rs199472894

Variant names:

• chr7-150952720-G-A
• rs199472894
• NM_000238.4:c.1262C>T

Your query was ambiguous. Multiple possible variants found:

• chr7-150952720-G-A
• chr7-150952720-G-C
• chr7-150952720-G-T

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.1262C>T​(p.Thr421Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,886 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 14/23 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: "SCV000234088: Published functional studies demonstrate a damaging effect: decreased ability to restore normal repolarization in KCNH2-knockdown embryonic zebrafish in vivo and reduced potassium current due to abnormal protein trafficking and altered channel gating in vitro (PMID:23303164, 23136156)" and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T421R) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:2 O:1
• Conservation: PhyloP100: 9.81
• Publications: 18 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: SCV000234088: Published functional studies demonstrate a damaging effect: decreased ability to restore normal repolarization in KCNH2-knockdown embryonic zebrafish in vivo and reduced potassium current due to abnormal protein trafficking and altered channel gating in vitro (PMID: 23303164, 23136156); SCV005426247: "In-vitro rat myocyte studies demonstrated that when co-expressed with wildtype, this variant causes a dominant negative effect by reducing the potassium current due to abnormal protein trafficking and altered channel gating (PMID: 23136156). In-vivo functional studies using kcnh2-knockdown embryonic zebrafish revealed reduced (5.8%) restoration of normal repolarization (PMID: 23303164)."; SCV006061208: Functional studies have shown that this variant causes a reduction in the membrane expression of KCNH2 protein due to trafficking deficiency and results in reduced potassium channel current and abnormal channel gating (PMID: 23136156, 23303164, 26958806, 28280240).
• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 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 chr7-150952720-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 200331.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, 0.957
• PP5: Variant 7-150952720-G-A is Pathogenic according to our data. Variant chr7-150952720-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 67173.

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.1262C>T	p.Thr421Met	missense	Exon 6 of 15	NP_000229.1	A0A090N8Q0
	KCNH2	NM_001406753.1		c.974C>T	p.Thr325Met	missense	Exon 4 of 13	NP_001393682.1	Q12809-7
	KCNH2	NM_172056.3		c.1262C>T	p.Thr421Met	missense	Exon 6 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.1262C>T	p.Thr421Met	missense	Exon 6 of 15	ENSP00000262186.5	Q12809-1
	KCNH2	ENST00000330883.9	TSL:1	c.242C>T	p.Thr81Met	missense	Exon 2 of 11	ENSP00000328531.4	Q12809-2
	KCNH2	ENST00000461280.2	TSL:1	n.560C>T		non_coding_transcript_exon	Exon 2 of 5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00 AC: 0 AN: 251484 AF XY: 0.00

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: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461886 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 727248

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: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1112008

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
1	1	-	Long QT syndrome (2)
1	-	-	Cardiac arrhythmia (1)
1	-	-	not provided (1)
-	1	-	not specified (1)
-	-	-	Congenital long QT syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
CardioboostArm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.97	D
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.75	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.4	M
PhyloP100		9.8
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.7	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.82		Gain of helix (P = 0.0325)
MVP		1.0
MPC		2.2
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.85
gMVP		0.93
Mutation Taster		=1/99	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs199472894; hg19: chr7-150649808;