scholarly journals A novel mutation of the COLQ gene causes congenital myasthenic syndromes: A case report

2021 ◽  
Vol 26 (4) ◽  
pp. 845-847
Author(s):  
Shiyi Yang ◽  
Jing Luo ◽  
Fei Xiao
Keyword(s):  
Case Report ◽  
Neuromuscular Junctions ◽  
Clinical Symptoms ◽  
Novel Mutation ◽  
Compound Muscle Action Potential ◽  
Nerve Conduction Studies ◽  
Muscle Action ◽  
Congenital Myasthenic Syndromes ◽  
Muscle Action Potential ◽  
Myasthenic Syndromes

Congenital myasthenic syndromes (CMS) are a group of heterogeneous disorders of the neuromuscular junctions, characterised by fluctuating and fatigable weakness with an early onset. Endplate acetylcholinesterase deficiency (EAD) due to mutations in COLQ is a subtype of CMS whose key clue for diagnosis is repetitive compound muscle action potential (R-CMAP) under nerve conduction studies. In light of the significant overlap of clinical symptoms, misdiagnosis is common for CMS, causing delayed or incorrect treatments. Here, we report a case of CMS due to a novel mutation in COLQ with a typical R-CMAP and discuss the significance of R-CMAP for diagnosis.

Congenital Myasthenic Syndrome: Presentation, Electrodiagnosis, and Muscle Biopsy

2004 ◽  
Vol 19 (3) ◽  
pp. 175-182 ◽  
Author(s):  
Christina A. Gurnett ◽  
Judy A. Bodnar ◽  
Jeffrey Neil ◽  
Anne M. Connolly
Keyword(s):  
Action Potential ◽  
Nerve Stimulation ◽  
Compound Muscle Action Potential ◽  
Muscle Action ◽  
Repetitive Nerve Stimulation ◽  
Poor Growth ◽  
Congenital Myasthenic Syndromes ◽  
Feeding Difficulties ◽  
Muscle Action Potential ◽  
Myasthenic Syndromes

We report 10 children with congenital myasthenic syndromes diagnosed by clinical features, electrodiagnostic studies, and response to acetylcholinesterase inhibitors. Age at diagnosis (mean = 4.4 years; range 0.2–10 years) correlated with age fatigue was recognized. Symptoms at presentation included mild gross motor development delay (7/10), speech articulation difficulty (5/10), and respiratory and feeding difficulties resulting in poor growth in 7 of 10 children. None of the five children with possible presynaptic abnormalities had decremental compound muscle action potential responses to 2 Hz repetitive nerve stimulation. Instead, electrodiagnostic studies showed a more than 100% increment of compound muscle action potential amplitude during 50 Hz repetitive nerve stimulation in two children and sustained compound muscle action potential decrement to 2 Hz repetitive nerve stimulation after depletion (10 Hz stimulation for 10 min) in four children. Muscle biopsies ( n = 7) showed mild to severe variation in fiber size. Our experience suggests that many children with congenital myasthenic syndromes might be undiagnosed because of atypical presentation and because additional electrophysiologic studies are required.

Congenital Myasthenic Syndrome: Presentation, Electrodiagnosis, and Muscle Biopsy

2004 ◽  
Vol 19 (3) ◽  
pp. 175-182
Author(s):  
Christina A. Gurnett ◽  
Judy A. Bodnar ◽  
Jeffrey Neil ◽  
Anne M. Connolly
Keyword(s):  
Action Potential ◽  
Nerve Stimulation ◽  
Compound Muscle Action Potential ◽  
Muscle Action ◽  
Repetitive Nerve Stimulation ◽  
Poor Growth ◽  
Congenital Myasthenic Syndromes ◽  
Feeding Difficulties ◽  
Muscle Action Potential ◽  
Myasthenic Syndromes

