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Congenital myasthenic syndrome 5(EAD; CMS1C, FORMERLY; CMS5)

MedGen UID:
400481
Concept ID:
C1864233
Disease or Syndrome
Synonyms: COLQ-Related Congenital Myasthenic Syndrome; Endplate acetylcholinesterase deficiency
 
Gene (location): COLQ (3p25.1)
 
Monarch Initiative: MONDO:0011281
OMIM®: 603034

Definition

Congenital myasthenic syndromes (CMS) are a group of inherited disorders affecting the neuromuscular junction. Patients present clinically with onset of variable muscle weakness between infancy and adulthood. These disorders have been classified according to the location of the defect: presynaptic, synaptic, and postsynaptic. Endplate acetylcholinesterase deficiency is an autosomal recessive congenital myasthenic syndrome characterized by a defect within the synapse at the neuromuscular junction (NMJ). Mutations in COLQ result in a deficiency of acetylcholinesterase (AChE), which causes prolonged synaptic currents and action potentials due to extended residence of acetylcholine in the synaptic space. Treatment with ephedrine may be beneficial; AChE inhibitors and amifampridine should be avoided (summary by Engel et al., 2015). For a discussion of genetic heterogeneity of CMS, see CMS1A (601462). [from OMIM]

Additional description

From MedlinePlus Genetics
Some individuals have episodes of breathing problems that may be triggered by fevers or infection. Severely affected individuals may also experience short pauses in breathing (apnea) that can lead to a bluish appearance of the skin or lips (cyanosis).

Congenital myasthenic syndrome is a group of conditions characterized by muscle weakness (myasthenia) that worsens with physical exertion. The muscle weakness typically begins in early childhood but can also appear in adolescence or adulthood. Facial muscles, including muscles that control the eyelids, muscles that move the eyes, and muscles used for chewing and swallowing, are most commonly affected. However, any of the muscles used for movement (skeletal muscles) can be affected in this condition. Due to muscle weakness, affected infants may have feeding difficulties. Development of motor skills such as crawling or walking may be delayed. The severity of the myasthenia varies greatly, with some people experiencing minor weakness and others having such severe weakness that they are unable to walk.  https://medlineplus.gov/genetics/condition/congenital-myasthenic-syndrome

Clinical features

From HPO
Limb muscle weakness
MedGen UID:
107956
Concept ID:
C0587246
Finding
Reduced strength and weakness of the muscles of the arms and legs.
Dysphagia
MedGen UID:
41440
Concept ID:
C0011168
Disease or Syndrome
Difficulty in swallowing.
Feeding difficulties in infancy
MedGen UID:
436211
Concept ID:
C2674608
Finding
Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention.
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.
Fatigable weakness
MedGen UID:
451076
Concept ID:
C0947912
Disease or Syndrome
A type of weakness that occurs after a muscle group is used and lessens if the muscle group has some rest. That is, there is diminution of strength with repetitive muscle actions.
Easy fatigability
MedGen UID:
373253
Concept ID:
C1837098
Finding
Increased susceptibility to fatigue.
Prolonged miniature endplate currents
MedGen UID:
350370
Concept ID:
C1864238
Finding
An abnormal prolongation of the miniature endplate potentials, i.e. the postsynaptic response to transmitter released from an individual vesicle at the neuromuscular junction.
Decreased size of nerve terminals
MedGen UID:
871144
Concept ID:
C4025615
Anatomical Abnormality
A reduction in the size of nerve terminals.
Hyperlordosis
MedGen UID:
9805
Concept ID:
C0024003
Finding
Abnormally increased curvature (anterior concavity) of the lumbar or cervical spine.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Myopathy
MedGen UID:
10135
Concept ID:
C0026848
Disease or Syndrome
A disorder of muscle unrelated to impairment of innervation or neuromuscular junction.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Decreased strength of the neck musculature.
Generalized muscle weakness
MedGen UID:
155433
Concept ID:
C0746674
Sign or Symptom
Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature.
Decreased muscle mass
MedGen UID:
373256
Concept ID:
C1837108
Finding
Type 1 muscle fiber predominance
MedGen UID:
344274
Concept ID:
C1854387
Finding
An abnormal predominance of type I muscle fibers (in general, this feature can only be observed on muscle biopsy).
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Type 2 muscle fiber atrophy
MedGen UID:
355249
Concept ID:
C1864580
Pathologic Function
Atrophy (wasting) affecting primary type 2 muscle fibers. This feature in general can only be observed on muscle biopsy.
EMG: decremental response of compound muscle action potential to repetitive nerve stimulation
MedGen UID:
892749
Concept ID:
C4021728
Finding
A compound muscle action potential (CMAP) is a type of electromyography (EMG). CMAP refers to a group of almost simultaneous action potentials from several muscle fibers in the same area evoked by stimulation of the supplying motor nerve and are recorded as one multipeaked summated action potential. This abnormality refers to a greater than normal decrease in the amplitude during the course of the investigation.
Respiratory insufficiency
MedGen UID:
11197
Concept ID:
C0035229
Pathologic Function
Impairment of gas exchange within the lungs secondary to a disease process, neoplasm, or trauma, possibly resulting in hypoxia, hypercarbia, or both, but not requiring intubation or mechanical ventilation. Patients are normally managed with pharmaceutical therapy, supplemental oxygen, or both.
Respiratory insufficiency due to muscle weakness
MedGen UID:
812797
Concept ID:
C3806467
Finding
Anti-acetylcholine receptor antibody positivity
MedGen UID:
868186
Concept ID:
C4022578
Finding
The presence of autoantibodies (immunoglobulins) in the blood circulation that react against ganglioside-monosialic acid (GM1), which is a type of glycosphingolipid with one sialic acid. GM1 is located on the outer layer of the plasma membrane, and plays a vital role in neurogenesis, nerve development, differentiation and repair after injury.
Weak cry
MedGen UID:
65892
Concept ID:
C0234860
Finding
Ptosis
MedGen UID:
2287
Concept ID:
C0005745
Disease or Syndrome
The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).
Ophthalmoparesis
MedGen UID:
155551
Concept ID:
C0751401
Sign or Symptom
Ophthalmoplegia is a paralysis or weakness of one or more of the muscles that control eye movement.

