20-63407018-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_172107.4(KCNQ2):c.2245G>C(p.Glu749Gln) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E749K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNQ2 NM_172107.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.68

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KCNQ2
• BP4: Computational evidence support a benign effect (MetaRNN=0.35451737).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.2245G>C	p.Glu749Gln	missense_variant	17/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.2245G>C	p.Glu749Gln	missense_variant	17/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1373628 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 676064

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.42
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
Cadd	Uncertain	24
Dann	Uncertain	1.0
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Pathogenic	0.97	D;D;D;D;D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Benign	0.35	T;T;T;T;T;T
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	0.96	D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.76	T
Sift4G	Benign	0.21	T;.;T;T;T;T
Polyphen		1.0	D;.;D;.;D;D
Vest4		0.27
MutPred		0.21		.;.;Loss of solvent accessibility (P = 0.0431);.;.;.;
MVP		0.65
MPC		1.5
ClinPred		0.89	D
GERP RS		5.2
Varity_R		0.25
gMVP		0.45

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs796052658; hg19: chr20-62038371;