GlyRα1 TM3-4 loop that affects GlyR physiology without altering protein expression at the whole-cell and surface levels.SIGNIFICANCE STATEMENT We show that the intracellular domain of the inhibitory glycine receptor α1 subunit contributes to trafficking and synaptic anchoring. A proline-rich stretch in this receptor domain forms a noncanonical recognition motif important for the interaction with syndapin I (PACSIN1). The disruption of this motif, as present in a human patient with hyperekplexia led to impaired syndapin I binding. Functional analysis revealed that the altered proline-rich stretch determines several functional physiological parameters of the ion channel (e.g., faster whole-cell desensitization) reduced unitary conductance and spontaneous opening events. Thus, the proline-rich stretch from the glycine receptor α1 subunit represents a multifunctional intracellular protein motif.


Subject(s)
Receptors, Glycine/genetics , Receptors, Glycine/metabolism , Stiff-Person Syndrome/genetics , Adaptor Proteins, Signal Transducing/metabolism , Amino Acid Motifs , Animals , Humans , Mutation , Protein Binding/genetics , Protein Structure, Quaternary , Protein Transport/genetics , Receptors, Glycine/chemistry
14.
Ann Neurol ; 88(3): 544-561, 2020 09.
Article in English | MEDLINE | ID: mdl-32588476

ABSTRACT

OBJECTIVE: Impairment of glycinergic neurotransmission leads to complex movement and behavioral disorders. Patients harboring glycine receptor autoantibodies suffer from stiff-person syndrome or its severe variant progressive encephalomyelitis with rigidity and myoclonus. Enhanced receptor internalization was proposed as the common molecular mechanism upon autoantibody binding. Although functional impairment of glycine receptors following autoantibody binding has recently been investigated, it is still incompletely understood. METHODS: A cell-based assay was used for positive sample evaluation. Glycine receptor function was assessed by electrophysiological recordings and radioligand binding assays. The in vivo passive transfer of patient autoantibodies was done using the zebrafish animal model. RESULTS: Glycine receptor function as assessed by glycine dose-response curves showed significantly decreased glycine potency in the presence of patient sera. Upon binding of autoantibodies from 2 patients, a decreased fraction of desensitized receptors was observed, whereas closing of the ion channel remained fast. The glycine receptor N-terminal residues 29 A to 62 G were mapped as a common epitope of glycine receptor autoantibodies. An in vivo transfer into the zebrafish animal model generated a phenotype with disturbed escape behavior accompanied by a reduced number of glycine receptor clusters in the spinal cord of affected animals. INTERPRETATION: Autoantibodies against the extracellular domain mediate alterations of glycine receptor physiology. Moreover, our in vivo data demonstrate that the autoantibodies are a direct cause of the disease, because the transfer of human glycine receptor autoantibodies to zebrafish larvae generated impaired escape behavior in the animal model compatible with abnormal startle response in stiff-person syndrome or progressive encephalitis with rigidity and myoclonus patients. ANN NEUROL 2020;88:544-561.


Subject(s)
Autoantibodies/immunology , Encephalomyelitis/immunology , Muscle Rigidity/immunology , Receptors, Glycine/metabolism , Stiff-Person Syndrome/immunology , Adult , Aged , Animals , Autoantibodies/pharmacology , Autoantigens/immunology , Behavior, Animal/drug effects , Encephalomyelitis/metabolism , Epitopes, B-Lymphocyte/immunology , Female , Humans , Male , Middle Aged , Muscle Rigidity/metabolism , Receptors, Glycine/immunology , Stiff-Person Syndrome/metabolism , Zebrafish
15.
Neurol Sci ; 42(10): 4095-4107, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34379238

ABSTRACT

Startle, a basic alerting reaction common to all mammals, is described as a sudden involuntary movement of the body evoked by all kinds of sudden and unexpected stimulus. Startle syndromes are heterogeneous groups of disorders with abnormal and exaggerated responses to startling events, including hyperekplexia, stimulus-induced disorders, and neuropsychiatric startle syndromes. Hyperekplexia can be attributed to a genetic, idiopathic, or symptomatic cause. Excluding secondary factors, hereditary hyperekplexia, a rare neurogenetic disorder with highly genetic heterogeneity, is characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli, and followed by a short period of general stiffness. It mainly arises from defects of inhibitory glycinergic neurotransmission. GLRA1 is the major pathogenic gene of hereditary hyperekplexia, along with many other genes involved in the function of glycinergic inhibitory synapses. While about 40% of patients remain negative genetic findings. Clonazepam, which can specifically upgrade the GABARA1 chloride channels, is the main and most effective administration for hereditary hyperekplexia patients. In this review, with the aim at enhancing the recognition and prompting potential treatment for hyperekplexia, we focused on discussing the advances in hereditary hyperekplexia genetics and the expound progress in pathogenic mechanisms of the glycinergic-synapse-related pathway and then followed by a brief overview of other common startle syndromes.


