7-150952757-C-T

Variant names:

• chr7-150952757-C-T
• rs539146547
• NM_000238.4:c.1225G>A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM1 PP3 BS2

The NM_000238.4(KCNH2):​c.1225G>A​(p.Val409Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,614,144 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 Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000027 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 7.76

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]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM1: In a transmembrane_region Helical; Name=Segment S1 (size 20) in uniprot entity KCNH2_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000238.4
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.777
• BS2: High AC in GnomAdExome4 at 40 AD,Digenic gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1225G>A	p.Val409Met	missense_variant	Exon 6 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1225G>A	p.Val409Met	missense_variant	Exon 6 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152146 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000636 AC: 16 AN: 251470 Hom.: 0 AF XY: 0.0000589 AC XY: 8 AN XY: 135910

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000318

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000274 AC: 40 AN: 1461880 Hom.: 0 Cov.: 34 AF XY: 0.0000303 AC XY: 22 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000291

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000171

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152264 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74456

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000277 Hom.: 0

Bravo AF: 0.0000302

ExAC AF: 0.0000659 AC: 8

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Uncertain:2

Sep 27, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces valine with methionine at codon 409 of the KCNH2 protein. Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. This variant is found within a highly conserved pore region (a.a. 404-659). Rare non-truncating variants in this region have been shown to be significantly overrepresented in individuals with long QT syndrome (PMID: 32893267). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with epilepsy (PMID: 31696929) and in an individual affected with sudden infant death (PMID: 37589201). This variant has been identified in 16/251470 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 409 of the KCNH2 protein (p.Val409Met). This variant is present in population databases (rs539146547, gnomAD 0.03%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with KCNH2-related conditions (PMID: 31696929, 32233023, 37589201). ClinVar contains an entry for this variant (Variation ID: 456884). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Long QT syndrome 2 Uncertain:1

Jun 24, 2022

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as VUS-3B. Following criteria are met: 0103 - Dominant negative and loss of function are known mechanisms of disease in this gene and are associated with long QT syndrome 2 (MIM#613688). Gain of function is also a known mechanism associated with short QT syndrome 1 (MIM#609620) (OMIM, PMID: 10753933; PMID: 21777565). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0112 - The condition associated with this gene has incomplete penetrance (PMID: 20301308). (I) 0200 - Variant is predicted to result in a missense amino acid change from valine to methionine. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (16 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (1 heterozygote, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0601 - Variant is located in the well-established functional S1 transmembrane domain. The S1 transmembrane domain has been shown to play a role in regulating channel activation and deactivation (PMID: 28280240). (SP) 0710 - Other missense variants comparable to the one identified in this case have inconclusive previous evidence for pathogenicity. Alternative missense changes to glutamic acid and leucine have been described as variants of unknown significance in ClinVar and the literature, respectively (PMID: 32383558). (I) 0809 - Previous evidence of pathogenicity for this variant is inconclusive. This variant is present in ClinVar as a VUS. It has also been reported as a VUS in the literature in a patient with epilepsy and in a patient with Wolff-Parkinson-White syndrome (PMID: 31696929, 32233023). (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Wolff-Parkinson-White pattern Uncertain:1

Jul 14, 2017

Lupski Lab, Baylor-Hopkins CMG, Baylor College of Medicine

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: research

This variant was identified in an individual with Wolff-Parkinson-White syndrome -

not provided Uncertain:1

Feb 08, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Identified in association with epilepsy, sudden infant death syndrome (SIDS), and Wolff-Parkinson-White (WPW) syndrome (PMID: 31696929, 37589201, 32233023); also reported as p.(V69M) due to alternate nomenclature; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 32233023, 31696929, 37589201) -

Short QT syndrome type 1;C3150943:Long QT syndrome 2 Uncertain:1

Aug 02, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiac arrhythmia Uncertain:1

Jan 03, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces valine with methionine at codon 409 of the KCNH2 protein. Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. This variant is found within a highly conserved pore region (a.a. 404-659). Rare non-truncating variants in this region have been shown to be significantly overrepresented in individuals with long QT syndrome (PMID: 32893267). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with epilepsy (PMID: 31696929) and in an individual affected with sudden infant death (PMID: 37589201). This variant has been identified in 16/251470 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	.;D;D
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Pathogenic	0.61	D
MetaRNN	Pathogenic	0.78	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.4	.;M;.
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-2.8	D;D;.
REVEL	Pathogenic	0.88
Sift	Uncertain	0.0030	D;D;.
Sift4G	Uncertain	0.019	D;D;T
Polyphen		0.88	P;D;.
Vest4		0.86
MutPred		0.44		.;Gain of sheet (P = 0.0477);.;
MVP		0.98
MPC		2.2
ClinPred		0.73	D
GERP RS		4.8
Varity_R		0.54
gMVP		0.85

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs539146547; hg19: chr7-150649845;