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Tannemaat MR, Huijbers MG, Verschuuren JJGM. Myasthenia gravis-Pathophysiology, diagnosis, and treatment. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:283-305. [PMID: 38494283 DOI: 10.1016/b978-0-12-823912-4.00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.
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Affiliation(s)
- Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Ruiter AM, Wang Z, Yin Z, Naber WC, Simons J, Blom JT, van Gemert JC, Verschuuren JJGM, Tannemaat MR. Assessing facial weakness in myasthenia gravis with facial recognition software and deep learning. Ann Clin Transl Neurol 2023; 10:1314-1325. [PMID: 37292032 PMCID: PMC10424649 DOI: 10.1002/acn3.51823] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/10/2023] Open
Abstract
OBJECTIVE Myasthenia gravis (MG) is an autoimmune disease leading to fatigable muscle weakness. Extra-ocular and bulbar muscles are most commonly affected. We aimed to investigate whether facial weakness can be quantified automatically and used for diagnosis and disease monitoring. METHODS In this cross-sectional study, we analyzed video recordings of 70 MG patients and 69 healthy controls (HC) with two different methods. Facial weakness was first quantified with facial expression recognition software. Subsequently, a deep learning (DL) computer model was trained for the classification of diagnosis and disease severity using multiple cross-validations on videos of 50 patients and 50 controls. Results were validated using unseen videos of 20 MG patients and 19 HC. RESULTS Expression of anger (p = 0.026), fear (p = 0.003), and happiness (p < 0.001) was significantly decreased in MG compared to HC. Specific patterns of decreased facial movement were detectable in each emotion. Results of the DL model for diagnosis were as follows: area under the curve (AUC) of the receiver operator curve 0.75 (95% CI 0.65-0.85), sensitivity 0.76, specificity 0.76, and accuracy 76%. For disease severity: AUC 0.75 (95% CI 0.60-0.90), sensitivity 0.93, specificity 0.63, and accuracy 80%. Results of validation, diagnosis: AUC 0.82 (95% CI: 0.67-0.97), sensitivity 1.0, specificity 0.74, and accuracy 87%. For disease severity: AUC 0.88 (95% CI: 0.67-1.0), sensitivity 1.0, specificity 0.86, and accuracy 94%. INTERPRETATION Patterns of facial weakness can be detected with facial recognition software. Second, this study delivers a 'proof of concept' for a DL model that can distinguish MG from HC and classifies disease severity.
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Affiliation(s)
- Annabel M. Ruiter
- Department of NeurologyLeiden University Medical CenterLeidenthe Netherlands
| | - Ziqi Wang
- Vision LabDelft University of TechnologyDelftthe Netherlands
| | - Zhao Yin
- Vision LabDelft University of TechnologyDelftthe Netherlands
| | - Willemijn C. Naber
- Department of NeurologyLeiden University Medical CenterLeidenthe Netherlands
| | - Jerrel Simons
- Department of NeurologyLeiden University Medical CenterLeidenthe Netherlands
| | - Jurre T. Blom
- Medical Illustrator at www.jurreblom.nlApeldoornthe Netherlands
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Lobban D, Oliver J, Davio K, Seddik K, Porkess V. Evaluation of the quality of patient involvement in a patient-led analysis of the lived experience of a rare disease. RESEARCH INVOLVEMENT AND ENGAGEMENT 2023; 9:35. [PMID: 37231525 PMCID: PMC10214587 DOI: 10.1186/s40900-023-00445-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 05/09/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND Patients themselves are best placed to provide insights on the lived experience and to lead the analysis of such insights to bring the patient voice into peer-reviewed literature. In doing so, they can meet the authorship criteria for subsequent research publications. It is important to evaluate patient engagement to identify ways to improve future collaborations. Here, we describe the approach taken during a patient-led and patient co-authored analysis of the lived experience of generalized myasthenia gravis, which may be applicable to other indications. We also assessed the quality of patient engagement throughout the research project. METHODS We used self-reported experience surveys based on the Patient Focused Medicines Development Patient Engagement Quality Guidance criteria for assessing patient engagement. The surveys were adapted to focus on individual projects and assessed eight domains using a five-point Likert scale. In September 2020, we invited eight patient council members to complete a self-reported experience survey following qualitative lived experience data generation. We calculated the average experience score as a percentage of the maximum possible score. Patient authors (n = 1) and non-patient authors (n = 3) were invited to complete a similar survey in November 2021, with questions customized for relevance, to evaluate the authorship experience following publication of the research. RESULTS Overall, patient council members had a positive experience of taking part in this study, with an average experience score of 90% (71.6/80.0; n = 8). The patient author and non-patient authors rated their authorship experience highly, with average experience scores of 92% (78.0/85.0) and 97% (63.3/65.0), respectively. There were key aspects that contributed to the overall project success (e.g., ensuring that all participants were aligned on the project objectives at the outset and understood their roles and responsibilities). We also identified elements of the approach that could be improved in future collaborations. CONCLUSION In this patient-led analysis, patient council members, patient authors and non-patient authors had a positive experience of being involved in the project. We gained useful insights into elements that contributed to the project's success and ways to improve future patient-led projects on the lived experience.
