8-132129923-T-G

Variant names:

• chr8-132129923-T-G
• rs554833870
• NM_004519.4:c.1958A>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The ENST00000388996.10(KCNQ3):​c.1958A>C​(p.Gln653Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,220 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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. Q653R) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: KCNQ3 ENST00000388996.10 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.66
• 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):

• seizures, benign familial neonatal, 2

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.35371915).

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000388996.10. 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
	KCNQ3	NM_004519.4	MANE Select	c.1958A>C	p.Gln653Pro	missense	Exon 15 of 15	NP_004510.1
	KCNQ3	NM_001204824.2		c.1598A>C	p.Gln533Pro	missense	Exon 15 of 15	NP_001191753.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ3	ENST00000388996.10	TSL:1 MANE Select	c.1958A>C	p.Gln653Pro	missense	Exon 15 of 15	ENSP00000373648.3
	KCNQ3	ENST00000519445.5	TSL:5	c.1922A>C	p.Gln641Pro	missense	Exon 15 of 15	ENSP00000428790.1
	KCNQ3	ENST00000521134.6	TSL:2	c.1598A>C	p.Gln533Pro	missense	Exon 15 of 15	ENSP00000429799.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152220 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251472 AF XY: 0.00000736

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152220 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74368

African (AFR) AF: 0.0000241 AC: 1 AN: 41458

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68048

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00000403 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Benign neonatal seizures (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.078
BayesDel_addAF	Uncertain	0.018	T
BayesDel_noAF	Uncertain	-0.030
CADD	Benign	16
DANN	Benign	0.95
DEOGEN2	Benign	0.24	T
Eigen	Benign	-0.57
Eigen_PC	Benign	-0.41
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.79	T
M_CAP	Uncertain	0.21	D
MetaRNN	Benign	0.35	T
MetaSVM	Uncertain	0.55	D
MutationAssessor	Benign	1.6	L
PhyloP100		1.7
PrimateAI	Benign	0.26	T
PROVEAN	Benign	2.3	N
REVEL	Uncertain	0.49
Sift	Benign	0.15	T
Sift4G	Benign	0.48	T
Polyphen		0.044	B
Vest4		0.32
MVP		0.50
MPC		0.17
ClinPred		0.34	T
GERP RS		4.6
Varity_R		0.11
gMVP		0.50
Mutation Taster		=82/18	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: rs554833870; hg19: chr8-133142170;