NM_198503.5:c.3407G>T

Variant names:

• chr1-196228225-C-A
• rs760199544
• NM_198503.5:c.3407G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PM4

The NM_198503.5(KCNT2):​c.3407G>T​(p.Ter1136Leuext*?) variant causes a stop lost change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNT2 NM_198503.5 stop_lost
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.15
• Publications: 0 publications found

Genes affected

KCNT2 (HGNC:18866): (potassium sodium-activated channel subfamily T member 2) Enables chloride-activated potassium channel activity. Involved in potassium ion export across plasma membrane. Located in plasma membrane. Implicated in developmental and epileptic encephalopathy 57. [provided by Alliance of Genome Resources, Apr 2022]

KCNT2 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 57

  Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Stoplost variant in NM_198503.5 Downstream stopcodon found after 35 codons.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_198503.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT2	NM_198503.5	MANE Select	c.3407G>T	p.Ter1136Leuext*?	stop_lost	Exon 28 of 28	NP_940905.2
	KCNT2	NM_001287819.3		c.3335G>T	p.Ter1112Leuext*?	stop_lost	Exon 27 of 27	NP_001274748.1	Q6UVM3-2
	KCNT2	NM_001287820.3		c.3206G>T	p.Ter1069Leuext*?	stop_lost	Exon 27 of 27	NP_001274749.1	Q6UVM3-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT2	ENST00000294725.14	TSL:1 MANE Select	c.3407G>T	p.Ter1136Leuext*?	stop_lost	Exon 28 of 28	ENSP00000294725.8	Q6UVM3-1
	KCNT2	ENST00000367433.9	TSL:1	c.3335G>T	p.Ter1112Leuext*?	stop_lost	Exon 27 of 27	ENSP00000356403.5	Q6UVM3-2
	KCNT2	ENST00000609185.5	TSL:1	c.3206G>T	p.Ter1069Leuext*?	stop_lost	Exon 27 of 27	ENSP00000476657.1	Q6UVM3-3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 25

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.099	T
BayesDel_noAF	Benign	-0.38
CADD	Benign	13
DANN	Benign	0.81
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Uncertain	0.94	D
PhyloP100		3.1
Vest4		0.022
GERP RS		5.7
Mutation Taster		=43/57	disease causing

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: rs760199544; hg19: chr1-196197355;