MCID: MYS065
MIFTS: 21

Myasthenic Syndrome, Congenital, 18

Categories: Genetic diseases, Neuronal diseases, Eye diseases, Rare diseases

Aliases & Classifications for Myasthenic Syndrome, Congenital, 18

MalaCards integrated aliases for Myasthenic Syndrome, Congenital, 18:

Name: Myasthenic Syndrome, Congenital, 18 57 75 29 6
Cms18 57 12 75
Myasthenic Syndrome, Congenital, 18, with Intellectual Disability and Ataxia 57
Myasthenic Syndrome, Congenital, 18 with Intellectual Disability and Ataxia 75
Myasthenic Syndrome, Congenital, Type 18 40
Congenital Myasthenic Syndrome 18 12

Characteristics:

OMIM:

57
Inheritance:
autosomal dominant

Miscellaneous:
onset in utero
one patient has been reported (last curated april 2015)


HPO:

32
myasthenic syndrome, congenital, 18:
Onset and clinical course congenital onset
Inheritance autosomal dominant inheritance


Classifications:



Summaries for Myasthenic Syndrome, Congenital, 18

UniProtKB/Swiss-Prot : 75 Myasthenic syndrome, congenital, 18: A form of congenital myasthenic syndrome, a group of disorders characterized by failure of neuromuscular transmission, including pre- synaptic, synaptic, and post-synaptic disorders that are not of autoimmune origin. Clinical features are easy fatigability and muscle weakness affecting the axial and limb muscles (with hypotonia in early-onset forms), the ocular muscles (leading to ptosis and ophthalmoplegia), and the facial and bulbar musculature (affecting sucking and swallowing, and leading to dysphonia). The symptoms fluctuate and worsen with physical effort. CMS18 is an autosomal dominant presynaptic disorder clinically characterized by early-onset muscle weakness and easy fatigability associated with delayed psychomotor development and ataxia.

MalaCards based summary : Myasthenic Syndrome, Congenital, 18, is also known as cms18. An important gene associated with Myasthenic Syndrome, Congenital, 18 is SNAP25 (Synaptosome Associated Protein 25). Related phenotypes are ptosis and ataxia

Disease Ontology : 12 A congenital myasthenic syndrome characterized by autosomal dominant inheritance of presynaptic neuromuscular junction defects, early-onset muscle weakness, easy fatigability, delayed psychomotor development and ataxia that has material basis in heterozygous mutation in the SNAP25 gene on chromosome 20p11.

OMIM : 57 Congenital myasthenic syndrome-18 is an autosomal dominant presynaptic neuromuscular disorder characterized by early-onset muscle weakness and easy fatigability associated with delayed psychomotor development and ataxia (summary by Shen et al., 2014). For a discussion of genetic heterogeneity of CMS, see CMS1A (601462). (616330)

Related Diseases for Myasthenic Syndrome, Congenital, 18

Symptoms & Phenotypes for Myasthenic Syndrome, Congenital, 18

Symptoms via clinical synopsis from OMIM:

57
Head And Neck Eyes:
ptosis

Muscle Soft Tissue:
muscle weakness
easy fatigability
decremental compound muscle action potential (cmap) in response to repetitive nerve stimulation
decreased spontaneous miniature endplate potentials (mepp)
decreased quantal release

Skeletal:
joint contractures

Respiratory:
respiratory insufficiency, neonatal

Neurologic Central Nervous System:
ataxia
dysarthria
difficulty walking
poor speech
delayed psychomotor development
more
Neurologic Peripheral Nervous System:
areflexia

Prenatal Manifestations Movement:
decreased fetal movements

Head And Neck Neck:
weak neck muscles


Clinical features from OMIM:

616330

Human phenotypes related to Myasthenic Syndrome, Congenital, 18:

32 (show all 12)
# Description HPO Frequency HPO Source Accession
1 ptosis 32 HP:0000508
2 ataxia 32 HP:0001251
3 dysarthria 32 HP:0001260
4 muscle weakness 32 HP:0001324
5 respiratory insufficiency 32 HP:0002093
6 global developmental delay 32 HP:0001263
7 flexion contracture 32 HP:0001371
8 areflexia 32 HP:0001284
9 difficulty walking 32 HP:0002355
10 decreased fetal movement 32 HP:0001558
11 poor speech 32 HP:0002465
12 easy fatigability 32 HP:0003388

