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UniProtKB/Swiss-Prot Q9UQD0: Variant p.Val891Met

Sodium channel protein type 8 subunit alpha
Gene: SCN8A
Variant information

Variant position:  891
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 Valine (V) to Methionine (M) at position 891 (V891M, p.Val891Met).
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:  Similar physico-chemical property. Both residues are medium size and hydrophobic.
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:  Epileptic encephalopathy, early infantile, 13 (EIEE13) [MIM:614558]: A form of epilepsy characterized by frequent tonic seizures or spasms beginning in infancy with a specific EEG finding of suppression-burst patterns, characterized by high-voltage bursts alternating with almost flat suppression phases. Patients may progress to West syndrome, which is characterized by tonic spasms with clustering, arrest of psychomotor development, and hypsarrhythmia on EEG. EIEE13 is a severe form consisting of early-onset seizures, features of autism, intellectual disability, ataxia, and sudden unexplained death in epilepsy. {ECO:0000269|PubMed:22365152, ECO:0000269|PubMed:23708187, ECO:0000269|PubMed:24352161, ECO:0000269|PubMed:24874546, ECO:0000269|PubMed:24888894, ECO:0000269|PubMed:25239001, ECO:0000269|PubMed:25568300, ECO:0000269|PubMed:25725044, ECO:0000269|PubMed:25785782, ECO:0000269|PubMed:25818041, ECO:0000269|PubMed:26900580, ECO:0000269|PubMed:26993267, ECO:0000269|PubMed:27210545, ECO:0000269|PubMed:27864847, ECO:0000269|PubMed:28923014}. 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 EIEE13.
Any additional useful information about the variant.



Sequence information

Variant position:  891
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1980
The length of the canonical sequence.

Location on the sequence:   SVGALGNLTLVLAIIVFIFA  V VGMQLFGKSYKECVCKINQD
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                         SVGALGNLTLVLAIIVFIFAVVGMQLFGKSYKECVCKINQD

Mouse                         SVGALGNLTLVLAIIVFIFAVVGMQLFGKSYKECVCKISQE

Rat                           SVGALGNLTLVLAIIVFIFAVVGMQLFGKSYKECVCKINQE

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 – 1980 Sodium channel protein type 8 subunit alpha
Transmembrane 874 – 892 Helical; Name=S5 of repeat II
Repeat 735 – 1007 II
Disulfide bond 904 – 904 Interchain; with SCN2B or SCN4B
Disulfide bond 904 – 904 Interchain; with the conotoxin GVIIJ (when the channel is not linked to SCN2B or SCN4B; the bond to SCN2B or SCN4B protects the channel from the inhibition by toxin)


Literature citations

SCN8A mutations in Chinese patients with early onset epileptic encephalopathy and benign infantile seizures.
Wang J.; Gao H.; Bao X.; Zhang Q.; Li J.; Wei L.; Wu X.; Chen Y.; Yu S.;
BMC Med. Genet. 18:104-104(2017)
Cited for: VARIANTS EIEE13 PRO-232; GLU-850; MET-891; ARG-1475; ALA-1598; TRP-1872 AND SER-1877;

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.