8-132141191-T-A

Variant names:

• chr8-132141191-T-A
• rs118192252
• NM_004519.4:c.1403A>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_004519.4(KCNQ3):​c.1403A>T​(p.Asn468Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 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. N468S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNQ3 NM_004519.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.93
• Publications: 0 publications found

Genes affected

KCNQ3 (HGNC:6297): (potassium voltage-gated channel subfamily Q member 3) This gene encodes a protein that functions in the regulation of neuronal excitability. The encoded protein forms an M-channel by associating with the products of the related KCNQ2 or KCNQ5 genes, which both encode integral membrane proteins. M-channel currents are inhibited by M1 muscarinic acetylcholine receptors and are activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 2 (BFNC2), also known as epilepsy, benign neonatal type 2 (EBN2). Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2014]

KCNQ3 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• seizures, benign familial neonatal, 2

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• self-limited familial neonatal epilepsy

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• benign familial infantile epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• benign neonatal seizures

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• genetic developmental and epileptic encephalopathy

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics, ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.832

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004519.4. 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
	KCNQ3	NM_004519.4	MANE Select	c.1403A>T	p.Asn468Ile	missense	Exon 10 of 15	NP_004510.1	O43525-1
	KCNQ3	NM_001204824.2		c.1043A>T	p.Asn348Ile	missense	Exon 10 of 15	NP_001191753.1	O43525-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ3	ENST00000388996.10	TSL:1 MANE Select	c.1403A>T	p.Asn468Ile	missense	Exon 10 of 15	ENSP00000373648.3	O43525-1
	KCNQ3	ENST00000519445.5	TSL:5	c.1403A>T	p.Asn468Ile	missense	Exon 10 of 15	ENSP00000428790.1	E7ET42
	KCNQ3	ENST00000521134.6	TSL:2	c.1043A>T	p.Asn348Ile	missense	Exon 10 of 15	ENSP00000429799.1	O43525-2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.83	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		3.9
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-4.2	D
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.030	D
Polyphen		0.97	D
Vest4		0.73
MutPred		0.57		Loss of disorder (P = 0.0251)
MVP		0.91
MPC		2.1
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.81
gMVP		0.74
Mutation Taster		=57/43	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: rs118192252; hg19: chr8-133153438;