NM_001165963.4(SCN1A):c.3661G>C (p.Glu1221Gln) AND Early infantile epileptic encephalopathy with suppression bursts

Clinical significance:Uncertain significance (Last evaluated: Nov 25, 2019)

Review status:1 star out of maximum of 4 stars

criteria provided, single submitter

Based on:
1 submission [Details]
Record status:

Allele description [Variation Report for NM_001165963.4(SCN1A):c.3661G>C (p.Glu1221Gln)]

NM_001165963.4(SCN1A):c.3661G>C (p.Glu1221Gln)

SCN1A:sodium voltage-gated channel alpha subunit 1 [Gene - OMIM - HGNC]
LOC102724058:uncharacterized LOC102724058 [Gene]
Variant type:
single nucleotide variant
Cytogenetic location:
Genomic location:
Preferred name:
NM_001165963.4(SCN1A):c.3661G>C (p.Glu1221Gln)
  • NC_000002.12:g.166013788C>G
  • NG_011906.1:g.64852G>C
  • NM_001165963.4:c.3661G>CMANE SELECT
  • NM_001165963.4:c.3661G>C
  • NM_001165964.3:c.3577G>C
  • NM_001202435.3:c.3661G>C
  • NM_001353948.2:c.3661G>C
  • NM_001353949.2:c.3628G>C
  • NM_001353950.2:c.3628G>C
  • NM_001353951.2:c.3628G>C
  • NM_001353952.2:c.3628G>C
  • NM_001353954.2:c.3625G>C
  • NM_001353955.2:c.3625G>C
  • NM_001353957.2:c.3577G>C
  • NM_001353958.2:c.3577G>C
  • NM_001353960.2:c.3574G>C
  • NM_001353961.2:c.1219G>C
  • NM_006920.6:c.3628G>C
  • NP_001159435.1:p.Glu1221Gln
  • NP_001159436.1:p.Glu1193Gln
  • NP_001189364.1:p.Glu1221Gln
  • NP_001340877.1:p.Glu1221Gln
  • NP_001340878.1:p.Glu1210Gln
  • NP_001340879.1:p.Glu1210Gln
  • NP_001340880.1:p.Glu1210Gln
  • NP_001340881.1:p.Glu1210Gln
  • NP_001340883.1:p.Glu1209Gln
  • NP_001340884.1:p.Glu1209Gln
  • NP_001340886.1:p.Glu1193Gln
  • NP_001340887.1:p.Glu1193Gln
  • NP_001340889.1:p.Glu1192Gln
  • NP_001340890.1:p.Glu407Gln
  • NP_008851.3:p.Glu1210Gln
  • LRG_8:g.64852G>C
  • NC_000002.11:g.166870298C>G
  • NM_001165963.1:c.3661G>C
  • NR_148667.2:n.4014G>C
Protein change:
dbSNP: rs794726854
NCBI 1000 Genomes Browser:
Molecular consequence:
  • NM_001165963.4:c.3661G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001165964.3:c.3577G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001202435.3:c.3661G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353948.2:c.3661G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353949.2:c.3628G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353950.2:c.3628G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353951.2:c.3628G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353952.2:c.3628G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353954.2:c.3625G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353955.2:c.3625G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353957.2:c.3577G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353958.2:c.3577G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353960.2:c.3574G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_001353961.2:c.1219G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NM_006920.6:c.3628G>C - missense variant - [Sequence Ontology: SO:0001583]
  • NR_148667.2:n.4014G>C - non-coding transcript variant - [Sequence Ontology: SO:0001619]


Early infantile epileptic encephalopathy with suppression bursts (EIEE)
Early infantile epileptic encephalopathy; Ohtahara syndrome; Developmental and epileptic encephalopathy
MONDO: MONDO:0100062; MedGen: C0393706; Orphanet: 1934; OMIM: PS308350

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Assertion and evidence details

Submission AccessionSubmitterReview Status
(Assertion method)
Clinical Significance
(Last evaluated)
SCV001198783Invitaecriteria provided, single submitter
Uncertain significance
(Nov 25, 2019)
germlineclinical testing

PubMed (1)
[See all records that cite this PMID]

Summary from all submissions

EthnicityOriginAffectedIndividualsFamiliesChromosomes testedNumber TestedFamily historyMethod
not providedgermlineunknownnot providednot providednot providednot providednot providedclinical testing



Sherloc: a comprehensive refinement of the ACMG-AMP variant classification criteria.

Nykamp K, Anderson M, Powers M, Garcia J, Herrera B, Ho YY, Kobayashi Y, Patil N, Thusberg J, Westbrook M; Invitae Clinical Genomics Group., Topper S.

Genet Med. 2017 Oct;19(10):1105-1117. doi: 10.1038/gim.2017.37. Epub 2017 May 11. Erratum in: Genet Med. 2020 Jan;22(1):240-242.

PubMed [citation]

Details of each submission

From Invitae, SCV001198783.2

#EthnicityIndividualsChromosomes TestedFamily HistoryMethodCitations
1not providednot providednot providednot providedclinical testing PubMed (1)


This sequence change replaces glutamic acid with glutamine at codon 1221 of the SCN1A protein (p.Glu1221Gln). The glutamic acid residue is highly conserved and there is a small physicochemical difference between glutamic acid and glutamine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with SCN1A-related conditions. ClinVar contains an entry for this variant (Variation ID: 190031). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

OriginAffectedNumber testedTissuePurposeMethodIndividualsAllele frequencyFamiliesCo-occurrences
1germlineunknownnot providednot providednot providednot providednot providednot providednot provided

Last Updated: Nov 27, 2021

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