scholarly journals The Role of Mutations on HLA Genes in Lambert-Eaton Myasthenic Syndrome

2021 ◽  
Vol 10 (1) ◽  
pp. 01-06
Shahin Asadi ◽  
Mahsa Hemati ◽  
Naser Shagerdi Esmaeli

Lambert-Eaton myasthenic syndrome (LEMS) is a rare presynaptic disorder of neuromuscular transmission in which quantal release of acetylcholine (ACh) is impaired, causing a unique set of clinical characteristics, which include proximal muscle weakness, depressed tendon reflexes, posttetanic potentiation, and autonomic changes. [1] The initial presentation can be similar to that of myasthenia gravis (MG), but the progressions of the 2 diseases have some important differences. LEMS disrupts the normally reliable neurotransmission at the neuromuscular junction (NMJ). This disruption is thought to result from an autoantibody-mediated removal of a subset of the P/Q-type Ca2+ channels involved with neurotransmitter release.

2020 ◽  
Vol 43 (3) ◽  
pp. 183-187
Maria Kibtiar ◽  
Roksana Parvin ◽  
Manik Kumar Talukder ◽  
Choudhury Ali Kawser

Spinal muscular atrophy (SMA) type 3 is a relatively stable genetically determined chronic neuromuscular disorder caused by degeneration of motor neurons of spinal cord. Patients with type 3 SMA may gradually experience decline in muscle strength and motor function. However functional progression is difficult to document and mechanisms remain poorly understood. A five years old boy presented with proximal muscle weakness, generalized hypotonia, absent deep tendon reflexes and features of neuropathy and labeled as SMA type 3. Bangladesh J Child Health 2019; VOL 43 (3) :183-187

Development ◽  
2021 ◽  
Vol 148 (17) ◽  
Mohammad I. K. Hamad ◽  
Petya Petrova ◽  
Solieman Daoud ◽  
Obada Rabaya ◽  
Abdalrahim Jbara ◽  

ABSTRACT Reelin is a large secreted glycoprotein that regulates neuronal migration, lamination and establishment of dendritic architecture in the embryonic brain. Reelin expression switches postnatally from Cajal-Retzius cells to interneurons. However, reelin function in interneuron development is still poorly understood. Here, we have investigated the role of reelin in interneuron development in the postnatal neocortex. To preclude early cortical migration defects caused by reelin deficiency, we employed a conditional reelin knockout (RelncKO) mouse to induce postnatal reelin deficiency. Induced reelin deficiency caused dendritic hypertrophy in distal dendritic segments of neuropeptide Y-positive (NPY+) and calretinin-positive (Calr+) interneurons, and in proximal dendritic segments of parvalbumin-positive (Parv+) interneurons. Chronic recombinant Reelin treatment rescued dendritic hypertrophy in Relncko interneurons. Moreover, we provide evidence that RelncKO interneuron hypertrophy is due to presynaptic GABABR dysfunction. Thus, GABABRs in RelncKO interneurons were unable to block N-type (Cav2.2) Ca2+ channels that control neurotransmitter release. Consequently, the excessive Ca2+ influx through AMPA receptors, but not NMDA receptors, caused interneuron dendritic hypertrophy. These findings suggest that reelin acts as a ‘stop-growth-signal’ for postnatal interneuron maturation.

2021 ◽  
Vol 14 ◽  
pp. 2632010X2110517
Pamela Hernandez-Arriaga ◽  
Mauricio Gonzalez-Urquijo ◽  
Daniel Fernando López Altamirano ◽  
Bryan Vaca-Cartagena ◽  
Andres Vergil-Vargas ◽  

Lambert-Eaton syndrome is a rare paraneoplastic disorder of the neuromuscular junction, characterized by impaired release of acetylcholine, which causes proximal muscle weakness, depressed tendon reflexes, and autonomic changes. Most cases of Lambert-Eaton syndrome present in small-cell lung carcinoma, and only a few cases have been reported in other lung subtypes. Herein, we report a case of 69 years old male patient with Lambert-Eaton syndrome as a rare association with a pulmonary large-cell neuroendocrine carcinoma, which presented 5 months before neoplasm diagnosis. A lobectomy was auspiciously performed. A review of the literature is also presented.

