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myasthenic syndrome

Hiroyuki Fukuda, Akira Tanaka, Yasuyuki Hirashima, Ichiro Ito
Lambert-Eaton myasthenic syndrome (LEMS) is most commonly associated with small cell lung carcinoma, while it is rarely associated with gynecological and breast carcinoma. We herein report a case of LEMS associated with synchronous double cancer, which was a combination of small cell carcinoma of the cervix and breast carcinoma. The early diagnosis and treatment of LEMS are important for achieving a good outcome. The possibility of accompanying paraneoplastic neurological syndrome must be sufficiently considered in gynecology and breast cancer patients...
March 9, 2018: Internal Medicine
Kee Hong Park, Patrick Waters, Mark Woodhall, Bethan Lang, Thomas Smith, Jung-Joon Sung, Kwang-Kuk Kim, Young-Min Lim, Jee-Eun Kim, Byung-Jo Kim, Jin-Sung Park, Jeong-Geon Lim, Dae-Seong Kim, Ohyun Kwon, Eun Hee Sohn, Jong Seok Bae, Byung-Nam Yoon, Nam-Hee Kim, Suk-Won Ahn, Jeeyoung Oh, Hyung Jun Park, Kyong Jin Shin, Yoon-Ho Hong
Acquired myasthenia gravis (MG) is a prototype autoimmune disease of the neuromuscular junction, caused in most patients by autoantibodies to the muscle nicotinic acetylcholine receptor (AChR). There seem to be ethnic and regional differences in the frequency and clinical features of MG seronegative for the AChR antibody. This study aimed to describe the autoantibody profiles and clinical features of Korean patients with generalized MG seronegative for the AChR antibody. A total of 62 patients with a high index of clinical suspicion of seronegative generalized MG were identified from 18 centers, and we examined their sera for antibodies to clustered AChR, muscle-specific tyrosine kinase (MuSK), and low-density lipoprotein receptor-related protein 4 (LRP4) by cell-based assays (CBA) and to MuSK by radioimmunoprecipitation assay (RIPA)...
2018: PloS One
Nakul Katyal, Raghav Govindarajan
Pure ocular presentation of Lambert-Eaton syndrome is not a common phenomenon. Such presentation poses significant diagnostic challenges and requires conscientious evaluation. In this review, we have described a case of a patient with pure ocular weakness, initially diagnosed as seronegative ocular myasthenia which on further evaluation was found to have ocular Lambert-Eaton myasthenic syndrome (LEMS).
December 31, 2017: Curēus
Jaimee A Domville, John E Baenziger
The mechanisms underlying lipid-sensing by membrane proteins is of considerable biological importance. A unifying mechanistic question is how a change in structure at the lipid-protein interface is translated through the transmembrane domain to influence structures critical to protein function. Gating of the nicotinic acetylcholine receptor (nAChR) is sensitive to its lipid environment. To understand how changes at the lipid-protein interface influence gating, we examined how a mutation at position 418 on the lipid-facing surface of the outer most M4 transmembrane α-helix alters the energetic couplings between M4 and the remainder of the transmembrane domain...
March 1, 2018: Scientific Reports
Paulo José Lorenzoni, Cláudia Suemi Kamoi Kay, Lineu Cesar Werneck, Rosana Herminia Scola
This historical review describes the contribution of Drs. Lee M. Eaton and Edward H. Lambert to the diagnosis of myasthenic syndrome on the 60th anniversary of their pioneering article (JAMA 1957) on the disease. There are important landmarks in their article on a disorder of the neuromuscular junction associated with thoracic neoplasm and the electrophysiological criteria for Lambert-Eaton myasthenic syndrome (LEMS). After 60 years, the main electrophysiological criteria described in Eaton and Lambert's pioneering article are still currently useful in the diagnosis of LEMS...
February 2018: Arquivos de Neuro-psiquiatria
Serkan Kırık, Olcay Güngör, Sedat Işıkay, Can Acıpayam, Yasemin Çoban, Emre Çelik
Decreased height of the eyelid or the narrowing of the lid is called ptosis. Ptosis has several causes. Malignancy-related conditions such as Horner's syndrome, which causes unilateral ptosis in the pediatric age group, and patients with malignancy receiving chemotherapeutic treatment, are often secondary to these drugs and ptosis is a clue of underlying diseases. Underlying pathologies can lead to different clinical conditions such as cognitive impairment from coma, the presence of ptosis should be cautionary...
