KCNQ1 p.Leu266Arg

Variant names:

• chr11-2572862-T-G
• rs199473460
• NM_000218.3:c.797T>G
• KCNQ1 p.Leu266Arg

Your query was ambiguous. Multiple possible variants found:

• chr11-2572862-T-G
• chr11-2572861-CT-AG
• chr11-2572862-TG-GA
• chr11-2572862-TG-GC
• chr11-2572862-TG-GT
• chr11-2572861-CTG-AGA

GermlineCancer (beta)

Variant summary

Our verdict is Likely pathogenic.

+9 Likely Pathogenic

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 9 classification points (ACMG Germline Pathogenicity v2019). PM1PM2PM5PP3_ModeratePP5

The NM_000218.3(KCNQ1):c.797T>G (p.Leu266Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. In-silico predictor (REVEL) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (no review stars). A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.L266Q: Likely_pathogenic (ClinVar VariationId 2498480, 1 star)

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNQ1 NM_000218.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 3.78
• Publications: 26 publications found

Genes affected

KCNQ1 (HGNC:6294): (potassium voltage-gated channel subfamily Q member 1) This gene encodes a voltage-gated potassium channel required for repolarization phase of the cardiac action potential. This protein can form heteromultimers with two other potassium channel proteins, KCNE1 and KCNE3. Mutations in this gene are associated with hereditary long QT syndrome 1 (also known as Romano-Ward syndrome), Jervell and Lange-Nielsen syndrome, and familial atrial fibrillation. This gene exhibits tissue-specific imprinting, with preferential expression from the maternal allele in some tissues, and biallelic expression in others. This gene is located in a region of chromosome 11 amongst other imprinted genes that are associated with Beckwith-Wiedemann syndrome (BWS), and itself has been shown to be disrupted by chromosomal rearrangements in patients with BWS. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Aug 2011]

KCNQ1 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• Jervell and Lange-Nielsen syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Jervell and Lange-Nielsen syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• long QT syndrome 1

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• atrial fibrillation, familial, 3

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• short QT syndrome

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet
• short QT syndrome type 2

  Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• familial atrial fibrillation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Jervell and Lange-Nielsen syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• familial hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: G2P
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

Classification according to ACMG Germline Pathogenicity v2019

Specifications for KCNQ1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Classification was made for transcript:

Our verdict: Likely_pathogenic. The variant received 9 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	PM1Mutational hot spot or critical domain		Missense neighbourhood hotspot (≥2 P/LP within ±8 AA, OR ≥ 5 vs. background) — PM1; In-domain: 0 pathogenic, 0 benign rare missense variants.; ±8 AA neighbourhood: 27 pathogenic, 1 benign (OR vs. background: 91.7).
	PM2Absent/extremely low in population databases		Absent from gnomAD (AD/XL gene) — PM2; Absent from gnomAD at well-covered site (MOI: AD+AR) (base 0.0001, raised to 0.00022 by highest known P/LP ClinVar AF 0.00022) — PM2 moderate.
	PM5Novel missense at known pathogenic residue		Different pathogenic missense at same AA residue in ClinVar (PM5); ClinVar contains a germline Pathogenic/Likely Pathogenic entry at the same amino acid position with a different amino acid change: p.L266Q: Likely_pathogenic (ClinVar VariationId 2498480, 1 star)
	PP3Computational evidence supports damaging effect		Germline meta computational scorer (REVEL/MetaRNN/BayesDel) predicts damaging effect — moderate evidence (PP3); Splicing verdict: not pathogenic.; Germline computational verdict: pathogenic (Moderate).
	PP5Reputable source reports pathogenic		ClinVar 0-star pathogenic — supporting (PP5); ClinVar germline classification: Pathogenic/Likely Pathogenic, 0 star(s).

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_000218.3. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KCNQ1 NM_000218.3	MANE Select	c.797T>G p.Leu266Arg	missense	Exon 6 of 16	Prot: NP_000209.2
	KCNQ1 NM_001406836.1		c.797T>G p.Leu266Arg	missense	Exon 6 of 15	Prot: NP_001393765.1
	KCNQ1 NM_001406837.1		c.527T>G p.Leu176Arg	missense	Exon 7 of 17	Prot: NP_001393766.1

KCNQ1 NM_000218.3

MANE Select

HGVSc / HGVSpc.797T>Gp.Leu266Arg

Exon rankExon 6 of 16

missense

Prot: NP_000209.2

KCNQ1 NM_001406836.1

HGVSc / HGVSpc.797T>Gp.Leu266Arg

Exon rankExon 6 of 15

missense

Prot: NP_001393765.1

KCNQ1 NM_001406837.1

HGVSc / HGVSpc.527T>Gp.Leu176Arg

Exon rankExon 7 of 17

missense

Prot: NP_001393766.1

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KCNQ1 ENST00000155840.12	TSL:1MANE Select	c.797T>G p.Leu266Arg	missense	Exon 6 of 16	Prot: ENSP00000155840.2 UniProt:
	KCNQ1 ENST00000335475.6	TSL:1	c.416T>G p.Leu139Arg	missense	Exon 6 of 16	Prot: ENSP00000334497.5 UniProt:
	KCNQ1 ENST00000910997.1		c.794T>G p.Leu265Arg	missense	Exon 6 of 16	Prot: ENSP00000581056.1 UniProt:

KCNQ1 ENST00000155840.12

TSL:1MANE Select

HGVSc / HGVSpc.797T>Gp.Leu266Arg

Exon rankExon 6 of 16

missense

Prot: ENSP00000155840.2UniProt: P51787-1

KCNQ1 ENST00000335475.6

TSL:1

HGVSc / HGVSpc.416T>Gp.Leu139Arg

Exon rankExon 6 of 16

missense

Prot: ENSP00000334497.5UniProt: P51787-2

KCNQ1 ENST00000910997.1

HGVSc / HGVSpc.794T>Gp.Leu265Arg

Exon rankExon 6 of 16

missense

Prot: ENSP00000581056.1UniProt: A0ACI8SIJ2

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 3 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:33
GnomAD4 exome	AF:	AC:	Hom:	AN:	Cov:32
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:33

Showing 3 sources

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Cardiovascular phenotype (1)
1	-	-	Long QT syndrome (1)
1	-	-	not provided (1)

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
AlphaGenome AVI	Pathogenic	26
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	29
CardioboostArm	Pathogenic	1.0
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Uncertain	0.95	D
FuncVEP CTI	Pathogenic	0.99
GPN-Star LLR	N/A	-9.8
GPN-Star score	N/A	9.8
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
Mutation Taster	N/A	8/92	disease causing (ClinVar)
MutationAssessor	Pathogenic	3.1	M
PhyloP100	Uncertain	3.8
popEVE	Benign	-4.5
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.8	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.0080	D
Varity_R	N/A	0.99
VESM-3B	Benign	-17

Showing 29 of 29 scores

Splicing Scores

Algorithm	Calibrated pred.	Score	Prediction
Pangolin (max)	Benign	0.010
SpliceAI score (max)	Benign	0.010	Details are displayed if max score is > 0.2

Showing 2 of 2 scores

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.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

No MaveDB functional evidence found for this variant.

Other links and lift over

dbSNP: rs199473460;

hg19: chr11-2594092;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar