Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypokalemic periodic paralysis (HOKPP) is a rare disorder characterized by episodic muscle weakness with hypokalemia. Mutations in the CACNA1S gene, which encodes the alpha 1-subunit of the skeletal muscle L-type voltage-dependent calcium channel, have been reported to be mainly responsible for HOKPP. The paralytic attacks generally spare the respiratory muscles and the heart. Here, we report the case of a 16-year-old boy who presented with frequent respiratory insufficiency during the severe attacks. Mutational analysis revealed a heterozygous c.1582C>G substitution in the CACNA1S gene, leading to an Arg528Gly mutation in the protein sequence. The parents were clinically unaffected and did not show a mutation in the CACNA1S gene. A de novo Arg528Gly mutation has not previously been reported. The patient described here presents the unique clinical characteristics, including a severe respiratory phenotype and a reduced susceptibility to cold exposure. The patient did not respond to acetazolamide and showed a marked improvement of the paralytic symptoms on treatment with a combination of spironolactone, amiloride, and potassium supplements.
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PMID:Severe respiratory phenotype caused by a de novo Arg528Gly mutation in the CACNA1S gene in a patient with hypokalemic periodic paralysis. 1982 48

A 58-year-old man complaining of increasing weakness of muscular leg strength, diplopia and ptosis was admitted to our hospital. An electromyogram (EMG) showed typical waxing phenomenon in response to high-frequency repetitive stimulation. A diagnosis of Lambert-Eaton myasthenic syndrome (LEMS) was made from his symptoms and EMG results. A chest CT showed mediastinal lymph node swelling. No abnormal mass was seen in either lung field. His serum levels of a P/Q-type anti-voltage-gated calcium channel (VGCC) antibody, Pro-GRP, and NSE were high. FDG-PET showed accumulation of FDG to the mediastinal and left inguinal lymph nodes. The left inguinal lymphadenopathy was pathologically diagnosed as metastasis of small cell lung carcinoma. No tumor could be detected by bronchofiberscopy. No other distant metastasis was detected by brain MRI, abdominal CT, or FDG-PET. After 6 courses of chemotherapy for SCLC, a partial response and reduction of symptoms were obtained. For assessment of indistinguishable neuropathic symptoms, the possible diagnosis of paraneoplastic syndrome, such as LEMS, and the fact that early treatment for primary disease was effective, should be considered.
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PMID:[A case of small cell lung carcinoma without apparent primary lesion accompanying Lambert-Eaton myasthenic syndrome]. 2005 96

We report a 64-year-old man diagnosed with Lambert-Eaton myasthenic syndrome (LEMS) associated with pulmonary squamous cell carcinoma. Circulating anti-P/Q-type voltage-gated calcium channel (VGCC) antibody was detected, and the patient was treated with 3,4-diaminopyridine. At age 61, chest radiograph revealed a tumor shadow in the right upper lung field. This was surgically removed, and a histological diagnosis of moderately differentiated pulmonary squamous cell carcinoma was obtained. After about 1 year, mediastinal metastasis was detected and 5-FU was administered. Eight months later, metastasis was noted in the left frontal hemisphere, and radiosurgical therapy was performed. The brain tumor gradually shrank but generalized fatigue, thirst, and gait disturbance developed after 4 months. A diagnosis of LEMS was made on the basis of neurological findings including proximal muscle weakness and absent tendon reflexes; autonomic symptoms (thirst, constipation, and impotence); characteristic electromyographic findings; and circulating anti-P/Q-type VGCC antibody. He has been treated with 3,4-diaminopyridine at a dose of 30 mg/day, resulting in marked improvement in symptoms but little change in electromyographic findings. The present case is very rare and suggests that anti-P/Q-type VGCC antibody may be involved in the mechanism of LEMS associated with pulmonary squamous cell carcinoma.
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PMID:[Lambert-Eaton myasthenic syndrome associated with pulmonary squamous cell carcinoma and circulating anti-P/Q-type voltage-gated calcium channel antibody]. 2012 Mar 49