Professional guidelines

PubMed

Özsoy Ö, Cinleti T, Günay Ç, Sarıkaya Uzan G, Giray Bozkaya Ö, Çağlayan AO, Hız Kurul S, Yiş U
Acta Neurol Belg 2023 Dec;123(6):2325-2335. Epub 2023 Sep 1 doi: 10.1007/s13760-023-02370-3. PMID: 37656362
Vanhaesebrouck AE, Beeson D
Curr Opin Neurol 2019 Oct;32(5):696-703. doi: 10.1097/WCO.0000000000000736. PMID: 31361628Free PMC Article
Tsao CY
Pediatr Neurol 2016 Jan;54:85-7. Epub 2015 Nov 6 doi: 10.1016/j.pediatrneurol.2015.09.019. PMID: 26552645

Recent clinical studies

Etiology

Ohno K, Ohkawara B, Shen XM, Selcen D, Engel AG
Int J Mol Sci 2023 Feb 13;24(4) doi: 10.3390/ijms24043730. PMID: 36835142Free PMC Article
Estephan EP, Zambon AA, Thompson R, Polavarapu K, Jomaa D, Töpf A, Helito PVP, Heise CO, Moreno CAM, Silva AMS, Kouyoumdjian JA, Morita MDP, Reed UC, Lochmüller H, Zanoteli E
Eur J Neurol 2022 Mar;29(3):833-842. Epub 2021 Nov 17 doi: 10.1111/ene.15173. PMID: 34749429
Megarbane A, Bizzari S, Deepthi A, Sabbagh S, Mansour H, Chouery E, Hmaimess G, Jabbour R, Mehawej C, Alame S, Hani A, Hasbini D, Ghanem I, Koussa S, Al-Ali MT, Obeid M, Talea DB, Lefranc G, Lévy N, Leturcq F, El Hayek S, Delague V, Urtizberea JA
J Neuromuscul Dis 2022;9(1):193-210. doi: 10.3233/JND-210652. PMID: 34602496Free PMC Article
Zhao Y, Li Y, Bian Y, Yao S, Liu P, Yu M, Zhang W, Wang Z, Yuan Y
Ann Clin Transl Neurol 2021 Apr;8(4):898-907. Epub 2021 Mar 23 doi: 10.1002/acn3.51346. PMID: 33756069Free PMC Article
Finsterer J
Orphanet J Rare Dis 2019 Feb 26;14(1):57. doi: 10.1186/s13023-019-1025-5. PMID: 30808424Free PMC Article

