rs1555851550

Variant names:

• chr20-63408517-G-A
• rs1555851550
• NM_172107.4:c.1783C>T

Your query was ambiguous. Multiple possible variants found:

• chr20-63408517-G-A
• chr20-63408517-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_172107.4(KCNQ2):​c.1783C>T​(p.Arg595Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ2 NM_172107.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3 O:1
• Conservation: PhyloP100: 2.36
• Publications: 0 publications found

Genes affected

KCNQ2 (HGNC:6296): (potassium voltage-gated channel subfamily Q member 2) The M channel is a slowly activating and deactivating potassium channel that plays a critical role in the regulation of neuronal excitability. The M channel is formed by the association of the protein encoded by this gene and a related protein encoded by the KCNQ3 gene, both integral membrane proteins. M channel currents are inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 1 (BFNC), also known as epilepsy, benign neonatal type 1 (EBN1). At least five transcript variants encoding five different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

KCNQ2 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 7

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
• neonatal encephalopathy with non-epileptic myoclonus

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• neonatal-onset developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• seizures, benign familial neonatal, 1

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• seizures, benign familial neonatal, 2

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• benign familial infantile epilepsy

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

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• malignant migrating partial seizures of infancy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the KCNQ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 319 curated pathogenic missense variants (we use a threshold of 10). The gene has 78 curated benign missense variants. Gene score misZ: 4.0411 (above the threshold of 3.09). Trascript score misZ: 3.6968 (above the threshold of 3.09). GenCC associations: The gene is linked to benign familial infantile epilepsy, malignant migrating partial seizures of infancy, developmental and epileptic encephalopathy, 7, benign familial neonatal-infantile seizures, benign neonatal seizures, neonatal-onset developmental and epileptic encephalopathy, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, seizures, benign familial neonatal, 1, neonatal encephalopathy with non-epileptic myoclonus.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.894

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_172107.4. 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
	KCNQ2	NM_172107.4	MANE Select	c.1783C>T	p.Arg595Trp	missense	Exon 16 of 17	NP_742105.1
	KCNQ2	NM_001382235.1		c.1837C>T	p.Arg613Trp	missense	Exon 16 of 17	NP_001369164.1
	KCNQ2	NM_172106.3		c.1729C>T	p.Arg577Trp	missense	Exon 15 of 16	NP_742104.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.1783C>T	p.Arg595Trp	missense	Exon 16 of 17	ENSP00000352035.2
	KCNQ2	ENST00000626839.2	TSL:1	c.1729C>T	p.Arg577Trp	missense	Exon 15 of 16	ENSP00000486706.1
	KCNQ2	ENST00000344462.8	TSL:1	c.1690C>T	p.Arg564Trp	missense	Exon 15 of 16	ENSP00000339611.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	2	-	not provided (2)
-	1	-	Developmental and epileptic encephalopathy (1)
-	-	-	Seizures, benign familial neonatal, 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.20
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Benign	0.39	T
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.7	M
PhyloP100		2.4
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.75
MutPred		0.71		Loss of disorder (P = 0.0011)
MVP		0.86
MPC		1.6
ClinPred		0.96	D
GERP RS		3.9
Varity_R		0.78
gMVP		0.93
Mutation Taster		=2/98	disease causing (ClinVar)

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: rs1555851550; hg19: chr20-62039870; COSMIC: COSV60542078; COSMIC: COSV60542078;