The neuromuscular junction is vulnerable to autoimmune attack both at the pre-synaptic nerve terminal and at the post-synaptic muscle membrane. Antibodies directed to the nicotinic acetylcholine receptor at the muscle surface are the cause of myasthenia gravis in the majority of cases. Myasthenia gravis is an acquired condition, characterised by weakness and fatigability of the skeletal muscles. The ocular muscles are commonly affected first, but the disease often generalises. Treatment includes symptom control and immunosuppression. The thymus gland plays an important role in the pathogenesis of myasthenia gravis and thymectomy is indicated in certain subgroups. Lambert-Eaton myasthenic syndrome is associated with antibodies directed to the voltage-gated calcium channel antibodies at the pre-synaptic nerve terminal. It is an acquired condition and, in some cases, may be paraneoplastic, often secondary to underlying small cell lung carcinoma. Clinical presentation is distinct from myasthenia gravis, with patients often first presenting with lower limb muscle fatigability and autonomic symptoms. Congenital myasthenic syndromes are inherited neuromuscular disorders due to mutations in proteins at the neuromuscular junction. Various phenotypes exist depending on the protein mutation. Treatment is directed towards symptom control and immunosuppression is not indicated.
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PMID:Myasthenic syndromes. 2136 67

We present the first case of small cell lung cancer with Lambert-Eaton myasthenic syndrome during hemodialysis (HD). A 72-year-old male patient receiving HD experienced progressive muscle weakness. He was diagnosed with small cell lung cancer with Lambert-Eaton myasthenic syndrome due to an increased serum level of anti-voltage-gated calcium channel antibody and aspiration cytology on endobronchial ultrasonography for the swelling of a subcarinal lymph node. He received chemotherapy consisting of carboplatin (300 mg/m(2)) and etoposide (50 mg/m(2)), to which he had a partial response. However, the second therapy course could not be administered because of the unexpected development of severe hematological adverse events, which also prevented him from undergoing further HD. This case indicates that caution should be taken when using chemotherapy for such patients because of hypotension due to chemotherapy, with which it is impossible to undergo HD.
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PMID:Hypotension due to Chemotherapy in a Patient with Small Cell Lung Cancer and Lambert-Eaton Myasthenic Syndrome Undergoing Hemodialysis: A First Case Report. 2242 46

A 62-year-old man who had suffered from instability of gait and double vision for two months was admitted to our hospital because of weakness of the extremities and ataxia of the extremities and trunk. Chest X-rays and CT scans showed enlargement of the left hilar lymph nodes and a nodular shadow in the left lung. Transbronchial biopsy revealed small cell lung cancer. We diagnosed the patient with two conditions: paraneoplastic cerebellar degeneration (PCD), based on cerebellar ataxia, the presence of Hu antineuronal antibodies, and the absence of cerebellar atrophy and malignancy; and Lambert-Eaton myasthenic syndrome (LEMS), based on weakness of the extremities, the presence of P/Q-type voltage-gated calcium channel antibodies, and waxing in the evoked electromyogram. Anticancer chemoradiation therapy that was started within three months of symptom onset resulted in reductions in size of the hilar lymph nodes and the nodule. Concurrently, cerebellar ataxia, weakness of the extremities, and double vision all disappeared. Anticancer chemotherapy is effective against LEMS while usually less effective against PCD. Early commencement of anticancer chemotherapy is recommended for the treatment of PCD with LEMS.
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PMID:[Synchronous appearance and improvement with anticancer chemotherapy of paraneoplastic cerebellar degeneration and Lambert-Eaton myasthenic syndrome complicated with small cell lung cancer]. 2347 Aug 89

Duchenne muscular dystrophy (DMD), induced by mutations in the gene encoding for the cytoskeletal protein dystrophin, is an inherited disease characterized by progressive muscle weakness. Besides the relatively well characterized skeletal muscle degenerative processes, DMD is also associated with cardiac complications. These include cardiomyopathy development and cardiac arrhythmias. The current understanding of the pathomechanisms in the heart is very limited, but recent research indicates that dysfunctional ion channels in dystrophic cardiomyocytes play a role. The aim of the present study was to characterize abnormalities in L-type calcium channel function in adult dystrophic ventricular cardiomyocytes. By using the whole cell patch-clamp technique, the properties of currents through calcium channels in ventricular cardiomyocytes isolated from the hearts of normal and dystrophic adult mice were compared. Besides the commonly used dystrophin-deficient mdx mouse model for human DMD, we also used mdx-utr mice, which are both dystrophin- and utrophin-deficient. We found that calcium channel currents were significantly increased, and channel inactivation was reduced in dystrophic cardiomyocytes. Both effects enhance the calcium influx during an action potential (AP). Whereas the AP in dystrophic mouse cardiomyocytes was nearly normal, implementation of the enhanced dystrophic calcium conductance in a computer model of a human ventricular cardiomyocyte considerably prolonged the AP. Finally, the described dystrophic calcium channel abnormalities entailed alterations in the electrocardiograms of dystrophic mice. We conclude that gain of function in cardiac L-type calcium channels may disturb the electrophysiology of the dystrophic heart and thereby cause arrhythmias.
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PMID:Enhanced currents through L-type calcium channels in cardiomyocytes disturb the electrophysiology of the dystrophic heart. 2433 61