Diagnosis

Ohno K, Ohkawara B, Shen XM, Selcen D, Engel AG
Int J Mol Sci 2023 Feb 13;24(4) doi: 10.3390/ijms24043730. PMID: 36835142Free PMC Article
Estephan EP, Zambon AA, Thompson R, Polavarapu K, Jomaa D, Töpf A, Helito PVP, Heise CO, Moreno CAM, Silva AMS, Kouyoumdjian JA, Morita MDP, Reed UC, Lochmüller H, Zanoteli E
Eur J Neurol 2022 Mar;29(3):833-842. Epub 2021 Nov 17 doi: 10.1111/ene.15173. PMID: 34749429
Megarbane A, Bizzari S, Deepthi A, Sabbagh S, Mansour H, Chouery E, Hmaimess G, Jabbour R, Mehawej C, Alame S, Hani A, Hasbini D, Ghanem I, Koussa S, Al-Ali MT, Obeid M, Talea DB, Lefranc G, Lévy N, Leturcq F, El Hayek S, Delague V, Urtizberea JA
J Neuromuscul Dis 2022;9(1):193-210. doi: 10.3233/JND-210652. PMID: 34602496Free PMC Article
Gonzalez-Quereda L, Rodriguez MJ, Diaz-Manera J, Alonso-Perez J, Gallardo E, Nascimento A, Ortez C, Natera-de Benito D, Olive M, Gonzalez-Mera L, Munain AL, Zulaica M, Poza JJ, Jerico I, Torne L, Riera P, Milisenda J, Sanchez A, Garrabou G, Llano I, Madruga-Garrido M, Gallano P
Genes (Basel) 2020 May 11;11(5) doi: 10.3390/genes11050539. PMID: 32403337Free PMC Article
Finsterer J
Orphanet J Rare Dis 2019 Feb 26;14(1):57. doi: 10.1186/s13023-019-1025-5. PMID: 30808424Free PMC Article

Therapy

Eshaghian T, Rabbani B, Badv RS, Mikaeeli S, Gharib B, Iyadurai S, Mahdieh N
Neurogenetics 2023 Jul;24(3):189-200. Epub 2023 May 25 doi: 10.1007/s10048-023-00719-7. PMID: 37231228
Shao S, Shi G, Bi FF, Huang K
Curr Neuropharmacol 2023;21(7):1594-1605. doi: 10.2174/1570159X21666230126145652. PMID: 36703579Free PMC Article
Finsterer J
Orphanet J Rare Dis 2019 Feb 26;14(1):57. doi: 10.1186/s13023-019-1025-5. PMID: 30808424Free PMC Article
Tsao CY
Pediatr Neurol 2016 Jan;54:85-7. Epub 2015 Nov 6 doi: 10.1016/j.pediatrneurol.2015.09.019. PMID: 26552645
Gilhus NE
Curr Opin Neurol 2012 Oct;25(5):523-9. doi: 10.1097/WCO.0b013e3283572588. PMID: 22892950

Prognosis

Vianello A, Racca F, Vita GL, Pierucci P, Vita G
Handb Clin Neurol 2022;189:259-270. doi: 10.1016/B978-0-323-91532-8.00014-8. PMID: 36031308
Zhao Y, Li Y, Bian Y, Yao S, Liu P, Yu M, Zhang W, Wang Z, Yuan Y
Ann Clin Transl Neurol 2021 Apr;8(4):898-907. Epub 2021 Mar 23 doi: 10.1002/acn3.51346. PMID: 33756069Free PMC Article
Juel VC, Massey JM
Orphanet J Rare Dis 2007 Nov 6;2:44. doi: 10.1186/1750-1172-2-44. PMID: 17986328Free PMC Article
Hantaï D, Richard P, Koenig J, Eymard B
Curr Opin Neurol 2004 Oct;17(5):539-51. doi: 10.1097/00019052-200410000-00004. PMID: 15367858
Beeson D, Palace J, Vincent A
Curr Opin Neurol 1997 Oct;10(5):402-7. doi: 10.1097/00019052-199710000-00008. PMID: 9330886

Clinical prediction guides

Zhao Y, Li Y, Bian Y, Yao S, Liu P, Yu M, Zhang W, Wang Z, Yuan Y
Ann Clin Transl Neurol 2021 Apr;8(4):898-907. Epub 2021 Mar 23 doi: 10.1002/acn3.51346. PMID: 33756069Free PMC Article
Troha Gergeli A, Neubauer D, Golli T, Butenko T, Loboda T, Maver A, Osredkar D
Eur J Paediatr Neurol 2020 May;26:34-38. Epub 2020 Feb 11 doi: 10.1016/j.ejpn.2020.02.002. PMID: 32070632
Engel AG, Shen XM, Selcen D
Ann N Y Acad Sci 2018 Feb;1413(1):25-34. Epub 2018 Jan 21 doi: 10.1111/nyas.13539. PMID: 29355968Free PMC Article
McMacken G, Whittaker RG, Evangelista T, Abicht A, Dusl M, Lochmüller H
J Neurol 2018 Jan;265(1):194-203. Epub 2017 Nov 30 doi: 10.1007/s00415-017-8689-3. PMID: 29189923Free PMC Article
Engel AG, Sine SM
Curr Opin Pharmacol 2005 Jun;5(3):308-21. doi: 10.1016/j.coph.2004.12.007. PMID: 15907919

Recent systematic reviews

Finsterer J
Orphanet J Rare Dis 2019 Feb 26;14(1):57. doi: 10.1186/s13023-019-1025-5. PMID: 30808424Free PMC Article

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