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UniProtKB/Swiss-Prot Q9NY46: Variant p.Arg357Gln

Sodium channel protein type 3 subunit alpha
Gene: SCN3A
Chromosomal location: 2q24
Variant information

Variant position:  357
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 Arginine (R) to Glutamine (Q) at position 357 (R357Q, p.Arg357Gln).
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 large size and basic (R) to medium size and polar (Q)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  1
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:  Epilepsy, familial focal, with variable foci 4 (FFEVF4) [MIM:617935]: An autosomal dominant form of epilepsy characterized by focal seizures arising from different cortical regions, including the temporal, frontal, parietal, and occipital lobes. Seizure types commonly include temporal lobe epilepsy, frontal lobe epilepsy, and nocturnal frontal lobe epilepsy. Some patients may have intellectual disability or autism spectrum disorders. Seizure onset usually occurs in the first or second decades, although later onset has been reported, and there is phenotypic variability within families. A subset of patients have structural brain abnormalities. Penetrance of the disorder is incomplete. FFEVF4 is characterized by onset of focal seizures in the first years of life. {ECO:0000269|PubMed:24157691, ECO:0000269|PubMed:28235671}. 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 FFEVF4; affects voltage-dependent sodium channel activity; smaller current density and slower activation compared to wild-type channels and increased current activation in response to depolarizing voltage ramps.
Any additional useful information about the variant.

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



Sequence information

Variant position:  357
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  2000
The length of the canonical sequence.

Location on the sequence:   CGNGSDAGQCPEGYICVKAG  R NPNYGYTSFDTFSWAFLSLF
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.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.

Human                         CGNGSDAGQCPEGYICVKAGRNPNYGYTSFDTFSWAFLSLF

Mouse                         CGNGSDAGQCPEGYICVKAGRNPNYGYTSFDTFSWAFLSLF

Rat                           CGNGSDAGQCPEGYICVKAGRNPNYGYTSFDTFSWAFLSLF

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 – 2000 Sodium channel protein type 3 subunit alpha
Topological domain 270 – 368 Extracellular
Repeat 110 – 455 I
Glycosylation 339 – 339 N-linked (GlcNAc...) asparagine


Literature citations

Novel SCN3A variants associated with focal epilepsy in children.
Vanoye C.G.; Gurnett C.A.; Holland K.D.; George A.L. Jr.; Kearney J.A.;
Neurobiol. Dis. 62:313-322(2014)
Cited for: INVOLVEMENT IN FFEVF4; FUNCTION; VARIANTS FFEVF4 GLN-357; ASN-815; LYS-1160 AND VAL-1372;

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.