Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033377 (prolapse)
 11,717 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Systemic injection of monoclonal antibodies to neural acetylcholinesterase in adult rats caused a syndrome with permanent, complement-mediated destruction of presynaptic fibers in sympathetic ganglia and adrenal medulla. Ptosis, hypotension, bradycardia, and postural syncope ensued. In sympathetic ganglia, acetylcholinesterase activity disappeared from neuropil but not from nerve cell bodies. Choline acetyltransferase activity and ultrastructurally defined synapses were also lost. Electrical stimulation of presynaptic fibers to the superior cervical ganglion ceased to evoke end-organ responses. On the other hand, direct ganglionic stimulation remained effective, and the postganglionic adrenergic system appeared intact. Motor performance and the choline acetyltransferase content of skeletal muscle were preserved, as was parasympathetic (vagal) function. This model of selective cholinergic autoimmunity represents another tool for autonomic physiology and may be relevant to the pathogenesis of human dysautonomias.
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PMID:Autoimmune preganglionic sympathectomy induced by acetylcholinesterase antibodies. 217 9

After injury of their axons, damaged neurons shift their metabolic activity into a reparative mode aimed at survival and regeneration or, alternatively, they undergo degeneration and die. Previous reports have shown that at the initial stages of the response to axonal injury, polyamines are essential for neuronal survival and can accelerate functional recovery. In this study we examined the ability of exogenous polyamines to accelerate regeneration following crush of the pre- or postganglionic sympathetic nerves of the superior cervical ganglion in adult rats. We found that early treatment with polyamines after pre- or postganglionic nerve crush, accelerated the reappearance of choline acetyltransferase activity in the superior cervical ganglion, and of [3H]norepinephrine uptake in the iris, respectively. Functional recovery from eyelid ptosis was also accelerated. We conclude that treatment with polyamines can enhance regeneration of peripheral sympathetic neurons.
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PMID:Early polyamine treatment accelerates regeneration of rat sympathetic neurons. 370 40

Systemically injected anti-acetylcholinesterase antibodies in rats cause selective lesions of preganglionic sympathetic neurons. Adult rats were examined up to four months after a single i.v. injection of murine monoclonal acetylcholinesterase antibodies or normal immunoglobulin G (1.5 mg). Within 4 h, antibody-treated rats developed ptosis, a sign of sympathetic dysfunction that was never reversed. Persistent pupillary constriction reflected preserved and unopposed parasympathetic function. Weight gain was depressed, but locomotor activity, excitability, and sensorimotor responses were normal, and gross neuromuscular performance was near normal. These findings were supported by biochemical evidence for selective sympathetic damage. Acetylcholinesterase activity was reduced for the whole period of observation in sympathetic ganglia and adrenal glands but fell only transiently in muscle and serum. At all times, choline acetyltransferase activity (a marker of presynaptic terminals) was unaffected in muscle but grossly depleted in ganglia. Light and electron microscopy showed that preganglionic sympathetic terminals of superior cervical ganglia were severely damaged while parasympathetic ganglia were less affected and motor endplates of skeletal muscle were apparently spared. Immunocytochemistry revealed punctate deposits of murine immunoglobulin G and complement component C3 in ganglionic neuropil 12 h after antibody injection. This finding was consistent with complement-mediated lysis of preganglionic terminals. Morphometric analysis of preganglionic neurons in the intermediolateral nucleus of the spinal cord showed progressive loss of cholinergic perikarya over several months. We conclude that antibody-induced destruction of ganglionic terminals leads to death of preganglionic sympathetic neurons and, hence, permanent dysautonomia.
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PMID:Death of intermediolateral spinal cord neurons follows selective, complement-mediated destruction of peripheral preganglionic sympathetic terminals by acetylcholinesterase antibodies. 851 42

The sudden infant death syndrome has multiple etiologies. Some congenital myasthenic syndromes can cause sudden infant death syndrome by apnea, but the frequency of this etiology is unknown. We report here a young patient with sudden respiratory crises culminating in apnea followed by recovery, against a background of no or variable myasthenic symptoms without dyspnea. One sib without myasthenic symptoms and one sib who only had mild ptosis died previously during febrile episodes. Studies reported by us elsewhere traced the proband's illness to mutations in choline acetyltransferase. Here, we describe in detail the morphologic investigations and electrophysiologic findings, which point to a presynaptic defect in acetylcholine resynthesis or vesicular filling, in the proband. Analysis of DNA from a sib who previously died of sudden infant death syndrome revealed the same choline acetyltransferase mutation. Thus, mutations in choline acetyltransferase may be a cause of sudden infant death syndrome as, theoretically, could other presynaptic myasthenic disorders.
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PMID:Congenital myasthenic syndrome associated with episodic apnea and sudden infant death. 1211 78

Congenital myasthenic syndromes are caused by different genetic defects affecting proteins expressed at the neuromuscular junction. Recently, the first molecular genetic defect resulting in a presynaptic congenital myasthenic syndrome has been reported: Recessive loss-of-function mutations in CHAT, the gene encoding choline acetyltransferase, were described in five congenital myasthenic syndrome families. In this study, we investigated three patients from two independent Turkish kinships. Clinically, all patients presented with moderate myasthenic symptoms including ptosis and muscle weakness with increased fatigability. Multiple episodes of sudden apnea were reported for all patients. One child suffering from a second, unrelated disorder, i.e. hepatocellular carcinoma, showed a severe myasthenic phenotype, requiring permanent ventilation. Genetically, we identified a novel missense mutation (I336T) in the CHAT gene homozygously in all three patients. Haplotype analysis revealed that the mutant allele cosegregates with the clinical phenotype in both families (maximum combined two-point LOD-score of 2.46 for D10S1793). In summary, we confirm that CHAT mutations are responsible for a clinically distinct form of congenital myasthenic syndrome, characterized by episodic apnea. Infections and stress may lead to a life-threatening failure of neuromuscular transmission in congenital myasthenic syndrome with episodic apnea. The observation of the same mutation (I336T) in two independent Turkish kinships may suggest a common origin, i.e. founder.
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PMID:Congenital myasthenic syndrome due to a novel missense mutation in the gene encoding choline acetyltransferase. 1260 6

We report a severe case of congenital myasthenia gravis in a Chinese newborn who presented with complete ptosis, severe hypotonia, dysphagia and respiratory insufficiency with recurrent apnea that required mechanical ventilatory support since birth. Routine neurophysiologic studies, including the 3-Hz repetitive stimulation test and electromyogram were normal. Neostigmine and edrophonium tests were also negative. However, decremental response to 3-Hz stimulation became apparent after depleting the muscles with trains of 10-Hz stimuli for 10 min. The infant was subsequently confirmed to have heterozygous mutations in the choline acetyltransferase genes, p.T553N and p.S704P. Both missense mutations are novel mutations. The child remained on positive pressure ventilation at 3 years of age despite treatment with high-dose anticholinesterase. This case highlights the difficulty of making an early diagnosis based on clinical presentation and routine electrophysiologic tests, especially when neonatologists are not familiar with this condition. Further, as there are different genetic defects causing different types of congenital myasthenia gravis, anticholinesterase therapy may be beneficial to some but detrimental to others. Therefore, the exact molecular diagnosis is an important guide to therapy. A high index of suspicion coupled with extended electrodiagnostic tests in clinically suspected patients will ensure the selection of appropriate genetic molecular study for confirming the diagnosis.
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PMID:Severe congenital myasthenia gravis of the presynaptic type with choline acetyltransferase mutation in a Chinese infant with respiratory failure. 1879 71

Congenital myasthenic syndromes are a genetically and phenotypically heterogeneous group of hereditary disorders affecting neuromuscular junction. Mutations in the gene encoding choline acetyltransferase cause presynaptic defects. The missense mutation I336T has been identified in Turkish population, and most of the cases carrying this mutation present with exercise-induced fatigability and ptosis. Although apneic attacks occur in these cases during febrile illness in childhood, the number of reported respiratory distress episodes during infancy is scarce. Another important feature of these cases is that response to esterase inhibitors is satisfactory. We present a case of congenital myasthenic syndrome with I336T choline acetyltransferase mutation who presented with numerous attacks of respiratory distress in the infancy period. Interestingly, the patient had myopathic findings on electromyography and diazepam decreased severity of apneic attacks. There was also no improvement with esterase inhibitors.
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PMID:Temporary diazepam responsive apneic attacks and congenital myasthenic syndrome. 1928 95

