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UniProtKB/Swiss-Prot P35498: Variant p.Ile227Ser

Sodium channel protein type 1 subunit alpha
Gene: SCN1A
Variant information

Variant position:  227
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  LP/P [Disclaimer]
The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance

Residue change:  From Isoleucine (I) to Serine (S) at position 227 (I227S, p.Ile227Ser).
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 hydrophobic (I) to small size and polar (S)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -2
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

Variant description:  In DRVT; borderline phenotype with spike wave activity in some patients; results in a non-functional channel.
Any additional useful information about the variant.

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



Sequence information

Variant position:  227
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  2009
The length of the canonical sequence.

Location on the sequence:   VDLGNVSALRTFRVLRALKT  I SVIPGLKTIVGALIQSVKKL
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                         VDLGNVSALRTFRVLRALKTISVIPGLKTIVGALIQSVKKL

Mouse                         VDLGNVSALRTFRVLRALKTISVIPGLKTIVGALIQSVKKL

Rat                           VDLGNVSALRTFRVLRALKTISVIPGLKTIVGALIQSVKKL

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 – 2009 Sodium channel protein type 1 subunit alpha
Transmembrane 214 – 230 Helical; Name=S4 of repeat I
Repeat 110 – 454 I
Glycosylation 211 – 211 N-linked (GlcNAc...) asparagine


Literature citations

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy.
Nabbout R.; Gennaro E.; Dalla Bernardina B.; Dulac O.; Madia F.; Bertini E.; Capovilla G.; Chiron C.; Cristofori G.; Elia M.; Fontana E.; Gaggero R.; Granata T.; Guerrini R.; Loi M.; La Selva L.; Lispi M.L.; Matricardi A.; Romeo A.; Tzolas V.; Valseriati D.; Veggiotti P.; Vigevano F.; Vallee L.; Dagna Bricarelli F.; Bianchi A.; Zara F.;
Neurology 60:1961-1967(2003)
Cited for: VARIANTS DRVT ASP-78; GLU-177; SER-227; ARG-280; ILE-297; ASN-426; ARG-1233; ILE-1461; SER-1463; ALA-1668; THR-1780 AND 1812-TRP--LYS-1815 DELINS CYS;

Familial occurrence of febrile seizures and epilepsy in severe myoclonic epilepsy of infancy (SMEI) patients with SCN1A mutations.
Mancardi M.M.; Striano P.; Gennaro E.; Madia F.; Paravidino R.; Scapolan S.; Dalla Bernardina B.; Bertini E.; Bianchi A.; Capovilla G.; Darra F.; Elia M.; Freri E.; Gobbi G.; Granata T.; Guerrini R.; Pantaleoni C.; Parmeggiani A.; Romeo A.; Santucci M.; Vecchi M.; Veggiotti P.; Vigevano F.; Pistorio A.; Gaggero R.; Zara F.;
Epilepsia 47:1629-1635(2006)
Cited for: VARIANTS DRVT ASP-78; PRO-162; ASN-194; LYS-217; SER-227; ARG-280; LEU-383; CYS-393; SER-393; ASN-426; ARG-812; LYS-846; PRO-942; ARG-1233; GLN-1245; CYS-1422; ARG-1426; LEU-1451; SER-1463; SER-1475; ALA-1668; ARG-1714; GLU-1762; PHE-1773 AND THR-1780;

Nonfunctional SCN1A is common in severe myoclonic epilepsy of infancy.
Ohmori I.; Kahlig K.M.; Rhodes T.H.; Wang D.W.; George A.L. Jr.;
Epilepsia 47:1636-1642(2006)
Cited for: CHARACTERIZATION OF VARIANTS DRVT GLU-177; SER-227; HIS-393; ASN-426; GLN-939; ARG-959; PHE-1289 DEL AND ILE-1909;

Spectrum of SCN1A gene mutations associated with Dravet syndrome: analysis of 333 patients.
Depienne C.; Trouillard O.; Saint-Martin C.; Gourfinkel-An I.; Bouteiller D.; Carpentier W.; Keren B.; Abert B.; Gautier A.; Baulac S.; Arzimanoglou A.; Cazeneuve C.; Nabbout R.; LeGuern E.;
J. Med. Genet. 46:183-191(2009)
Cited for: VARIANTS GLN-542; HIS-604; THR-924; ILE-1079; THR-1109; ASP-1308; CYS-1575 AND GLY-1928; VARIANTS DRVT VAL-58; PHE-61; HIS-79; GLN-101; TRP-101; ASN-124; ARG-171; VAL-175; LYS-191; TYR-191; GLY-194; GLU-223; SER-227; SER-232; TYR-243; ARG-277; LEU-281; SER-281; ILE-322; PHE-340; ASP-343; ARG-345; ASP-355; ILE-357; GLN-378; CYS-393; MET-400 DEL; CYS-426; PHE-525; GLY-626; ARG-843; CYS-859; LYS-875; LEU-896; PHE-927; CYS-931; ILE-934; PRO-939; ASN-943; SER-949; TYR-949; LYS-973; PRO-986; GLY-998; LYS-1068; GLY-1239; TYR-1239; ASP-1255; VAL-1275; SER-1284; PHE-1289 DEL; SER-1316; PRO-1328; LYS-1367; SER-1391; GLY-1416; ILE-1431; MET-1437; PHE-1473 DEL; ILE-1483 DEL; GLY-1484; ILE-1538; ALA-1544; LYS-1561; GLU-1579; GLU-1586; CYS-1596; LEU-1596; ILE-1612; GLY-1639; HIS-1648; ARG-1658; MET-1658; LYS-1664; ARG-1675; PHE-1677; LYS-1714; CYS-1725; ASN-1771; THR-1780; HIS-1781; MET-1782; SER-1782; THR-1783; VAL-1783; LYS-1788; ILE-1808; SER-1812; 1813-GLU--PHE-1815 DEL AND PHE-1835;