December 2017: Türk Pediatri Arşivi
Sebastian Silva, Noriko Miyake, Carolina Tapia, Naomichi Matsumoto
Prolyl endopeptidase-like (PREPL) deficiency (MIM# 616224) is a rare autosomal recessive inherited congenital myasthenic syndrome characterized by neonatal hypotonia, feeding problems, mild dysmorphism, and neuromuscular symptoms, followed by hyperphagia and obesity in later childhood. Some patients also exhibit growth deficits, sexual hormone deficiency, and cognitive impairments. This syndrome is caused by biallelic mutations in PREPL. To date, only one nucleotide deletion and seven small microdeletions in PREPL have been reported...
February 26, 2018: Journal of Human Genetics
Andrew G Engel
The congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is compromised by one or more specific mechanisms. The disease proteins reside in the nerve terminal, the synaptic basal lamina, or in the postsynaptic region, or at multiple sites at the neuromuscular junction as well as in other tissues. Targeted mutation analysis by Sanger or exome sequencing has been facilitated by characteristic phenotypic features of some CMS. No fewer than 20 disease genes have been recognized to date...
2018: Handbook of Clinical Neurology
Mikako Ito, Kinji Ohno
Endplate acetylcholinesterase (AChE) deficiency is a form of congenital myasthenic syndrome (CMS) caused by mutations in COLQ, which encodes collagen Q (ColQ). ColQ is an extracellular matrix (ECM) protein that anchors AChE to the synaptic basal lamina. Biglycan, encoded by BGN, is another ECM protein that binds to the dystrophin-associated protein complex (DAPC) on skeletal muscle, which links the actin cytoskeleton and ECM proteins to stabilize the sarcolemma during repeated muscle contractions. Upregulation of biglycan stabilizes the DPAC...
February 20, 2018: Matrix Biology: Journal of the International Society for Matrix Biology
Matthew Pitt
The function of the neuromuscular junction in children is amenable to electrophysiological testing. Of the two tests available, repetitive nerve stimulation is uncomfortable and has a reduced sensitivity compared with single-fibre methodology. The latter is the method of choice, recording the variability in neuromuscular transmission as a value called jitter. It can be performed by voluntary activation of the muscle being examined, which is not suitable in children, or by stimulation techniques. A modification of these techniques, called Stimulated Potential Analysis with Concentric needle Electrodes (SPACE), is well tolerated and can be performed while the child is awake...
February 22, 2018: International Journal of Molecular Sciences
Grace McMacken, Dan Cox, Andreas Roos, Juliane Müller, Roger Whittaker, Hanns Lochmüller
Inherited defects of the neuromuscular junction (NMJ) comprise an increasingly diverse range of disorders, termed congenital myasthenic syndromes (CMS). Therapies acting on the sympathetic nervous system, including the selective β2 adrenergic agonist salbutamol and the α and β adrenergic agonist ephedrine, have become standard treatment for several types of CMS. However, the mechanism of the therapeutic effect of sympathomimetics in these disorders is not understood. Here, we examined the effect of salbutamol on NMJ development using zebrafish with deficiency of the key postsynaptic proteins Dok-7 and MuSK...
February 16, 2018: Human Molecular Genetics
Emily O'Connor, Vietxuan Phan, Isabell Cordts, George Cairns, Stefan Hettwer, Daniel Cox, Hanns Lochmüller, Andreas Roos
Congenital myasthenic syndromes (CMS) are a group of rare, inherited disorders characterised by compromised function of the neuromuscular junction, manifesting with fatigable muscle weakness. Mutations in MYO9A were previously identified as causative for CMS but the precise pathomechanism remained to be characterised. Based on the role of MYO9A as an actin-based molecular motor and as a negative regulator of RhoA, we hypothesised that loss of MYO9A may affect the neuronal cytoskeleton, leading to impaired intracellular transport...
February 16, 2018: Human Molecular Genetics
Ricardo A Maselli, Jessica Vázquez, Leah Schrumpf, Juan Arredondo, Marian Lara, Jonathan B Strober, Peter Pytel, Robert L Wollmann, Michael Ferns
BACKGROUND: Monogenic defects of synaptic vesicle (SV) homeostasis have been implicated in many neurologic diseases, including autism, epilepsy, and movement disorders. In addition, abnormal vesicle exocytosis has been associated with several endocrine dysfunctions. METHODS: We report an 11 year old girl with learning disabilities, tremors, ataxia, transient hyperglycemia, and muscle fatigability responsive to albuterol sulfate. Failure of neuromuscular transmission was confirmed by single fiber electromyography...
February 14, 2018: Molecular Genetics & Genomic Medicine
Claire Legay
The neuromuscular junction (NMJ) is a cholinergic synapse in vertebrates. This synapse connects motoneurons to muscles and is responsible for muscle contraction, a physiological process that is essential for survival. A key factor for the normal functioning of this synapse is the regulation of acetylcholine (ACh) levels in the synaptic cleft. This is ensured by acetylcholinesterase (AChE), which degrades ACh. A number of mutations in synaptic genes expressed in motoneurons or muscle cells have been identified and are causative for a class of neuromuscular diseases called congenital myasthenic syndromes (CMSs)...