2021 ◽  
Icaro França Navarro Pinto ◽  
Wladimir Bocca Vieira de Rezende Pinto ◽  
Igor Braga Farias ◽  
Bruno de Mattos Lombardi Badia ◽  
Gustavo Carvalho Costa ◽  

Introduction: Lambert-Eaton Myasthenic Syndrome (LEMS) is an ultrarare autoimmune disorder of neuromuscular junction characterized by proximal muscle weakness, arreflexia and autonomic dysfunction due to presynaptic dysfunction caused by autoantibodies against the P/Q-type voltagegated calcium channel with diminished release of acetylcholine. LEMS can occurs as a primary autoimmune disorder or as paraneoplastic disorder with more than half of LEMS cases associated with small cell lung cancer. Objectives: The main objective of this study is described clinical, epidemiological, serological, and neurophysiological findings of a Brazilian cohort with definitive diagnosis of Lambert-Eaton Myasthenic Syndrome (LEMS). Results We identified eight patients with definitive LEMS with a 2:1 male/ female prevalence, all present with proximal muscle weakness with lower limb predominance and the most common autonomic dysfunction were xeropthalmia in 100% of patients, orthostatic hypotension presented in 6 of 9 patients and erectile dysfunction in all male patients. Conclusions: LEMS should always be suspected in patients with proximal muscle weakness associated with autonomic dysfunction and in this Brazilian cohort most cases were seronegative and do not have correlation with small-cell lung cancer in contrast with the current knowledge of disease.

2002 ◽  
Vol 72 (1-2) ◽  
pp. 93-99 ◽  
Srinivas Gullapalli ◽  
Kumar V.S. Nemmani ◽  
Poduri Ramarao

1988 ◽  
Vol 255 (4) ◽  
pp. E469-E474
J. P. Kile ◽  
M. S. Amoss

It has been proposed that gonadotropin-releasing hormone (GnRH) stimulates Ca2+ entry by activation of voltage-independent, receptor-mediated Ca2+ channels in the rat gonadotroph. Little work has been done on the role of calcium in GnRH-induced luteinizing hormone (LH) release in species other than the rat. Therefore, this study was done to compare the effects of agents that alter Ca2+ or Na+ entry on LH release from calf anterior pituitary primary cells in culture. GnRH (100 ng/ml), Ca2+ ionophore A23187 (2.5 microM), and the depolarizing agent ouabain (0.1-10 microM) all produced significant increases (P less than 0.05) in LH release; these effects were significantly reduced when the cells were preincubated with the organic Ca2+ channel blockers nifedipine (1-10 microM) and verapamil (1-10 microM) and with Co2+ (0.01-1 mM). The effect of ouabain was inhibited by tetrodotoxin (TTX; 1-10 nM) as well as by nifedipine at 0.1-10 microM. In contrast to its effect on rat pituitary LH release, TTX significantly inhibited GnRH-stimulated LH release at 1-100 nM. These results suggest that GnRH-induced LH release may employ Ca2+ as a second messenger in bovine gonadotrophs and support recent speculation that GnRH-induced Ca2+ mobilization may in part be voltage dependent.

2021 ◽  
pp. 1-3
Setareh Alabaf ◽  
Karen O'Connell ◽  
Sithara Ramdas ◽  
David Beeson ◽  
Jacqueline Palace

Congenital Myasthenic Syndrome (CMS) are a rare group of genetic disorders of neuromuscular transmission. Some subtypes of CMS can be associated with respiratory and bulbar weakness and these patients may therefore be at high risk of developing a severe disease from COVID-19. We screened 73 patients with genetically confirmed CMS who were attending the UK national referral centre for evidence of previous Severe Acute Respiratory Syndrome Corona Virus 2 infection and their clinical outcome. Of 73 patients, seven had history of confirmed COVID-19. None of the infected patients developed a severe disease, and there were no signals that CMS alone carries a high risk of severe disease from COVID-19.

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