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Affiliation(s)
| | | | - Kelly Davio
- Patient Author, MG Patient Advocate, Richmond, London, UK
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Vergoossen DLE, Ruiter AM, Keene KR, Niks EH, Tannemaat MR, Strijbos E, Lipka AF, van der Zijde ECJ, van Tol MJD, Bakker JA, Wevers BA, Westerberg E, Borges LS, Tong OC, Richman DP, Illa I, Punga AR, Evoli A, van der Maarel SM, Verschuuren JJ, Huijbers MG. Enrichment of serum IgG4 in MuSK myasthenia gravis patients. J Neuroimmunol 2022; 373:577978. [PMID: 36240543 DOI: 10.1016/j.jneuroim.2022.577978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/26/2022] [Accepted: 10/05/2022] [Indexed: 11/05/2022]
Abstract
Muscle-specific kinase (MuSK) myasthenia gravis (MG) is a neuromuscular autoimmune disease belonging to a growing group of IgG4 autoimmune diseases (IgG4-AIDs), in which the majority of pathogenic autoantibodies are of the IgG4 subclass. The more prevalent form of MG with acetylcholine receptor (AChR) antibodies is caused by IgG1-3 autoantibodies. A dominant role for IgG4 in autoimmune disease is intriguing due to its anti-inflammatory characteristics. It is unclear why MuSK autoantibodies are predominantly IgG4. We hypothesized that MuSK MG patients have a general predisposition to generate IgG4 responses, therefore resulting in high levels of circulating IgG4. To investigate this, we quantified serum Ig isotypes and IgG subclasses using nephelometric and turbidimetric assays in MuSK MG and AChR MG patients not under influence of immunosuppressive treatment. Absolute serum IgG1 was increased in both MuSK and AChR MG patients compared to healthy donors. In addition, only MuSK MG patients on average had significantly increased and enriched serum IgG4. Although more MuSK MG patients had elevated serum IgG4, for most the IgG4 serum levels fell within the normal range. Correlation analyses suggest MuSK-specific antibodies do not solely explain the variation in IgG4 levels. In conclusion, although serum IgG4 levels are slightly increased, the levels do not support ubiquitous IgG4 responses in MuSK MG patients as the underlying cause of dominant IgG4 MuSK antibodies.
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Affiliation(s)
- Dana L E Vergoossen
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands
| | - Annabel M Ruiter
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Kevin R Keene
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Erik H Niks
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Ellen Strijbos
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Alexander F Lipka
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Els C Jol van der Zijde
- Willem-Alexander Children's Hospital, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maarten J D van Tol
- Willem-Alexander Children's Hospital, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Jaap A Bakker
- Department of Clinical Chemistry, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Brigitte A Wevers
- Department of Clinical Chemistry, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Elisabet Westerberg
- Clinical Neurophysiology, Department of Medical Sciences, Uppsala University, Akademiska sjukhuset, Ingång 85, 3rd floor, 751 85 Uppsala, Sweden
| | - Lúcia S Borges
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - Olivia C Tong
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - David P Richman
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - Isabel Illa
- Neuromuscular diseases Neurology department, Hospital Sant Pau UAB, Avenida Pare Claret N° 167, Barcelona 08025, Spain
| | - Anna Rostedt Punga
- Clinical Neurophysiology, Department of Medical Sciences, Uppsala University, Akademiska sjukhuset, Ingång 85, 3rd floor, 751 85 Uppsala, Sweden
| | - Amelia Evoli
- Department of Neurology, Università Cattolica del Sacro Cuore, Largo A. Gemelli 1, 00168 Rome, Italy
| | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands
| | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands; Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands.
