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UniProtKB/Swiss-Prot Q16572: Variant p.Gly186Ala

Vesicular acetylcholine transporter
Gene: SLC18A3
Variant information

Variant position:  186
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Glycine (G) to Alanine (A) at position 186 (G186A, p.Gly186Ala).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from glycine (G) to small size and hydrophobic (A)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  0
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Involvement in disease:  Myasthenic syndrome, congenital, 21, presynaptic (CMS21) [MIM:617239]: 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. CMS21 is an autosomal recessive, pre-synaptic form characterized by ptosis, ophthalmoplegia, fatigable weakness, apneic crises, and deterioration of symptoms in cold water. Learning difficulties and left ventricular dysfunction may be present in some patients. {ECO:0000269|PubMed:27590285}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In CMS21.
Any additional useful information about the variant.

Other resources:  
Links to websites of interest for the variant.



Sequence information

Variant position:  186
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  532
The length of the canonical sequence.

Location on the sequence:   TVLFAFAEDYATLFAARSLQ  G LGSAFADTSGIAMIADKYPE
The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

TypePositionsDescription
Chain 1 – 532 Vesicular acetylcholine transporter
Transmembrane 183 – 203 Helical


Literature citations

Variants in SLC18A3, vesicular acetylcholine transporter, cause congenital myasthenic syndrome.
O'Grady G.L.; Verschuuren C.; Yuen M.; Webster R.; Menezes M.; Fock J.M.; Pride N.; Best H.A.; Benavides Damm T.; Turner C.; Lek M.; Engel A.G.; North K.N.; Clarke N.F.; MacArthur D.G.; Kamsteeg E.J.; Cooper S.T.;
Neurology 87:1442-1448(2016)
Cited for: VARIANTS CMS21 ALA-186 AND HIS-398; INVOLVEMENT IN CMS21;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.