MYASTHENIC SYNDROME, CONGENITAL, 1A, SLOW-CHANNEL

General Information (adopted from Orphanet):

Synonyms, Signs: MYASTHENIC SYNDROME, CONGENITAL, POSTSYNAPTIC SLOW-CHANNEL
CMS2A
SCCMS
CMS IIa
MYASTHENIC SYNDROME, CONGENITAL, TYPE IIa
Number of Symptoms 32
OrphanetNr:
OMIM Id: 601462
ICD-10:
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

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

Disease classification (adopted from Orphanet):

Parent Diseases: No data available.

Symptom Information: Sort by abundance 

1
 (HPO:0000218) High palate rare [HPO:skoehler] 356 / 7739
2
 (HPO:0000508) Ptosis 459 / 7739
3
 (HPO:0000597) Ophthalmoparesis 71 / 7739
4
 (HPO:0000602) Ophthalmoplegia 56 / 7739
5
 (HPO:0002015) Dysphagia 301 / 7739
6
 (HPO:0003473) Fatigable weakness 39 / 7739
7
 (HPO:0003436) Prolonged miniature endplate currents 2 / 7739
8
 (HPO:0001260) Dysarthria 329 / 7739
9
 (HPO:0003443) Decreased size of nerve terminals 3 / 7739
10
 (HPO:0011968) Feeding difficulties 240 / 7739
11
 (HPO:0004889) Intermittent episodes of respiratory insufficiency due to muscle weakness 1 / 7739
12
 (HPO:0003554) Type 2 muscle fiber atrophy 14 / 7739
13
 (HPO:0003324) Generalized muscle weakness 48 / 7739
14
 (OMIM) Secondary loss of AChR from junctional folds seen on muscle biopsy 1 / 7739
15
 (OMIM) Extensor finger muscle weakness 1 / 7739
16
 (OMIM) EMG shows decremental CMAP response to repetitive nerve stimulation 1 / 7739
17
 (HPO:0000006) Autosomal dominant inheritance 2518 / 7739
18
 (OMIM) Type 2 fiber atrophy see on biopsy 1 / 7739
19
 (OMIM) Scapular muscle weakness 2 / 7739
20
 (OMIM) Decreased size of nerve terminals seen on muscle biopsy 1 / 7739
21
 (OMIM) Focal degeneration of junctional folds ('honeycombed' appearance) see on muscle biopsy 1 / 7739
22
 (OMIM) Calcium accumulation in junctional folds seen on muscle biopsy 1 / 7739
23
 (OMIM) Atrophy of affected muscles, especially intrinsic hand muscles 1 / 7739
24
 (OMIM) Chronic fatigable muscles 1 / 7739
25
 (OMIM) Increased opening duration of acetylcholine receptor (AChR)-induced ion channels 1 / 7739
26
 (OMIM) Progressive widening of synaptic clefts that are filled with amorphous debris seen on muscle biopsy 1 / 7739
27
 (HPO:0003674) Onset 32 / 7739
28
 (OMIM) Cervical muscle weakness 1 / 7739
29
 (OMIM) Thickened endplate basal lamina seen on muscle biopsy 1 / 7739
30
 (OMIM) Absence of acetylcholine receptor (AChR) autoantibodies 8 / 7739
31
 (HPO:0000007) Autosomal recessive inheritance 2538 / 7739
32
 (OMIM) Electrophysiologic studies show repetitive compound muscle action potentials (CMAP) in response to single stimulus 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Congenital myasthenic syndromes are genetic disorders of the neuromuscular junction that can be classified by the site of the transmission defect: presynaptic, synaptic, and postsynaptic. SCCMS is an autosomal dominant form of postsynaptic CMS. For a discussion of ...
Clinical Description OMIM Engel et al. (1982) reported 5 patients from 2 families and 1 sporadic patient who had a congenital myasthenic syndrome characterized by selective involvement of cervical, scapular, and finger extensor muscles and ophthalmoparesis from infancy or early childhood. ...
Molecular genetics OMIM In a patient with SCCMS, Ohno et al. (1995) identified a mutation in the CHRNE gene (100725.0001) that resulted in prolonged channel opening. In a patient with SCCMS, Engel et al. (1996) identified a mutation in the CHRNE ...