8-132132254-A-T

Variant names:

• chr8-132132254-A-T
• rs1060500606
• NM_004519.4:c.1810T>A

Variant summary

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

The NM_004519.4(KCNQ3):​c.1810T>A​(p.Tyr604Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,942 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y604C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNQ3 NM_004519.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.37
• Publications: 1 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 2 ACMG points.

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

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.1810T>A	p.Tyr604Asn	missense	Exon 14 of 15	NP_004510.1	O43525-1
	KCNQ3	NM_001204824.2		c.1450T>A	p.Tyr484Asn	missense	Exon 14 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.1810T>A	p.Tyr604Asn	missense	Exon 14 of 15	ENSP00000373648.3	O43525-1
	KCNQ3	ENST00000519445.5	TSL:5	c.1774T>A	p.Tyr592Asn	missense	Exon 14 of 15	ENSP00000428790.1	E7ET42
	KCNQ3	ENST00000521134.6	TSL:2	c.1450T>A	p.Tyr484Asn	missense	Exon 14 of 15	ENSP00000429799.1	O43525-2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459942 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726504

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33430

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39674

South Asian (SAS) AF: 0.00 AC: 0 AN: 86208

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110306

Other (OTH) AF: 0.00 AC: 0 AN: 60308

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Benign neonatal seizures (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.76	D
Eigen	Uncertain	0.44
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.27	D
MetaRNN	Uncertain	0.63	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.3	M
PhyloP100		8.4
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-0.92	N
REVEL	Uncertain	0.56
Sift	Benign	0.091	T
Sift4G	Benign	0.17	T
Polyphen		0.99	D
Vest4		0.61
MutPred		0.36		Loss of phosphorylation at Y604 (P = 0.0228)
MVP		0.66
MPC		0.61
ClinPred		0.89	D
GERP RS		5.7
Varity_R		0.17
gMVP		0.59
Mutation Taster		=49/51	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: rs1060500606; hg19: chr8-133144501;