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Keene KR, Kan HE, van der Meeren S, Verbist BM, Tannemaat MR, Beenakker JM, Verschuuren JJ. Clinical and imaging clues to the diagnosis and follow-up of ptosis and ophthalmoparesis. J Cachexia Sarcopenia Muscle 2022; 13:2820-2834. [PMID: 36172973 PMCID: PMC9745561 DOI: 10.1002/jcsm.13089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 12/15/2022] Open
Abstract
Ophthalmoparesis and ptosis can be caused by a wide range of rare or more prevalent diseases, several of which can be successfully treated. In this review, we provide clues to aid in the diagnosis of these diseases, based on the clinical symptoms, the involvement pattern and imaging features of extra-ocular muscles (EOM). Dysfunction of EOM including the levator palpebrae can be due to muscle weakness, anatomical restrictions or pathology affecting the innervation. A comprehensive literature review was performed to find clinical and imaging clues for the diagnosis and follow-up of ptosis and ophthalmoparesis. We used five patterns as a framework for differential diagnostic reasoning and for pattern recognition in symptomatology, EOM involvement and imaging results of individual patients. The five patterns were characterized by the presence of combination of ptosis, ophthalmoparesis, diplopia, pain, proptosis, nystagmus, extra-orbital symptoms, symmetry or fluctuations in symptoms. Each pattern was linked to anatomical locations and either hereditary or acquired diseases. Hereditary muscle diseases often lead to ophthalmoparesis without diplopia as a predominant feature, while in acquired eye muscle diseases ophthalmoparesis is often asymmetrical and can be accompanied by proptosis and pain. Fluctuation is a hallmark of an acquired synaptic disease like myasthenia gravis. Nystagmus is indicative of a central nervous system lesion. Second, specific EOM involvement patterns can also provide valuable diagnostic clues. In hereditary muscle diseases like chronic progressive external ophthalmoplegia (CPEO) and oculo-pharyngeal muscular dystrophy (OPMD) the superior rectus is often involved. In neuropathic disease, the pattern of involvement of the EOM can be linked to specific cranial nerves. In myasthenia gravis this pattern is variable within patients over time. Lastly, orbital imaging can aid in the diagnosis. Fat replacement of the EOM is commonly observed in hereditary myopathic diseases, such as CPEO. In contrast, inflammation and volume increases are often observed in acquired muscle diseases such as Graves' orbitopathy. In diseases with ophthalmoparesis and ptosis specific patterns of clinical symptoms, the EOM involvement pattern and orbital imaging provide valuable information for diagnosis and could prove valuable in the follow-up of disease progression and the understanding of disease pathophysiology.
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Affiliation(s)
- Kevin R. Keene
- CJ Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Department of NeurologyLeiden University Medical CenterLeidenThe Netherlands
| | - Hermien E. Kan
- CJ Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Duchenne CenterThe Netherlands
| | - Stijn van der Meeren
- Department of OphthalmologyLeiden University Medical CenterLeidenThe Netherlands
- Orbital Center, Department of OphthalmologyAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Berit M. Verbist
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | | | - Jan‐Willem M. Beenakker
- CJ Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Department of OphthalmologyLeiden University Medical CenterLeidenThe Netherlands
- Department of Radiation OncologyLeiden University Medical CenterLeidenThe Netherlands
| | - Jan J.G.M. Verschuuren
- Department of NeurologyLeiden University Medical CenterLeidenThe Netherlands
- Duchenne CenterThe Netherlands
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Mental health in myasthenia gravis patients and its impact on caregiver burden. Sci Rep 2022; 12:19275. [PMID: 36369246 PMCID: PMC9652470 DOI: 10.1038/s41598-022-22078-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Psychiatric comorbidities are relevant in patients with Myasthenia gravis (MG). Also, MG patients experience a reduced health-related quality of life (HRQoL). We aimed to quantify the impact of depression as well as self-perceived MG severity on HRQoL and caregivers' burden. In this cross-sectional study, we used a survey encompassing demographic, disease-related information, and standardized questionnaires to assess symptoms of depression, anxiety, HRQoL (MG Quality of Life scale; MG-QoL15), and caregiver burden (Burden Scale for Family Caregivers; BSFC). Data from 1399 participating patients (96%) and 1042 caregivers (65%) were eligible for further analysis. Symptoms of depression and anxiety disorder were indicated by 31% and 36% of patients. Self-reported MG severity (MG severity) and MG-QoL15 scores were strongly associated (estimated marginal means for severe versus mild MG severity = 18 95% CI [16; 21]; p ≤ 0.001). Adjusting for symptoms of depression decreased the estimated strength of this association (estimated marginal means for severe versus mild MG severity = 15 [13; 17]; p ≤ 0.001). Caregiver burden was associated to MG disease severity (estimated marginal means for severe vs. mild MG severity = 0.16 [0.13; 0,19); p ≤ 0.001) and also negatively influenced by symptoms of depression (estimated marginal means = 0.12 [0.09; 0.15]). Symptoms of depression and anxiety disorder in MG are frequent. Beyond MG severity, symptoms of depression have negative effects on HRQoL as well as on caregivers' burden. Diagnosis and treatment of psychiatric comorbidities should be considered an important element in MG care. Screening tools for mental health conditions should be implemented at least in specialized MG centers.
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Punga AR, Maddison P, Heckmann JM, Guptill JT, Evoli A. Epidemiology, diagnostics, and biomarkers of autoimmune neuromuscular junction disorders. Lancet Neurol 2022; 21:176-188. [DOI: 10.1016/s1474-4422(21)00297-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/18/2021] [Accepted: 08/25/2021] [Indexed: 12/14/2022]
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Li J, Qi G, Liu Y. Effect of Buzhong Yiqi decoction on anti-acetylcholine receptor antibody and clinical status in juvenile ocular myasthenia gravis. Medicine (Baltimore) 2021; 100:e27688. [PMID: 34871253 PMCID: PMC8568406 DOI: 10.1097/md.0000000000027688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/18/2021] [Indexed: 01/21/2023] Open
Abstract
Ocular myasthenia gravis (MG) is the mainly widespread type of MG among juveniles. Buzhong Yiqi decoction (BZ) is a well-known traditional Chinese medicine prescription for treating MG. It has rarely been discussed whether the concentration of anti-acetylcholine receptor (AChR) antibodies is related to the clinical status of juvenile ocular myasthenia gravis (JOMG) treated with BZ.The patients with JOMG who had more than once AChR-antibody (ab) test and treated with BZ were retrospectively identified from June 2013 to January 2020 in the first hospital in Shijiazhuang. The presence or absence of ocular symptoms was used to grade the effectiveness of treatment. Generalized estimating equations logistic regression analysis was used to evaluate the effect of AChR ab concentration on the clinical status of MG.A total of 549 AChR-ab tests were performed in 135 patients, and the corresponding clinical status was recorded. One hundred two patients received treatment with BZ only and 33 combined with immunosuppressive drugs. In the group receiving only BZ treatment, the anti-acetylcholine receptor ab concentration was positively correlated with the clinical score after treatment.The results suggest that BZ could affect the AChR-ab. Repeated AChR-ab assays can provide information about the clinical status. For JOMG patients who only receive Buzhong Yiqi Decoction treatment, this can support treatment decisions.
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Affiliation(s)
- Jiaduo Li
- Center of Treatment of Myasthenia Gravis, People‘s Hospital of Shijiazhuang Affiliated to Hebei Medical University, China
| | - Guoyan Qi
- Center of Treatment of Myasthenia Gravis, People‘s Hospital of Shijiazhuang Affiliated to Hebei Medical University, China
| | - Yaling Liu
- Gastroenterology Department, People‘s Hospital of Shijiazhuang Affiliated to Hebei Medical University, China
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Ruiter AM, Strijbos E, de Meel RHP, Lipka AF, Raadsheer WF, Tannemaat MR, Verschuuren JJGM. Accuracy of patient-reported data for an online patient registry of autoimmune myasthenia gravis and Lambert-Eaton myasthenic syndrome. Neuromuscul Disord 2021; 31:622-632. [PMID: 34210541 DOI: 10.1016/j.nmd.2021.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 05/17/2021] [Accepted: 05/20/2021] [Indexed: 11/18/2022]
Abstract
Disorders of the neuromuscular junction (NMJ) comprise a spectrum of rare diseases causing muscle fatigability and weakness, leading to life-long effects on quality of life. We established the Dutch-Belgian registry for NMJ disorders, based on a unique combination of patient- and physician-reported information. Information on natural course, disease burden, prevalence of complications and comorbidity is collected through patient-reported standardized questionnaires and verified using medical documentation. Currently, the registry contains information of 565 Myasthenia Gravis (MG) patients and 38 Lambert-Eaton myasthenic syndrome (LEMS) patients, constituting approximately 25% (MG) and 80% (LEMS) of patients in the Netherlands. This is a very large registry, with the highest participation rate per capita. In addition to confirming many disease characteristics previously described in the literature, this registry provides several novel insights. The reported rate of potentially corticosteroid-related comorbidity, including hypertension, heart disease, osteoporosis and type 2 diabetes was high, emphasizing the need to commence corticosteroid-sparing immune suppressive treatment as soon as possible. The reported rate of other auto-immune diseases is far higher than previously expected: 27% of MG and 38% of LEMS patients, and a surprisingly high number of MG patients (47%) is unaware of their antibody status. In conclusion, this registry provides a valuable collection of information regarding MG and LEMS disease course. Continuous collection of annual follow-up data will provide further longitudinal insights in disease burden, course and treatment effect.
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Affiliation(s)
- Annabel M Ruiter
- Department of Neurology, Leiden University Medical Center, the Netherlands.
| | - Ellen Strijbos
- Department of Neurology, Leiden University Medical Center, the Netherlands
| | - Robert H P de Meel
- Department of Neurology, Leiden University Medical Center, the Netherlands
| | - Alexander F Lipka
- Department of Neurology, Leiden University Medical Center, the Netherlands; Department of Neurology, Groene Hart Hospital, Gouda, the Netherlands
| | - Wouter F Raadsheer
- Department of Neurology, Leiden University Medical Center, the Netherlands
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Ruiter AM, Verschuuren JJGM, Tannemaat MR. Prevalence and associated factors of fatigue in autoimmune myasthenia gravis. Neuromuscul Disord 2021; 31:612-621. [PMID: 34034925 DOI: 10.1016/j.nmd.2021.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/06/2021] [Accepted: 04/11/2021] [Indexed: 12/13/2022]
Abstract
Fatigue is usually defined as a subjective perception of lacking energy, mentally or physically, with a difficulty sustaining voluntary activities. It is a common symptom of many diseases and most likely has a multifactorial cause. In myasthenia gravis (MG), fatigue has a high prevalence and is correlated with female sex and disease severity. However, no large scale studies have been performed. Therefore, we aimed to evaluate fatigue in the Dutch participants (n = 420) of the Dutch-Belgian Myasthenia Patient Registry using an online survey. Additional information was obtained on mood, sleep, coping, quality of life, disease severity, physical activities and medication. Severe fatigue was present in 62% with a mean score of 37.1 ± 13.2 points. Fatigue severity and prevalence increased significantly with disease severity. A positive correlation was found for female gender, BMI, disease severity and depressive symptoms. A negative correlation was found for strenuous physical activities and older age. The strong association with disease severity suggests that fatigue should be recognized as an element of the symptomatology of MG. The observed association between strenuous activity and fatigue and differences in coping style between fatigued and non-fatigued patients warrant future clinical trials on exercise and cognitive behavioral therapy.