Congenital myasthenic syndrome is difficult to diagnose, especially in the neonate when classic myasthenic signs may not be present. Congenital myasthenic syndrome with episodic apnea is a rare cause of recurrent apnea in infancy. We present an infant with nine severe episodes of apnea in her first 6 months who underwent a prolonged evaluation before ptosis was evident, leading to a diagnosis of choline acetyltransferase deficiency, a form of congenital myasthenic syndrome. Midazolam appeared to resolve the apnea on five occasions. The diagnosis was supported by edrophonium testing and repetitive nerve stimulation. Mutation analysis demonstrated compound heterozygous p.T354M and p.A557T mutations, the latter of which is novel. The patient's respiratory status stabilized on pyridostigmine, and she is ambulatory at age 3 years. Pyridostigmine is the primary therapy for choline acetyltransferase deficiency, but the efficacy of midazolam during this patient's episodes of apnea is interesting, and warrants further study.
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PMID:Congenital myasthenic syndrome with episodic apnea. 1952 Feb 74

We report 24 unrelated individuals with deletions and 17 additional cases with duplications at 10q11.21q21.1 identified by chromosomal microarray analysis. The rearrangements range in size from 0.3 to 12 Mb. Nineteen of the deletions and eight duplications are flanked by large, directly oriented segmental duplications of >98% sequence identity, suggesting that nonallelic homologous recombination (NAHR) caused these genomic rearrangements. Nine individuals with deletions and five with duplications have additional copy number changes. Detailed clinical evaluation of 20 patients with deletions revealed variable clinical features, with developmental delay (DD) and/or intellectual disability (ID) as the only features common to a majority of individuals. We suggest that some of the other features present in more than one patient with deletion, including hypotonia, sleep apnea, chronic constipation, gastroesophageal and vesicoureteral refluxes, epilepsy, ataxia, dysphagia, nystagmus, and ptosis may result from deletion of the CHAT gene, encoding choline acetyltransferase, and the SLC18A3 gene, mapping in the first intron of CHAT and encoding vesicular acetylcholine transporter. The phenotypic diversity and presence of the deletion in apparently normal carrier parents suggest that subjects carrying 10q11.21q11.23 deletions may exhibit variable phenotypic expressivity and incomplete penetrance influenced by additional genetic and nongenetic modifiers.
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PMID:Recurrent deletions and reciprocal duplications of 10q11.21q11.23 including CHAT and SLC18A3 are likely mediated by complex low-copy repeats. 2194 86

Congenital myasthenic syndromes (CMSs) are a group of inherited disorders caused by genetic defects in neuromuscular junctions. Mutations in CHAT, encoding choline acetyltransferase, cause congenital myasthenic syndrome with episodic apnea (CMS-EA), a rare autosomal recessive disease characterized by respiratory insufficiency with cyanosis and apnea after infections, fever, vomiting, or excitement. To date, no studies have reported deletions comprised of multiple exons. Here, using next generation sequencing, we identified compound heterozygous mutations, namely a large maternally inherited deletion, including exons 4, 5, and 6, and a paternally inherited missense variant (c.914T>C [p.Ile305Thr]) in CHAT in a Chinese patient with a severe phenotype of CMS-EA. Furthermore, the large deletion was also validated by real-time fluorescence quantitative polymerase chain reaction. The patient was a 10-month-old boy, who presented with a weak cry and feeding difficulties soon after birth, ptosis at 4 months old, episodic apnea after fever at 9 months old, and respiratory insufficiency with cyanosis and apnea that required intubation after a respiratory tract infection at 10 months old. Unfortunately, he died in the Pediatric Intensive Care Unit soon after hospitalization. The patient's elder sister had similar clinical manifestations, and she died prior to the age of 2 months old without a diagnosis. Genotype-phenotype correlation analysis revealed that loss-of-function mutations in exons 4-6 of CHAT might cause more severe CMS-EA. To our knowledge, this is the first study to show compound heterozygous CHAT mutations consisting of a large deletion and missense mutation in a patient with CMS-EA.
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PMID:Compound Heterozygous CHAT Gene Mutations of a Large Deletion and a Missense Variant in a Chinese Patient With Severe Congenital Myasthenic Syndrome With Episodic Apnea. 3091 58


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