chr7-150951097-C-T

Variant names:

• chr7-150951097-C-T
• rs199472978
• NM_000238.4:c.1969G>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PS3 PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_000238.4(KCNH2):​c.1969G>A​(p.Gly657Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 14/25 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). ClinVar reports functional evidence for this variant: "SCV001736711: "In vitro functional studies have demonstrated an impact to normal KCNH2 potassium channel function, including when the variant is co-expressed with wild-type." Perry 2016, Hardman 2007); SCV000261846: Experimental studies have shown that this missense change affects KCNH2 function (PMID:17823114, 19841300, 25348405, 26958806).; SCV005325354: Published functional studies demonstrate a damaging effect, including defective protein expression, reduced charge during repolarization, reduced IKv11.1 amplitude in response to premature depolarization, and slower deactivation kinetics (Perry et al., 2016)". Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G657C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:1 O:1
• Conservation: PhyloP100: 7.86
• Publications: 11 publications found

Genes affected

KCNH2 (HGNC:6251): (potassium voltage-gated channel subfamily H member 2) This gene encodes a component of a voltage-activated potassium channel found in cardiac muscle, nerve cells, and microglia. Four copies of this protein interact with one copy of the KCNE2 protein to form a functional potassium channel. Mutations in this gene can cause long QT syndrome type 2 (LQT2). Transcript variants encoding distinct isoforms have been identified. [provided by RefSeq, May 2022]

KCNH2 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• short QT syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• short QT syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• Brugada syndrome

  Inheritance: AD Classification: MODERATE, NO_KNOWN Submitted by: ClinGen, Genomics England PanelApp

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV001736711: "In vitro functional studies have demonstrated an impact to normal KCNH2 potassium channel function, including when the variant is co-expressed with wild-type." Perry 2016, Hardman 2007); SCV000261846: Experimental studies have shown that this missense change affects KCNH2 function (PMID: 17823114, 19841300, 25348405, 26958806).; SCV005325354: Published functional studies demonstrate a damaging effect, including defective protein expression, reduced charge during repolarization, reduced IKv11.1 amplitude in response to premature depolarization, and slower deactivation kinetics (Perry et al., 2016)
• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 18 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150951097-CG-AA is described in ClinVar as Pathogenic. ClinVar VariationId is 943187.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 158 curated pathogenic missense variants (we use a threshold of 10). The gene has 38 curated benign missense variants. Gene score misZ: 3.3724 (above the threshold of 3.09). Trascript score misZ: 2.4846 (below the threshold of 3.09). GenCC associations: The gene is linked to long QT syndrome 2, short QT syndrome type 1, short QT syndrome, Brugada syndrome, long QT syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.953
• PP5: Variant 7-150951097-C-T is Pathogenic according to our data. Variant chr7-150951097-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 67348.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000238.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	NM_000238.4	MANE Select	c.1969G>A	p.Gly657Ser	missense	Exon 8 of 15	NP_000229.1	A0A090N8Q0
	KCNH2	NM_001406753.1		c.1681G>A	p.Gly561Ser	missense	Exon 6 of 13	NP_001393682.1	Q12809-7
	KCNH2	NM_172056.3		c.1969G>A	p.Gly657Ser	missense	Exon 8 of 9	NP_742053.1	Q12809-5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	ENST00000262186.10	TSL:1 MANE Select	c.1969G>A	p.Gly657Ser	missense	Exon 8 of 15	ENSP00000262186.5	Q12809-1
	KCNH2	ENST00000330883.9	TSL:1	c.949G>A	p.Gly317Ser	missense	Exon 4 of 11	ENSP00000328531.4	Q12809-2
	KCNH2	ENST00000461280.2	TSL:1	n.1267G>A		non_coding_transcript_exon	Exon 4 of 5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

Alfa AF: 0.000179 Hom.: 0

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Cardiovascular phenotype (1)
1	-	-	Congenital long QT syndrome (2)
1	-	-	Long QT syndrome (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	H
PhyloP100		7.9
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.8	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.98
MVP		1.0
MPC		2.2
ClinPred		1.0	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		3.2
Varity_R		0.92
gMVP		0.98
Mutation Taster		=8/92	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.45		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.45		Position offset: -2

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

Other links and lift over

dbSNP: rs199472978; hg19: chr7-150648185; COSMIC: COSV51130527;