Drugs & Therapeutics for Myasthenic Syndrome, Congenital, 18

Search Clinical Trials , NIH Clinical Center for Myasthenic Syndrome, Congenital, 18

Genetic Tests for Myasthenic Syndrome, Congenital, 18

Genetic tests related to Myasthenic Syndrome, Congenital, 18:

# Genetic test Affiliating Genes
1 Myasthenic Syndrome, Congenital, 18 29 SNAP25

Anatomical Context for Myasthenic Syndrome, Congenital, 18

Publications for Myasthenic Syndrome, Congenital, 18

Variations for Myasthenic Syndrome, Congenital, 18

UniProtKB/Swiss-Prot genetic disease variations for Myasthenic Syndrome, Congenital, 18:

75
# Symbol AA change Variation ID SNP ID
1 SNAP25 p.Ile67Asn VAR_073698

ClinVar genetic disease variations for Myasthenic Syndrome, Congenital, 18:

6
(show all 14)
# Gene Variation Type Significance SNP ID Assembly Location
1 SNAP25 NM_130811.3(SNAP25): c.200T> A (p.Ile67Asn) single nucleotide variant Pathogenic GRCh38 Chromosome 20, 10293197: 10293197
2 SNAP25 NM_130811.3(SNAP25): c.200T> A (p.Ile67Asn) single nucleotide variant Pathogenic GRCh37 Chromosome 20, 10273845: 10273845
3 SNAP25 NM_130811.3(SNAP25): c.366C> T (p.Asp122=) single nucleotide variant Likely benign rs377498338 GRCh38 Chromosome 20, 10297009: 10297009
4 SNAP25 NM_130811.3(SNAP25): c.366C> T (p.Asp122=) single nucleotide variant Likely benign rs377498338 GRCh37 Chromosome 20, 10277657: 10277657
5 SNAP25 NM_130811.3(SNAP25): c.552+9G> A single nucleotide variant Likely benign rs375161376 GRCh37 Chromosome 20, 10280069: 10280069
6 SNAP25 NM_130811.3(SNAP25): c.552+9G> A single nucleotide variant Likely benign rs375161376 GRCh38 Chromosome 20, 10299421: 10299421
7 SNAP25 NM_130811.3(SNAP25): c.553-4C> T single nucleotide variant Benign rs79020892 GRCh38 Chromosome 20, 10306125: 10306125
8 SNAP25 NM_130811.3(SNAP25): c.553-4C> T single nucleotide variant Benign rs79020892 GRCh37 Chromosome 20, 10286773: 10286773
9 SNAP25 NM_130811.3(SNAP25): c.-63-21820G> A single nucleotide variant Benign rs363050 GRCh37 Chromosome 20, 10234257: 10234257
10 SNAP25 NM_130811.3(SNAP25): c.-63-21820G> A single nucleotide variant Benign rs363050 GRCh38 Chromosome 20, 10253609: 10253609
11 SNAP25 NM_130811.3(SNAP25): c.6C> T (p.Ala2=) single nucleotide variant Likely benign rs11547858 GRCh38 Chromosome 20, 10275497: 10275497
12 SNAP25 NM_130811.3(SNAP25): c.6C> T (p.Ala2=) single nucleotide variant Likely benign rs11547858 GRCh37 Chromosome 20, 10256145: 10256145
13 SNAP25 NM_130811.3(SNAP25): c.462C> T (p.Ser154=) single nucleotide variant Likely benign rs201639889 GRCh37 Chromosome 20, 10279970: 10279970
14 SNAP25 NM_130811.3(SNAP25): c.462C> T (p.Ser154=) single nucleotide variant Likely benign rs201639889 GRCh38 Chromosome 20, 10299322: 10299322

Expression for Myasthenic Syndrome, Congenital, 18

Search GEO for disease gene expression data for Myasthenic Syndrome, Congenital, 18.

Pathways for Myasthenic Syndrome, Congenital, 18

GO Terms for Myasthenic Syndrome, Congenital, 18

Sources for Myasthenic Syndrome, Congenital, 18

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10 dbSNP
11 DGIdb
17 ExPASy
19 FMA
28 GO
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31 HMDB
32 HPO
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62 PubMed
64 QIAGEN
69 SNOMED-CT via HPO
70 SNOMED-CT via Orphanet
71 TGDB
72 Tocris
73 UMLS
74 UMLS via Orphanet
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