We report 10 children with congenital myasthenic syndromes diagnosed by clinical features, electrodiagnostic studies, and response to acetylcholinesterase inhibitors. Age at diagnosis (mean = 4.4 years; range 0.2–10 years) correlated with age fatigue was recognized. Symptoms at presentation included mild gross motor development delay (7/10), speech articulation difficulty (5/10), and respiratory and feeding difficulties resulting in poor growth in 7 of 10 children. None of the five children with possible presynaptic abnormalities had decremental compound muscle action potential responses to 2 Hz repetitive nerve stimulation. Instead, electrodiagnostic studies showed a more than 100% increment of compound muscle action potential amplitude during 50 Hz repetitive nerve stimulation in two children and sustained compound muscle action potential decrement to 2 Hz repetitive nerve stimulation after depletion (10 Hz stimulation for 10 min) in four children. Muscle biopsies ( n = 7) showed mild to severe variation in fiber size. Our experience suggests that many children with congenital myasthenic syndromes might be undiagnosed because of atypical presentation and because additional electrophysiologic studies are required.

Late Responses

2016 ◽  
pp. 312-327
Author(s):  
Ruple S. Laughlin
Keyword(s):  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Motor Nerve ◽  
Clinical Applications ◽  
Nerve Conduction Studies ◽  
Sensory Nerves ◽  
Muscle Action ◽  
Physiological Basis ◽  
Motor Nerve Conduction ◽  
Muscle Action Potential

Late responses are a group of responses occurring after the compound muscle action potential (M-wave) in motor nerve conduction studies and include F-waves, H-reflexes, and axon reflexes. These responses can indirectly measure aspects of proximal conduction that are not obtained with routine motor nerve conduction studies and may be useful in assessing diseases that affect proximal nerves, such as polyradiculopathies. A thorough understanding of the physiological basis, sources of error, and clinical applications and limitations enhances the usefulness of F-waves and H-reflexes as one means to evaluate proximal functioning of the motor and sensory nerves. This chapter will discuss the study methods and applications of F-waves and H-reflexes.

scholarly journals Duration and temporal dispersion measurements in CIDP subjects from the Polyneuropathy And Treatment with Hizentra (PATH) study

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Deepak Menon ◽  
Joy Vijayan ◽  
John-Philip Lawo ◽  
Orell Mielke ◽  
Mylan Ngo ◽  
...  
Keyword(s):  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Nerve Conduction Studies ◽  
Muscle Action ◽  
Muscle Action Potential ◽  
End Of Treatment ◽  
Immunoglobulin Treatment ◽  
Consistent Method ◽  
The Impact ◽  
Temporal Dispersion

Abstract: Introduction: Distal compound muscle action potential (dCMAP) duration and temporal dispersion (TD) are electrophysiological hallmarks of demyelination and important for the diagnosis of CIDP. While the impact of CIDP treatment on other nerve conduction parameters has been examined, the effects on dCMAP and TD remain unexplored. The aim of the study was to examine the impact of withdrawal of immunoglobulin treatment on dCMAP duration and TD, and also the influence of the measurement technique on dCMAP duration and TD. Methods: Nerve conduction studies were analyzed from the PATH (Polyneuropathy And Treatment with Hizentra) study which randomized patients with CIDP to two doses of IgPro 20 and placebo. Distal CMAP duration and TD were obtained by two methods of measurements (D1 and D2, TD1 and TD2) from the median and peroneal nerves.   Results: The dCMAP and TD were obtained from 389 tracings. While the two methods of measurement showed differences in D1 and D2 with D2 longer than D1 in all the three groups, there was no difference between the TD1 and TD2. There was no difference at baseline in dCMAP duration or TD among the three groups. At the end of treatment, patients in the placebo arm had no worsening of dCMAP and TD compared to baseline or the treated groups. Conclusion: dCMAP duration and TD did not show a difference between treated and placebo groups, and may be less sensitive measures than other nerve conduction parameters when evaluating changes in treatment. The method of dCMAP duration measurement does not affect TD as long as a consistent method is followed.  

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