Subject(s)
Hyperekplexia , Stiff-Person Syndrome , Animals , Humans , Hyperekplexia/genetics , Infant, Newborn , Muscle Rigidity , Receptors, Glycine/genetics , Reflex, Startle/genetics , Stiff-Person Syndrome/genetics
16.
J Musculoskelet Neuronal Interact ; 21(2): 322-325, 2021 06 01.
Article in English | MEDLINE | ID: mdl-34059578

ABSTRACT

We aimed to share our rehabilitation experience in a patient diagnosed with paraneoplastic Stiff-person syndrome(SPS). A 45-year-old female patient was admitted to neurology with the complaint of widespread painful contractions. EMG was evaluated in favor of SPS. Amphiphysin-antibody was +++ in CSF. Patients' treatment was arranged and transferred to rehabilitation inpatient-clinic. The patient was included in the rehabilitation program of range of motion, stretching, strengthening, posture&walking exercises, balance&coordination exercises, 5 days/week for 3 months. The patient was screened for breast cancer, diagnosed with invasive breast carcinoma and underwent mastectomy. With the rehabilitation, the patient was mobilized first in the parallel-bar then with tripod-cane in the following months. Significant improvements were found in functional status and quality of life with control of spasticity and mobilization. Although the primary treatment of paraneoplastic SPS is cancer treatment, significant gains have been achieved with rehabilitation. It is necessary to raise awareness of the importance of rehabilitation to physicians who diagnose the disease.


Subject(s)
Stiff-Person Syndrome , Autoantibodies , Breast Neoplasms/complications , Female , Humans , Mastectomy , Middle Aged , Quality of Life
17.
Curr Pain Headache Rep ; 25(5): 32, 2021 Mar 24.
Article in English | MEDLINE | ID: mdl-33760994

ABSTRACT

PURPOSE OF REVIEW: Chest pain is a very common presenting complaint among patients in the hospital, a large proportion of whom have non-cardiac chest pain (NCCP). Neurological causes of NCCP have not been previously reviewed although several causes have been identified. RECENT FINDINGS: Chest pain has been reported as a symptom of multiple neurological conditions such as migraine, epilepsy, and multiple sclerosis, with varying clinical presentations. The affected patients are often not formally diagnosed for long periods of time due to difficulties in recognizing the symptoms as part of neurological disease processes. This paper will briefly summarize well-known etiologies of chest pain and, then, review neurological causes of NCCP, providing an overview of current literature and possible pathophysiologic mechanisms.


Subject(s)
Chest Pain/etiology , Nervous System Diseases/complications , Central Nervous System Sensitization , Chest Pain/physiopathology , Complex Regional Pain Syndromes/complications , Complex Regional Pain Syndromes/physiopathology , Epilepsy/complications , Epilepsy/physiopathology , Guillain-Barre Syndrome/complications , Guillain-Barre Syndrome/physiopathology , Herpes Zoster/complications , Herpes Zoster/physiopathology , Humans , Migraine Disorders/complications , Migraine Disorders/physiopathology , Nervous System Diseases/physiopathology , Neuralgia, Postherpetic/complications , Neuralgia, Postherpetic/physiopathology , Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/complications , Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/physiopathology , Radiculopathy/complications , Radiculopathy/physiopathology , Spinal Nerve Roots , Stiff-Person Syndrome/complications , Stiff-Person Syndrome/physiopathology , Stroke/complications , Stroke/physiopathology
18.
J Neuroophthalmol ; 41(4): e665-e671, 2021 12 01.
Article in English | MEDLINE | ID: mdl-33105411

