chr9-135779468-A-G

Variant names:

• chr9-135779468-A-G
• rs1057519544
• NM_020822.3:c.2839A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PP3 PP5_Moderate

The NM_020822.3(KCNT1):​c.2839A>G​(p.Lys947Glu) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNT1 NM_020822.3 missense, splice_region
• Scores: Splicing: ADA: 0.07914
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 8.88
• Publications: 2 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: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_020822.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.75
• PP5: Variant 9-135779468-A-G is Pathogenic according to our data. Variant chr9-135779468-A-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 375526.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020822.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT1	NM_020822.3	MANE Select	c.2839A>G	p.Lys947Glu	missense splice_region	Exon 24 of 31	NP_065873.2
	KCNT1	NM_001272003.2		c.2704A>G	p.Lys902Glu	missense splice_region	Exon 23 of 31	NP_001258932.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNT1	ENST00000371757.7	TSL:1 MANE Select	c.2839A>G	p.Lys947Glu	missense splice_region	Exon 24 of 31	ENSP00000360822.2
	KCNT1	ENST00000460750.5	TSL:1	n.*2449A>G		splice_region non_coding_transcript_exon	Exon 24 of 32	ENSP00000418777.1
	KCNT1	ENST00000460750.5	TSL:1	n.*2449A>G		3_prime_UTR	Exon 24 of 32	ENSP00000418777.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Malignant migrating partial seizures of infancy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.85
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.75	D
MetaSVM	Uncertain	-0.026	T
MutationAssessor	Benign	1.8	L
PhyloP100		8.9
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-3.2	D
REVEL	Uncertain	0.64
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.0080	D
Polyphen		0.85	P
Vest4		0.88
MutPred		0.26		Loss of ubiquitination at K928 (P = 0.0059)
MVP		0.84
MPC		1.8
ClinPred		0.99	D
GERP RS		3.8
Varity_R		0.66
gMVP		0.97
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.079
dbscSNV1_RF	Benign	0.29
SpliceAI score (max)		0.020		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: rs1057519544; hg19: chr9-138671314;