De novo SCN1A mutations in Dravet syndrome and related epileptic encephalopathies are largely of paternal origin.
Heron S.E.; Scheffer I.E.; Iona X.; Zuberi S.M.; Birch R.; McMahon J.M.; Bruce C.M.; Berkovic S.F.; Mulley J.C.;
J. Med. Genet. 47:137-141(2010)
Cited for: VARIANTS DRVT CYS-84; GLN-101; LYS-171; THR-175; ASN-194; SER-227; PHE-406; ASN-413; PRO-783; GLU-944; LEU-945; HIS-946; GLU-950; GLY-1396; LYS-1450; VAL-1545; GLN-1645; ARG-1726 AND THR-1783; VARIANTS HIS-604; GLN-1636 AND HIS-1657;

Genotype-phenotype associations in SCN1A-related epilepsies.
Zuberi S.M.; Brunklaus A.; Birch R.; Reavey E.; Duncan J.; Forbes G.H.;
Neurology 76:594-600(2011)
Cited for: VARIANTS DRVT PHE-17 DEL; THR-68; ASN-79; CYS-84; PRO-98; GLN-101; TRP-101; ARG-108; ASP-127; ARG-199; SER-227; THR-227; SER-232; ARG-233; VAL-342; ASP-343; TRP-351; SER-359; ARG-363; ARG-384; CYS-393; HIS-393; VAL-400; VAL-403; PHE-406; GLY-626; ASP-762; THR-785; ILE-812; ARG-842; 854-GLY-LEU-855 DEL; CYS-859; GLN-862; PRO-890; CYS-932; PRO-933; CYS-946; HIS-946; ARG-950; LYS-954; LYS-956; LEU-957; ILE-976; VAL-979; ARG-993; 999-ASN-LEU-1000 DELINS LEU-ILE-SER; LYS-1208; LYS-1221; PHE-1230; ASP-1238; ALA-1266; ASN-1288; VAL-1320; PRO-1326; GLY-1350; ARG-1358; PRO-1370; HIS-1378; THR-1378; ILE-1394; TYR-1396; SER-1417; PHE-1423; ALA-1429 DEL; VAL-1433; LYS-1450; SER-1451; LYS-1454; HIS-1462; LYS-1476; LYS-1503; GLY-1544; GLU-1586; ARG-1588; HIS-1592; PRO-1592; SER-1605; GLU-1637; THR-1638; CYS-1648; GLU-1653; PRO-1660; PRO-1667; LEU-1668; ILE-1672; THR-1673; THR-1683; ASP-1684; TRP-1688; ARG-1714; ASN-1763; ASN-1770; PHE-1770; THR-1770; THR-1780; VAL-1783; LYS-1787; PRO-1832; LYS-1852; LEU-1855; GLU-1880; THR-1909 DEL AND ARG-1927 DELINS ILE-ILE-GLN; VARIANTS GEFS+2 LEU-218; ILE-254; GLY-291; THR-960; VAL-973; SER-1204; PHE-1230; ASP-1414; HIS-1596; LEU-1739 AND THR-1867; VARIANTS ASN-45; VAL-333; ASN-382; HIS-604; ILE-699; THR-924; HIS-931; GLU-1006; ILE-1079; THR-1109; ASP-1308; ASP-1326; MET-1483 AND PHE-1683;

Prevalence of SCN1A mutations in children with suspected Dravet syndrome and intractable childhood epilepsy.
Wang J.W.; Shi X.Y.; Kurahashi H.; Hwang S.K.; Ishii A.; Higurashi N.; Kaneko S.; Hirose S.;
Epilepsy Res. 102:195-200(2012)
Cited for: VARIANTS DRVT CYS-84; GLN-101; TRP-101; ILE-105; ARG-179; ARG-190; ARG-226; SER-227; ARG-259; ARG-280; ALA-281; PRO-363; ARG-384; HIS-393; TRP-409; CYS-426; MET-875; ILE-876; PHE-896; ILE-934; PHE-940; CYS-946; HIS-946; LEU-987; GLY-1316; VAL-1339; MET-1344; PRO-1355; VAL-1385; GLY-1418; PRO-1427; CYS-1453; HIS-1462; SER-1472; TYR-1485; GLU-1503 DEL; LYS-1503; VAL-1545; ARG-1555; GLY-1608; LEU-1630; ASN-1638; SER-1642; VAL-1662; PRO-1667; PHE-1677; THR-1683; SER-1692; CYS-1694; GLY-1727; ARG-1741; PHE-1766 DEL; PHE-1771; THR-1783; VAL-1783 AND THR-1792; VARIANTS ICEGTC SER-90; GLN-101; SER-178; MET-252; ARG-290; HIS-393; ILE-896; ALA-944; GLN-1213; CYS-1254; THR-1325; PRO-1328; LEU-1357; ARG-1376; ASP-1429; HIS-1462; LYS-1511; VAL-1619; SER-1684; PRO-1724; CYS-1781 AND TRP-1861; VARIANTS GLN-542 AND CYS-1575;

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.