NM_020822.3:c.1139C>G

Variant names:

• chr9-135765134-C-G
• rs765193021
• NM_020822.3:c.1139C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_020822.3(KCNT1):​c.1139C>G​(p.Ser380Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S380F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNT1 NM_020822.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.44
• Publications: 0 publications found

Genes affected

KCNT1 (HGNC:18865): (potassium sodium-activated channel subfamily T member 1) Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a sodium-activated potassium channel subunit which is thought to function in ion conductance and developmental signaling pathways. Mutations in this gene cause the early-onset epileptic disorders, malignant migrating partial seizures of infancy and autosomal dominant nocturnal frontal lobe epilepsy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2012]

KCNT1 Gene-Disease associations (from GenCC):

• childhood-onset epilepsy syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 14

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• malignant migrating partial seizures of infancy

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
• autosomal dominant nocturnal frontal lobe epilepsy 5

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nocturnal frontal lobe epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3	c.1139C>G	p.Ser380Cys	missense_variant	Exon 12 of 31	ENST00000371757.7	NP_065873.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7	c.1139C>G	p.Ser380Cys	missense_variant	Exon 12 of 31	1	NM_020822.3	ENSP00000360822.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.086
BayesDel_addAF	Benign	-0.031	T
BayesDel_noAF	Benign	-0.28
CADD	Uncertain	26
DANN	Uncertain	0.98
DEOGEN2	Benign	0.31	.;.;.;.;.;.;.;.;T;.
Eigen	Benign	0.0048
Eigen_PC	Benign	0.17
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;D;D;D;D;D;D;D
M_CAP	Benign	0.0072	T
MetaRNN	Uncertain	0.68	D;D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.4	.;.;.;.;.;.;.;.;L;.
PhyloP100		7.4
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-2.2	.;.;N;N;.;.;.;.;N;N
REVEL	Benign	0.20
Sift	Benign	0.066	.;.;T;T;.;.;.;.;T;T
Sift4G	Benign	0.14	T;T;T;T;T;T;T;T;T;T
Polyphen		0.0010	.;.;.;.;.;.;.;.;B;.
Vest4		0.82
MutPred		0.51		.;.;.;.;.;.;Gain of catalytic residue at L362 (P = 0.0135);Gain of catalytic residue at L362 (P = 0.0135);Gain of catalytic residue at L362 (P = 0.0135);Gain of catalytic residue at L362 (P = 0.0135);
MVP		0.53
MPC		0.64
ClinPred		0.90	D
GERP RS		4.3
Varity_R		0.30
gMVP		0.96
Mutation Taster		=52/48	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs765193021; hg19: chr9-138656980;