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Affiliation(s)
- Annabel M Ruiter
- Department of Neurology, Leiden University Medical Center, the Netherlands.
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Ruiter AM, Verschuuren JJ, Tannemaat MR. Fatigue in patients with myasthenia gravis. A systematic review of the literature. Neuromuscul Disord 2020; 30:631-639. [DOI: 10.1016/j.nmd.2020.06.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/09/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022]
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Wang S, Breskovska I, Gandhy S, Punga AR, Guptill JT, Kaminski HJ. Advances in autoimmune myasthenia gravis management. Expert Rev Neurother 2018; 18:573-588. [PMID: 29932785 PMCID: PMC6289049 DOI: 10.1080/14737175.2018.1491310] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Myasthenia gravis (MG) is an autoimmune neuromuscular disorder with no cure and conventional treatments limited by significant adverse effects and variable benefit. In the last decade, therapeutic development has expanded based on improved understanding of autoimmunity and financial incentives for drug development in rare disease. Clinical subtypes exist based on age, gender, thymic pathology, autoantibody profile, and other poorly defined factors, such as genetics, complicate development of specific therapies. Areas covered: Clinical presentation and pathology vary considerably among patients with some having weakness limited to the ocular muscles and others having profound generalized weakness leading to respiratory insufficiency. MG is an antibody-mediated disorder dependent on autoreactive B cells which require T-cell support. Treatments focus on elimination of circulating autoantibodies or inhibition of effector mechanisms by a broad spectrum of approaches from plasmapheresis to B-cell elimination to complement inhibition. Expert commentary: Standard therapies and those under development are disease modifying and not curative. As a rare disease, clinical trials are challenged in patient recruitment. The great interest in development of treatments specific for MG is welcome, but decisions will need to be made to focus on those that offer significant benefits to patients.
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Affiliation(s)
- Shuhui Wang
- Department of Neurology, George Washington University, Washington DC 20008
| | - Iva Breskovska
- Department of Neurology, George Washington University, Washington DC 20008
| | - Shreya Gandhy
- Department of Neurology, George Washington University, Washington DC 20008
| | - Anna Rostedt Punga
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | - Jeffery T. Guptill
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - Henry J. Kaminski
- Department of Neurology, George Washington University, Washington DC 20008
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Zagoriti Z, Lagoumintzis G, Perroni G, Papathanasiou G, Papadakis A, Ambrogi V, Mineo TC, Tzartos JS, Poulas K. Evidence for association of STAT4 and IL12RB2 variants with Myasthenia gravis susceptibility: What is the effect on gene expression in thymus? J Neuroimmunol 2018; 319:93-99. [PMID: 29576322 DOI: 10.1016/j.jneuroim.2018.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease mediated by the presence of autoantibodies that bind mainly to the acetylcholine receptor (AChR) in the neuromuscular junction. In our case-control association study, we analyzed common variants located in genes of the IL12/STAT4 and IL10/STAT3 signaling pathways. A total of 175 sporadic MG patients of Greek descent, positively detected with anti-AChR autoantibodies and 84 ethnically-matched, healthy volunteers were enrolled in the study. Thymus samples were obtained from 16 non-MG individuals for relative gene expression analysis. The strongest signals of association were observed in the cases of rs6679356 between the late-onset MG patients and controls and rs7574865 between early-onset MG and controls. Our investigation of the correlation between the MG-associated variants and the expression levels of each gene in thymus did not result in significant differences.
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Affiliation(s)
- Zoi Zagoriti
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, University Campus, Rio, 26504 Patras, Greece.
| | - George Lagoumintzis
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, University Campus, Rio, 26504 Patras, Greece
| | - Gianluca Perroni
- Department of Surgery and Experimental Medicine, Tor Vergata University, Rome, Italy
| | - George Papathanasiou
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, University Campus, Rio, 26504 Patras, Greece
| | - Andreas Papadakis
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, University Campus, Rio, 26504 Patras, Greece
| | - Vincenzo Ambrogi
- Department of Surgery and Experimental Medicine, Tor Vergata University, Rome, Italy
| | - Tommaso Claudio Mineo
- Department of Surgery and Experimental Medicine, Tor Vergata University, Rome, Italy
| | - John S Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521 Athens, Greece; Tzartos NeuroDiagnostics, 3, Eslin street, Athens 115 23, Greece
| | - Konstantinos Poulas
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, University Campus, Rio, 26504 Patras, Greece.
