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UniProtKB/Swiss-Prot Q99250: Variant p.Thr218Lys

Sodium channel protein type 2 subunit alpha
Gene: SCN2A
Chromosomal location: 2q23-q24
Variant information

Variant position:  218
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Unclassified
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 Threonine (T) to Lysine (K) at position 218 (T218K, p.Thr218Lys).
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 medium size and polar (T) to large size and basic (K)
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, 11 (EIEE11) [MIM:613721]: An autosomal dominant seizure disorder characterized by neonatal or infantile onset of refractory seizures with resultant delayed neurologic development and persistent neurologic abnormalities. Patients may progress to West syndrome, which is characterized by tonic spasms with clustering, arrest of psychomotor development, and hypsarrhythmia on EEG. {ECO:0000269|PubMed:19783390, ECO:0000269|PubMed:19786696, ECO:0000269|PubMed:20956790, ECO:0000269|PubMed:22677033, ECO:0000269|PubMed:23033978, ECO:0000269|PubMed:23195492, ECO:0000269|PubMed:23550958, ECO:0000269|PubMed:23662938, ECO:0000269|PubMed:23708187, ECO:0000269|PubMed:23935176, ECO:0000269|PubMed:23988467, ECO:0000269|PubMed:24463883, ECO:0000269|PubMed:24579881, ECO:0000269|PubMed:24659627, ECO:0000269|PubMed:24710820, ECO:0000269|PubMed:25457084, ECO:0000269|PubMed:25818041, ECO:0000269|PubMed:26138355, ECO:0000269|PubMed:26291284, ECO:0000269|PubMed:26993267, ECO:0000269|PubMed:27864847}. 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 EIEE11; unknown pathological significance.
Any additional useful information about the variant.



Sequence information

Variant position:  218
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  2005
The length of the canonical sequence.

Location on the sequence:   VITFAYVTEFVDLGNVSALR  T FRVLRALKTISVIPGLKTIV
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                         VITFAYVTEFVDLGNVSALRTFRVLRALKTISVIPGLKTIV

Rat                           VITFAYVTEFVNLGNVSALRTFRVLRALKTISVIPGLKTIV

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 – 2005 Sodium channel protein type 2 subunit alpha
Transmembrane 215 – 231 Helical; Name=S4 of repeat I
Repeat 111 – 456 I
Glycosylation 212 – 212 N-linked (GlcNAc...) asparagine
Alternative sequence 209 – 209 D -> N. In isoform 2.


Literature citations

SCN2A encephalopathy: A major cause of epilepsy of infancy with migrating focal seizures.
Howell K.B.; McMahon J.M.; Carvill G.L.; Tambunan D.; Mackay M.T.; Rodriguez-Casero V.; Webster R.; Clark D.; Freeman J.L.; Calvert S.; Olson H.E.; Mandelstam S.; Poduri A.; Mefford H.C.; Harvey A.S.; Scheffer I.E.;
Neurology 85:958-966(2015)
Cited for: VARIANTS EIEE11 ILE-136; LYS-218; LEU-856; ASN-905; CYS-928; ARG-1593; VAL-1634 AND GLN-1882; VARIANT BFIS3 SER-240; VARIANT LYS-976;

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.