February 2018: Annals of the New York Academy of Sciences
Moon Kyu Lee, Il Nam Sunwoo, Seung Min Kim
3,4-Diaminopyridine (34DAP) is a presynaptic transmission enhancer. Its efficacy for Lambert-Eaton myasthenic syndrome (LEMS) and myasthenia gravis (MG) was demonstrated. However, there are cases sharing the characteristics of both disease and the effect of 34DAP in "gray zone" patients is sparse. Recently, we prescribed 34DAP to five anti-acetylcholine receptor antibody-positive MG patients with electrophysiological LEMS patterns and three LEMS patients, and carefully monitored the responses. Sero-positive MG patients exhibited more favorable responses than LEMS patients...
February 2, 2018: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Hacer Durmus, Xin-Ming Shen, Piraye Serdaroglu-Oflazer, Bulent Kara, Yesim Parman-Gulsen, Coskun Ozdemir, Joan Brengman, Feza Deymeer, Andrew G Engel
Congenital myasthenic syndromes (CMS) are a group of hereditary disorders affecting the neuromuscular junction. Here, we present clinical, electrophysiological and genetic findings of 69 patients from 51 unrelated kinships from Turkey. Genetic tests of 60 patients were performed at Mayo Clinic. Median follow-up time was 9.8 years (range 1-22 years). The most common CMS was primary acetylcholine receptor (AChR) deficiency (31/51) and the most common mutations in AChR were c.1219 + 2T > G (12/51) and c...
November 28, 2017: Neuromuscular Disorders: NMD
Mariana Santos, Simão Cruz, João Peres, Luís Santos, Purificação Tavares, Jorge Pinto Basto, Vasco Salgado, Ana Herrero Valverde
DOK7 congenital myasthenic syndrome (DOK7-CMS) generally presents early in life and is treated with salbutamol or ephedrine. This report describes an atypical case of a 39-year-old woman who presented with proximal upper limb weakness in the third trimester of pregnancy and was initially diagnosed with seronegative myasthenia gravis. Dramatic clinical worsening under pyridostigmine and further inefficacy of steroids, intravenous human immunoglobulin (IVIG) and plasma exchange (PLEX) led to the presumptive diagnosis of a CMS...
December 13, 2017: Neuromuscular Disorders: NMD
Christophoros Astaras, Rita de Micheli, Bianca Moura, Thomas Hundsberger, Andreas F Hottinger
PURPOSE OF REVIEW: Immune checkpoint inhibitors represent a major step forward in the field of oncologic immunotherapy these last years and have significantly increased survival of cancer patients in an ever-growing number of indications. These agents block specific immune checkpoint molecules (programmed cell death protein 1 and its ligand as well as cytotoxic T-lymphocyte-associated antigen 4) that normally downregulate the immune response. These new agents show a specific range of adverse effects induced by abnormal immunologic activation...
February 1, 2018: Current Neurology and Neuroscience Reports
Huiru Feng, Hongyu Zhou
INTRODUCTION: Congenital myasthenic syndromes (CMS) are a group of genetic disorders that stem mostly from molecular defects in nicotinic acetylcholine receptors (AChRs). Defects in the cholinergic receptor nicotinic delta subunit (CHRND) gene can cause a series of myasthenic syndromes. Here, we report 2 new compound heterozygous variants of the CHRND gene in a Chinese male with CMS. CASE PRESENTATION: A 43-year-old Chinese male presented with progressive muscle weakness, difficulty chewing, and an inability to lift his head from the time he was 8 years old...
December 2017: Medicine (Baltimore)
Ryoji Naganuma, Ichiro Yabe, Ikuko Takahashi, Masaaki Matsushima, Takahiro Kano, Hidenao Sasaki
In this independent clinical study, we analyzed retrospectively the clinical features of 9 cases (6 male and 3 female) of Lambert-Eaton myasthenic syndrome that were administered 3,4-diaminopyridine (3,4-DAP). Four cases showed no cancer and 5 cases had small cell lung carcinoma. Seven cases were positive for anti voltage-gated calcium channel antibodies. Activities of daily living (ADL) were improved by 3,4-DAP in 8 cases that showed mainly weakness of the extremities, but did not improve ADL in 1 case with cerebellar ataxia of paraneoplastic cerebellar degeneration (PCD)...
January 31, 2018: Rinshō Shinkeigaku, Clinical Neurology
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