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Qi G, Liu P, Gu S, Yang H, Dong H, Xue Y. Whole-exome sequencing reveals a rare interferon gamma receptor 1 mutation associated with myasthenia gravis. Neurol Sci 2018; 39:717-724. [PMID: 29441481 DOI: 10.1007/s10072-018-3275-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 02/02/2018] [Indexed: 10/18/2022]
Abstract
Our study is aimed to explore the underlying genetic basis of myasthenia gravis. We collected a Chinese pedigree with myasthenia gravis, and whole-exome sequencing was performed on the two affected siblings and their parents. The candidate pathogenic gene was identified by bioinformatics filtering, which was further verified by Sanger sequencing. The homozygous mutation c.G40A (p.V14M) in interferon gamma receptor 1was identified. Moreover, the mutation was also detected in 3 cases of 44 sporadic myasthenia gravis patients. The p.V14M substitution in interferon gamma receptor 1 may affect the signal peptide function and the translocation on cell membrane, which could disrupt the binding of the ligand of interferon gamma and antibody production, contributing to myasthenia gravis susceptibility. We discovered that a rare variant c.G40A in interferon gamma receptor 1 potentially contributes to the myasthenia gravis pathogenesis. Further functional studies are needed to confirm the effect of the interferon gamma receptor 1 on the myasthenia gravis phenotype.
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Affiliation(s)
- Guoyan Qi
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China.
| | - Peng Liu
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China
| | - Shanshan Gu
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China
| | - Hongxia Yang
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China
| | - Huimin Dong
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China
| | - Yinping Xue
- Center of Treatment of Myasthenia Gravis Hebei Province, First Hospital of Shijiazhuang, Fangbei road No. 9, Shijiazhuang, Hebei Province, 050011, China
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Kubiszewska J, Szyluk B, Szczudlik P, Bartoszewicz Z, Dutkiewicz M, Bielecki M, Bednarczuk T, Kostera-Pruszczyk A. Prevalence and impact of autoimmune thyroid disease on myasthenia gravis course. Brain Behav 2016; 6:e00537. [PMID: 27781146 PMCID: PMC5064344 DOI: 10.1002/brb3.537] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/12/2016] [Accepted: 06/21/2016] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Autoimmune thyroid diseases (ATDs) frequently accompany myasthenia gravis (MG) and may influence its course. We aimed to determine the association and impact of ATD with early- (<50 years), late-onset MG, or thymoma-MG. MATERIALS AND METHODS Prevalence of ATD was measured in a cross-sectional study of 343 consecutive patients with MG (236 F, 107 M) aged 4-89 years; 83.8% were seropositive, in 2.9%, anti-MuSK antibodies were detected. Concentrations of antithyroid peroxidase antibodies, antithyroglobulin antibodies, antithyrotropin receptor antibodies, and TSH level were measured in all patients. MG clinical course, treatment received, and treatment results were evaluated. RESULTS Autoimmune thyroid diseases were diagnosed in 92 (26.8%) of MG patients including 4.4% with Graves (GD), 9% with Hashimoto thyroiditis (HT), and 13.4% with antithyroid antibodies only. GD patients had ocular symptoms more often than patients with antithyroid antibodies or HT (p = .008). ATD prevalence was comparable in MG with early and late onset, while non-ATDs were more frequent in thymoma-MG (p = .049). Immunosuppressive therapy was less frequently needed in the patients with MG and ATD, indirectly indicating milder MG course (p = .005). Risk of myasthenic crisis and the results of treatment did not differ between patients with and without ATD. CONCLUSIONS Autoimmune thyroid diseases are frequently accompanied by early-and late-onset MG, while thymoma-MG is related to higher risk of non-ATD. Myasthenia coexisting with ATD follows milder course than MG alone.
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Affiliation(s)
| | - Beata Szyluk
- Department of Neurology Medical University of Warsaw Warsaw Poland
| | - Piotr Szczudlik
- Department of Neurology Medical University of Warsaw Warsaw Poland
| | - Zbigniew Bartoszewicz
- Department of Internal Medicine and Endocrinology Medical University of Warsaw Warsaw Poland
| | - Małgorzata Dutkiewicz
- Department of Immunology, Biochemistry and Nutrition Medical University of Warsaw Warsaw Poland
| | - Maksymilian Bielecki
- Department of Psychology SWPS University of Social Sciences and Humanities Warsaw Poland
| | - Tomasz Bednarczuk
- Department of Internal Medicine and Endocrinology Medical University of Warsaw Warsaw Poland
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Nacu A, Andersen JB, Lisnic V, Owe JF, Gilhus NE. Complicating autoimmune diseases in myasthenia gravis: a review. Autoimmunity 2015; 48:362-8. [PMID: 25915571 PMCID: PMC4616023 DOI: 10.3109/08916934.2015.1030614] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Myasthenia gravis (MG) is a rare autoimmune disease of skeletal muscle endplates. MG subgroup is relevant for comorbidity, but usually not accounted for. MG patients have an increased risk for complicating autoimmune diseases, most commonly autoimmune thyroid disease, systemic lupus erythematosus and rheumatoid arthritis. In this review, we present concomitant autoimmune disorders associated with the different MG subgroups, and show how this influences treatment and prognosis. Concomitant MG should always be considered in patients with an autoimmune disorder and developing new neuromuscular weakness, fatigue or respiratory failure. When a second autoimmune disorder is suspected, MG should be included as a differential diagnosis.
