Synaptic congenital myasthenic syndromes

General Information (adopted from Orphanet):

Synonyms, Signs: MYASTHENIC SYNDROME, CONGENITAL, ENGEL TYPE
ENGEL CONGENITAL MYASTHENIC SYNDROME
CMS1C
EAD
CMS Ic
CONGENITAL MYASTHENIC SYNDROME TYPE Ic
Number of Symptoms 42
OrphanetNr: 98915
OMIM Id: 603034
ICD-10: G70.2
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal recessive inheritance
[Omim]
Age of onset: Infantile onset
[Omim]

Disease classification (adopted from Orphanet):

Parent Diseases: Congenital myasthenic syndromes
 -Rare eye disease
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
 (HPO:0000597) Ophthalmoparesis 71 / 7739
2
 (HPO:0000508) Ptosis 459 / 7739
3
 (HPO:0001260) Dysarthria 329 / 7739
4
 (HPO:0003388) Easy fatigability 34 / 7739
5
 (HPO:0003473) Fatigable weakness 39 / 7739
6
 (HPO:0003436) Prolonged miniature endplate currents 2 / 7739
7
 (HPO:0003443) Decreased size of nerve terminals 3 / 7739
8
 (HPO:0002015) Dysphagia 301 / 7739
9
 (HPO:0003307) Hyperlordosis 122 / 7739
10
 (HPO:0002650) Scoliosis 705 / 7739
11
 (HPO:0008872) Feeding difficulties in infancy 153 / 7739
12
 (HPO:0002093) Respiratory insufficiency 410 / 7739
13
 (HPO:0002747) Respiratory insufficiency due to muscle weakness 48 / 7739
14
 (HPO:0001612) Weak cry 17 / 7739
15
 (HPO:0002715) Abnormality of the immune system 46 / 7739
16
 (HPO:0008947) Infantile muscular hypotonia 482 / 7739
17
 (HPO:0001252) Muscular hypotonia 990 / 7739
18
 (HPO:0001324) Muscle weakness 859 / 7739
19
 (HPO:0010547) Muscle flaccidity 466 / 7739
20
 (HPO:0003324) Generalized muscle weakness 48 / 7739
21
 (HPO:0003403) EMG: decremental response of compound muscle action potential to repetitive nerve stimulation 7 / 7739
22
 (HPO:0003690) Limb muscle weakness 41 / 7739
23
 (HPO:0003199) Decreased muscle mass 27 / 7739
24
 (HPO:0003554) Type 2 muscle fiber atrophy 14 / 7739
25
 (OMIM) Decreased frequency of MEPP 1 / 7739
26
 (OMIM) Muscle biopsy shows abnormal encasement of presynaptic membrane by Schwann cells 1 / 7739
27
 (OMIM) Muscle biopsy shows decreased size of nerve terminals 1 / 7739
28
 (OMIM) Muscle biopsy shows endplate myopathy (see details under NEUROLOGIC heading) 1 / 7739
29
 (OMIM) Absence of acetylcholine receptor (AChR) autoantibodies 8 / 7739
30
 (OMIM) Multiple CMAP response to single nerve stimulation 1 / 7739
31
 (OMIM) Slow, delayed pupillary light reflex 1 / 7739
32
 (OMIM) Muscle biopsy shows type 2 fiber atrophy 6 / 7739
33
 (OMIM) Poor feeding due to muscle weakness 5 / 7739
34
 (OMIM) Muscle biopsy shows focal degeneration of postsynaptic junctional folds 1 / 7739
35
 (OMIM) Muscle biopsy shows absence of acetylcholinesterase (AChE) from neuromuscular junction 1 / 7739
36
 (HPO:0003593) Infantile onset 249 / 7739
37
 (OMIM) Muscle biopsy shows decreased postsynaptic membrane density 1 / 7739
38
 (OMIM) Muscle biopsy shows decreased size of endplates 1 / 7739
39
 (OMIM) Generalized weakness due to defect at the neuromuscular junction 1 / 7739
40
 (HPO:0000007) Autosomal recessive inheritance 2538 / 7739
41
 (OMIM) EMG shows decremental compound muscle action potential (CMAP) response to repetitive nerve stimulation 2 / 7739
42
 (OMIM) Weakness is exacerbated by exertion 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Congenital myasthenic syndromes (CMS) are genetic disorders of the neuromuscular junction that can be classified by the site of the transmission defect: presynaptic, synaptic, and postsynaptic. Endplate AChE deficiency is an autosomal recessive congenital myasthenic syndrome characterized by ...
Clinical Description OMIM Engel et al. (1977) reported a patient with a severely disabling CMS associated with endplate acetylcholinesterase deficiency. Symptoms began soon after birth with generalized weakness increased by exertion, fatigability, hyporeflexia, and no response to AChE inhibitors. EMG showed ...
Molecular genetics OMIM In 6 patients with AChE deficiency, Ohno et al. (1998) identified 6 recessive mutations in the COLQ gene (603033.0001-603033.0006). Two of the patients had previously been reported by Engel et al. (1977) and Hutchinson et al. (1993). ...