rs796052675

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PVS1PP5

The NM_004519.4(KCNQ3):​c.679C>T​(p.Arg227*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,038 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R227R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

KCNQ3
NM_004519.4 stop_gained

Scores

2
4

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 1.12

Publications

1 publications found
Variant links:
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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PP5
Variant 8-132180255-G-A is Pathogenic according to our data. Variant chr8-132180255-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 205961.

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.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
KCNQ3
NM_004519.4
MANE Select
c.679C>Tp.Arg227*
stop_gained
Exon 4 of 15NP_004510.1O43525-1
KCNQ3
NM_001204824.2
c.319C>Tp.Arg107*
stop_gained
Exon 4 of 15NP_001191753.1O43525-2

Ensembl Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
KCNQ3
ENST00000388996.10
TSL:1 MANE Select
c.679C>Tp.Arg227*
stop_gained
Exon 4 of 15ENSP00000373648.3O43525-1
KCNQ3
ENST00000519445.5
TSL:5
c.679C>Tp.Arg227*
stop_gained
Exon 4 of 15ENSP00000428790.1E7ET42
KCNQ3
ENST00000521134.6
TSL:2
c.319C>Tp.Arg107*
stop_gained
Exon 4 of 15ENSP00000429799.1O43525-2

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251132
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.0000463
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000342
AC:
5
AN:
1461802
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
727194
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.0000187
AC:
1
AN:
53340
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.00000270
AC:
3
AN:
1112002
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.495
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
AF XY:
0.0000134
AC XY:
1
AN XY:
74386
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41460
American (AMR)
AF:
0.00
AC:
0
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68048
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.325
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00
Hom.:
0
Bravo
AF:
0.00000756

ClinVar

ClinVar submissions
Significance:Conflicting classifications of pathogenicity
Revision:criteria provided, conflicting classifications
View on ClinVar
Pathogenic
VUS
Benign
Condition
1
-
-
Benign neonatal seizures (1)
-
1
-
not provided (1)
1
-
-
Seizures, benign familial neonatal, 2 (1)

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Pathogenic
0.56
CADD
Pathogenic
40
DANN
Uncertain
1.0
Eigen
Uncertain
0.52
Eigen_PC
Uncertain
0.35
FATHMM_MKL
Uncertain
0.83
D
PhyloP100
1.1
Vest4
0.98
GERP RS
2.6
Mutation Taster
=0/200
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs796052675; hg19: chr8-133192502; COSMIC: COSV66479891; API