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Affiliation(s)
- Aliona Nacu
- a Department of Neurology , Haukeland University Hospital , Bergen , Norway
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17
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Heldal AT, Eide GE, Romi F, Owe JF, Gilhus NE. Repeated acetylcholine receptor antibody-concentrations and association to clinical myasthenia gravis development. PLoS One 2014; 9:e114060. [PMID: 25464006 PMCID: PMC4252099 DOI: 10.1371/journal.pone.0114060] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 11/03/2014] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION We aimed to examine the longitudinal association between Myasthenia Gravis (MG) clinical severity and concentration of acetylcholine receptor (AChR)-antibodies to evaluate if AChR-antibody variations correlate to disease severity. A positive AChR-antibody test is specific for MG. MATERIAL AND METHODS All patients from western Norway who had two or more AChR- antibody tests in the period 1983-2013 were identified. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification was used to grade disease development. Multiple ordinal logistic regression analysis was used to estimate a possible predictive effect for AChR-antibody concentration on MGFA classification result. RESULTS In 67 patients two or more AChR-antibody tests with a corresponding MGFA-score were performed, with a total of 309 tests. 56 patients were treated with immunosuppressive drugs and 11 by pyridostigmine only. There was a positive association between concentration of AChR-antibodies and longitudinal MGFA-score for the subgroup with immunosuppressive treatment, but not for those treated with pyridostigmine only. This association between AChR-antibody concentration and MGFA score declined with increasing time since onset (p = 0.005 for the interaction of group×time×concentration). CONCLUSIONS For MG patients with immunosuppressive treatment, repeated AChR-antibody measurements give information about clinical development, and can therefore be of support in therapeutic decisions.
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Affiliation(s)
| | - Geir Egil Eide
- Centre of Clinical Research, Haukeland University Hospital, Bergen, Norway
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Fredrik Romi
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Jone Furlund Owe
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Nils Erik Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
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Parr JR, Andrew MJ, Finnis M, Beeson D, Vincent A, Jayawant S. How common is childhood myasthenia? The UK incidence and prevalence of autoimmune and congenital myasthenia. Arch Dis Child 2014; 99:539-42. [PMID: 24500997 DOI: 10.1136/archdischild-2013-304788] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To ascertain the frequency of childhood myasthenia in the UK. Specifically, we aimed to identify the detected incidence of autoimmune myasthenia and the detected prevalence of genetically confirmed congenital myasthenic syndrome (CMS) in children. METHODS All children under 18 years of age on 31 December 2009 with a confirmed CMS genetic mutation were identified by the only UK laboratory undertaking CMS genetic testing. All cases with positive acetylcholine receptor (AChR) and muscle specific kinase (MuSK) receptor antibodies in the 5 years between 2003 and 2007 inclusive were identified by the testing laboratories. UK census data from 2001 were used as the denominator for analyses. RESULTS The UK detected prevalence of genetically confirmed CMS was 9.2 per million children under 18 years of age. CMS was equally prevalent in girls and boys. CHRNE, RAPSN and DOK7 were the most commonly identified mutations. Prevalence varied across geographical regions in England (between 2.8 and 14.8 per million children). The mean incidence of antibody-positive autoimmune myasthenia was 1.5 per million children per year over the period of the study. Girls were affected more frequently than boys; this difference persisted across the age range. Antibodies were identified during the neonatal period in 17 children. CONCLUSIONS This laboratory based study shows that childhood myasthenia is very rare. This condition is treatable, and these definitive detected incidence and prevalence data can be used to help plan diagnostic and supporting services for affected children and their families, and maximise research opportunities.
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Affiliation(s)
- Jeremy Ross Parr
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK Department of Paediatrics, University of Oxford, Oxford, UK
| | | | - Maria Finnis
- Department of Paediatrics, University of Oxford, Oxford, UK
| | - David Beeson
- The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Angela Vincent
- The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Zagoriti Z, Kambouris ME, Patrinos GP, Tzartos SJ, Poulas K. Recent advances in genetic predisposition of myasthenia gravis. BIOMED RESEARCH INTERNATIONAL 2013; 2013:404053. [PMID: 24294607 PMCID: PMC3835684 DOI: 10.1155/2013/404053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 09/11/2013] [Indexed: 01/04/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune disease mediated by the presence of autoantibodies that bind to components of the neuromuscular junction, causing the symptoms of muscular weakness and fatigability. Like most autoimmune disorders, MG is a multifactorial, noninherited disease, though with an established genetic constituent. The heterogeneity observed in MG perplexes genetic analysis even more, as it occurs in various levels, including diverse autoantigens, thymus histopathology, and age at onset. In this context of distinct subgroups, a plethora of association studies, discussed in this review, have assessed the involvement of various HLA and non-HLA related loci in MG susceptibility, over the past five years. As expected, certain HLA alleles were strongly associated with MG. Many of the non-HLA genes, such as PTPN22 and CTLA-4, have been previously studied in MG and other autoimmune diseases and their association with MG has been reevaluated in more cohesive groups of patients. Moreover, novel risk or protective loci have been revealed, as in the case of TNIP1 and FOXP3. Although the majority of these results have been derived from candidate gene studies, the focal point of all recent genetic studies is the first genome-wide association study (GWAS) conducted on early-onset MG patients.