We evaluated the efficacy of intravenous immunoglobulin (IVIg) in a patient with Lambert-Eaton myasthenic syndrome (LEMS). Comprehensive clinical and electrophysiological testing was performed on a 34-year-old woman with progressive limb weakness, before and after IVIg treatment. Neurological examination revealed muscle weakness, predominantly in the proximal parts of the limbs. Muscle weakness improved following a short period of maximum voluntary muscle contraction. A repetitive low-rate (3-Hz) nerve stimulation test of the abductor hallucis was normal, but high-rate (20-Hz) stimulation induced an incremental response. Anti-presynaptic P/Q-type voltage-gated calcium channel (P/Q-VGCC) antibodies were absent in the patient's serum. Whole body computed tomography revealed no tumors. We diagnosed seronegative LEMS without tumor and treated the patient with IVIg. Both clinical and electrophysiological indices improved gradually after treatment. This case study indicates that treatment with IVIg is equally effective for LEMS that is seronegative or seropositive for P/Q-VGCC antibodies.
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PMID:Efficacy of intravenous immunoglobulin for treatment of Lambert-Eaton myasthenic syndrome without anti-presynaptic P/Q-type voltage-gated calcium channel antibodies: a case report. 2544 32

We report a 50-year-old woman who presented with a 20 year history of gradually progressive lower extremity weakness, characterized by knee buckling with occasional falls and foot dragging. She also experienced difficulty in lifting her arms above her shoulders. The primary periodic paralyses are rare disorders caused by dysfunctional ion channels in skeletal muscle. The hypokalemic type is generally an autosomal dominant condition, due to missense mutations in the alpha subunits of the skeletal muscle L-type calcium channel genes, CACN1AS, or the skeletal muscle sodium channel gene, SCN4A. The affected patients typically present with episodic weakness. For our patient, the consumption of foods high in carbohydrates seemed to precipitate the episodes of weakness. Her family history was significant for six blood relatives, including three sons and three relatives on the paternal side, who had experienced similar symptoms. A biopsy of the left rectus femoralis muscle showed vacuolar myopathic changes in the scattered muscle fibers, accompanied by occasional degenerating and regenerating muscle fibers. There was no evidence of inflammation on the biopsy. The vacuoles were often associated with increased acid phosphatase staining. An electron microscopic examination showed that the vacuolar changes were due to T-tubule dilation, a characteristic of hypokalemic periodic paralysis. Other metabolic etiologies of vacuolar myopathy, such as acid phosphatase (lysosomal) associated acid maltase deficiency (a glycogen storage disease), need to be considered in the differential diagnosis.
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PMID:Episodic weakness and vacuolar myopathy in hypokalemic periodic paralysis. 2619 Feb 19

Lambert-Eaton myasthenic syndrome (LEMS) and botulism are acquired presynaptic nerve terminal disorders of the neuromuscular junction. Lambert-Eaton myasthenic syndrome is an idiopathic or paraneoplastic autoimmune syndrome in which autoantibodies of the P/Q-type voltage-gated calcium channel play a role in decreasing the release of acetylcholine, resulting in clinical symptoms of skeletal muscle weakness, diminished reflexes, and autonomic symptoms. Paraneoplastic LEMS is most often associated with small cell lung cancer. Diagnosis is confirmed by positive serologic testing and electrophysiological studies, which display characteristic features of low compound muscle action potentials, a decrement at 3Hz repetitive nerve stimulation, and facilitation with exercise or high-frequency repetitive stimulation. Treatment involves cancer monitoring and treatment, 3,4-diaminopyridine, immunosuppressive medications, and acetylcholinesterase inhibitors. Botulism is another presynaptic disorder of neuromuscular transmission. Clinical features classically involve cranial and bulbar palsies followed by descending weakness of the limbs, respiratory failure, and autonomic dysfunction. Electrodiagnostic testing is important in the evaluation and diagnosis. Treatment is supportive, and administration of antitoxin is beneficial in selected cases.
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PMID:Presynaptic Disorders: Lambert-Eaton Myasthenic Syndrome and Botulism. 2650 58


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