Genetic Variant NM_172107.4:c.2252C>T (chr20-63407011-G-A) – ACMG Classification: Likely_benign (-6 pts)

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 3P and 9B. PM5PP2BP4BS1BS2

The NM_172107.4(KCNQ2):c.2252C>T(p.Ser751Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000952 in 1,533,154 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. S751A) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000099 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000095 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 9.27

Publications

1 publications found

Variant links:

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
undetermined early-onset epileptic encephalopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
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

KCNQ2 links:

Genome browser will be placed here

new If you want to explore the variant's impact on the transcript NM_172107.4, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr20-63407012-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3248555.Status of the report is no_assertion_criteria_provided, 0 stars.

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 complex neurodevelopmental disorder, developmental and epileptic encephalopathy, 7, neonatal encephalopathy with non-epileptic myoclonus, benign familial infantile epilepsy, malignant migrating partial seizures of infancy, seizures, benign familial neonatal, 1, benign familial neonatal-infantile seizures, benign neonatal seizures, seizures, benign familial neonatal, 2, undetermined early-onset epileptic encephalopathy, neonatal-onset developmental and epileptic encephalopathy.

BP4

Computational evidence support a benign effect (MetaRNN=0.41681403).

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.0000985 (15/152224) while in subpopulation AMR AF = 0.000262 (4/15292). AF 95% confidence interval is 0.0000887. There are 0 homozygotes in GnomAd4. There are 5 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High AC in GnomAd4 at 15 AD gene.

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

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KCNQ2	NM_172107.4	MANE Select	c.2252C>T	p.Ser751Leu	missense	Exon 17 of 17	NP_742105.1	O43526-1
KCNQ2	NM_001382235.1		c.2306C>T	p.Ser769Leu	missense	Exon 17 of 17	NP_001369164.1	A0A9L9PXL0
KCNQ2	NM_172106.3		c.2198C>T	p.Ser733Leu	missense	Exon 16 of 16	NP_742104.1	O43526-2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KCNQ2	ENST00000359125.7	TSL:1 MANE Select	c.2252C>T	p.Ser751Leu	missense	Exon 17 of 17	ENSP00000352035.2	O43526-1
KCNQ2	ENST00000626839.2	TSL:1	c.2198C>T	p.Ser733Leu	missense	Exon 16 of 16	ENSP00000486706.1	O43526-2
KCNQ2	ENST00000344462.8	TSL:1	c.2159C>T	p.Ser720Leu	missense	Exon 16 of 16	ENSP00000339611.4	O43526-4

Frequencies

GnomAD3 genomes

AF:

0.0000985

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

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:

0.000118

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000652

AC:

AN:

138110

AF XY:

0.0000656

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000368

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

AF:

0.0000949

AC:

131

AN:

1380930

Hom.:

Cov.:

AF XY:

0.0000985

AC XY:

AN XY:

680422

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31598

American (AMR)

AF:

0.000308

AC:

AN:

35686

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24576

East Asian (EAS)

AF:

0.00

AC:

AN:

36182

South Asian (SAS)

AF:

0.00

AC:

AN:

79278

European-Finnish (FIN)

AF:

0.00

AC:

AN:

36012

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5418

European-Non Finnish (NFE)

AF:

0.000107

AC:

115

AN:

1074746

Other (OTH)

AF:

0.0000871

AC:

AN:

57434

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000985

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74358

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41470

American (AMR)

AF:

0.000262

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4838

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000118

AC:

AN:

68016

Other (OTH)

AF:

0.000478

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000982

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Developmental and epileptic encephalopathy, 7 (1)

Early-infantile DEE (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.17

BayesDel_addAF

Uncertain

0.040

BayesDel_noAF

Uncertain

0.13

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.041

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.25

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.56

MetaRNN

Benign

0.42

MetaSVM

Pathogenic

0.93

MutationAssessor

Uncertain

2.0

PhyloP100

9.3

PrimateAI

Uncertain

0.74

PROVEAN

Benign

-1.9

REVEL

Uncertain

0.55

Sift

Benign

0.26

Sift4G

Benign

0.28

Varity_R

0.17

gMVP

0.41

Mutation Taster

=79/21

polymorphism

(source)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over