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Affiliation(s)
- Zoi Zagoriti
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio, Patras, Greece
| | - Manousos E. Kambouris
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio, Patras, Greece
| | - George P. Patrinos
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio, Patras, Greece
| | - Socrates J. Tzartos
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio, Patras, Greece
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vas. Sofias Avenue, 11521 Athens, Greece
| | - Konstantinos Poulas
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio, Patras, Greece
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Zisimopoulou P, Brenner T, Trakas N, Tzartos SJ. Serological diagnostics in myasthenia gravis based on novel assays and recently identified antigens. Autoimmun Rev 2013; 12:924-30. [PMID: 23537507 DOI: 10.1016/j.autrev.2013.03.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
Abstract
Myasthenia gravis (MG) is the most common immune-mediated disorder of the neuromuscular junction with a prevalence of 200-300/million population and its study has established paradigms for exploring other antibody-mediated diseases. Most MG patients (~85%) have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 6% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). Until recently no autoantibodies could be detected in the remaining patients (seronegative MG). Probably, the most sensitive assays for the detection of the autoantibodies in MG sera have been the radioimmunoprecipitation assays (RIPA) for both types of MG. However, with recent novel methods, not yet used routinely, it has been shown that the "seronegative" MG group includes patients with low levels of autoantibodies or of low affinity, against the known autoantigens, or even with antibodies to recently identified autoantigens. Since MG is heterogeneous in terms of pathophysiology, depending on the autoantigen targeted and on other factors (e.g. presence of thymoma), the serological tests are crucial in verifying the initial clinical diagnosis, whereas frequent measurement of autoantibody levels is important in monitoring the course of the disease and the efficacy of treatment. In addition, in AChR-MG, autoantibodies against the muscle proteins titin and ryanodin receptor have been identified; these antibodies are useful for the classification of MG, indicating the concomitant presence of thymoma, and as prognostic markers.
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21
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Plomp JJ, Huijbers MG, van der Maarel SM, Verschuuren JJ. Pathogenic IgG4 subclass autoantibodies in MuSK myasthenia gravis. Ann N Y Acad Sci 2012; 1275:114-22. [DOI: 10.1111/j.1749-6632.2012.06808.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Klooster R, Plomp JJ, Huijbers MG, Niks EH, Straasheijm KR, Detmers FJ, Hermans PW, Sleijpen K, Verrips A, Losen M, Martinez-Martinez P, De Baets MH, van der Maarel SM, Verschuuren JJ. Muscle-specific kinase myasthenia gravis IgG4 autoantibodies cause severe neuromuscular junction dysfunction in mice. Brain 2012; 135:1081-101. [DOI: 10.1093/brain/aws025] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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23
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Pal J, Rozsa C, Komoly S, Illes Z. Clinical and biological heterogeneity of autoimmune myasthenia gravis. J Neuroimmunol 2011; 231:43-54. [DOI: 10.1016/j.jneuroim.2010.10.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Vrolix K, Fraussen J, Molenaar PC, Losen M, Somers V, Stinissen P, De Baets MH, Martínez-Martínez P. The auto-antigen repertoire in myasthenia gravis. Autoimmunity 2010; 43:380-400. [PMID: 20380581 DOI: 10.3109/08916930903518073] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myasthenia Gravis (MG) is an antibody-mediated autoimmune disorder affecting the postsynaptic membrane of the neuromuscular junction (NMJ). MG is characterized by an impaired signal transmission between the motor neuron and the skeletal muscle cell, caused by auto-antibodies directed against NMJ proteins. The auto-antibodies target the nicotinic acetylcholine receptor (nAChR) in about 90% of MG patients. In approximately 5% of MG patients, the muscle specific kinase (MuSK) is the auto-antigen. In the remaining 5% of MG patients, however, antibodies against the nAChR or MuSK are not detectable (idiopathic MG, iMG). Although only the anti-nAChR and anti-MuSK auto-antibodies have been demonstrated to be pathogenic, several other antibodies recognizing self-antigens can also be found in MG patients. Various auto-antibodies associated with thymic abnormalities have been reported, as well as many non-MG-specific auto-antibodies. However, their contribution to the cause, pathology and severity of the disease is still poorly understood. Here, we comprehensively review the reported auto-antibodies in MG patients and discuss their role in the pathology of this autoimmune disease.
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Affiliation(s)
- Kathleen Vrolix
- Division of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
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