ABSTRACT

BACKGROUND: Antiglutamic acid decarboxylase (GAD)-associated neurologic disorders are rare, with varied presentations, including stiff-person syndrome (SPS) and cerebellar ataxia (CA). Vestibular and ocular motor (VOM) dysfunction can be the main presentation in a subset of patients. METHODS: Retrospective review of the Johns Hopkins Hospital medical records from 1997 to 2018 identified a total of 22 patients with a diagnosis of anti-GAD-associated SPS or CA who had detailed VOM assessments. Eight had prominent VOM dysfunction at the initial symptom onset and were referred to neurology from ophthalmology or otolaryngology ("early dominant"). Fourteen patients had VOM dysfunction that was not their dominant presentation and were referred later in their disease course from neurology to neuro-ophthalmology ("nondominant"). We reviewed clinical history, immunological profiles, and VOM findings, including available video-oculography. RESULTS: In the 8 patients with early dominant VOM dysfunction, the average age of symptom onset was 53 years, and 5 were men. The most common symptom was dizziness, followed by diplopia. Seven had features of CA, and 4 had additional features of SPS. None had a structural lesion on brain MRI accounting for their symptoms. The most common VOM abnormalities were downbeating and gaze-evoked nystagmus and saccadic pursuit. All received immune therapy and most received symptomatic therapy. Most experienced improvement in clinical outcome measures (modified Rankin scale and/or timed 25-foot walk test) or VOM function. By contrast, in the 14 patients in whom VOM dysfunction was nondominant, most had an SPS phenotype and were women. VOM abnormalities, when present, were more subtle, although mostly still consistent with cerebellar and/or brainstem dysfunction. CONCLUSIONS: Individuals with anti-GAD-associated neurologic disorders may present with prominent VOM abnormalities at the initial symptom onset that localize to the cerebellum and/or brainstem. In our cohort, immune and symptomatic therapies improved clinical outcomes and symptomatology.


Subject(s)
Carboxy-Lyases , Cerebellar Ataxia , Nervous System Diseases , Stiff-Person Syndrome , Carboxy-Lyases/therapeutic use , Cerebellar Ataxia/complications , Eye Movements , Female , Glutamate Decarboxylase , Humans , Stiff-Person Syndrome/complications , Stiff-Person Syndrome/diagnosis , Stiff-Person Syndrome/therapy
19.
Ann Neurol ; 85(3): 448-454, 2019 03.
Article in English | MEDLINE | ID: mdl-30635933

ABSTRACT

High levels of antibodies against glutamic acid decarboxylase (GAD) are observed in patients with different neurological disorders, but cells producing these autoantibodies are largely unexplored. We detect circulating GAD-reactive B cells in peripheral blood that readily differentiate into antibody-producing cells. These cells are highly elevated in most patients with GAD-antibody-associated disorders (n = 15) compared to controls (n = 19). They mainly produce GAD65 antibodies of the IgG1 and IgG4 subclasses and are as abundant as B cells reactive for common recall antigens. Bone marrow cells represent an additional source of GAD antibodies. The identification of GAD-antibody-producing cells has implications for the selection of cell-specific biologics. ANN NEUROL 2019;85:448-454.


Subject(s)
Autoantibodies/immunology , B-Lymphocytes/immunology , Cerebellar Ataxia/immunology , Glutamate Decarboxylase/immunology , Limbic Encephalitis/immunology , Plasma Cells/immunology , Stiff-Person Syndrome/immunology , Adolescent , Adult , Aged , Bone Marrow Cells/immunology , Case-Control Studies , Female , Humans , Immunoglobulin G/immunology , Leukocytes, Mononuclear/immunology , Male , Middle Aged , Young Adult
20.
Cerebellum ; 19(5): 715-721, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32592031

ABSTRACT

A prompt diagnosis and treatment of patients with autoimmune cerebellar ataxia (CA) with antibodies against glutamic acid decarboxylase (GAD-Abs) may lead to a better prognosis. Herein, we report prodromal transient neurological symptoms that should raise clinical suspicion of CA with GAD-Abs. We initially identified a 70-year-old man who presented a first acute episode of vertigo, diplopia, and ataxia lasting 2 weeks. Two months later, he experienced a similar episode along with new-onset gaze-evoked nystagmus. After 4 months, downbeat nystagmus, left limb dysmetria, and gait ataxia progressively appeared, and an autoimmune CA was diagnosed based on the positivity of GAD-Abs in serum and cerebrospinal fluid (CSF). We searched retrospectively for similar presentations in a cohort of 31 patients diagnosed with CA and GAD-Abs. We found 11 (35.4%) patients (all women, median age 62 years; 8/11 [72.7%] with autoimmune comorbidities) with transient neurological symptoms antedating CA onset by a median of 3 months, including vertigo in 9 (81.8%; described as paroxysmal in 8) and fluctuating diplopia in 3 (27.3%) patients. The identification of transient neurological symptoms of unknown etiology, such as paroxysmal vertigo and fluctuating diplopia, should lead to GAD-Abs testing in serum and CSF, especially in patients with autoimmune comorbidities.


Subject(s)
Cerebellar Ataxia/drug therapy , Gait Ataxia/drug therapy , Glutamate Decarboxylase/pharmacology , Stiff-Person Syndrome/drug therapy , Aged , Autoantibodies/blood , Cerebellar Ataxia/complications , Cerebellar Ataxia/diagnosis , Glutamate Decarboxylase/immunology , Humans , Retrospective Studies , Stiff-Person Syndrome/complications
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