chr7-150947431-C-A

Variant names:

• chr7-150947431-C-A
• rs950543448
• NM_000238.4:c.3049G>T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_000238.4(KCNH2):​c.3049G>T​(p.Ala1017Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000484 in 1,444,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000031 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:6
• Conservation: PhyloP100: -0.196

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 -2 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.11937195).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.3049G>T	p.Ala1017Ser	missense_variant	Exon 13 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.3049G>T	p.Ala1017Ser	missense_variant	Exon 13 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000330883.9	c.2029G>T	p.Ala677Ser	missense_variant	Exon 9 of 11	1		ENSP00000328531.4
KCNH2	ENST00000684241.1	n.3882G>T		non_coding_transcript_exon_variant	Exon 11 of 13

Frequencies

GnomAD3 genomes AF: 0.0000199 AC: 3 AN: 150784 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000486

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000148

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000640 AC: 1 AN: 156338 Hom.: 0 AF XY: 0.0000118 AC XY: 1 AN XY: 84610

Gnomad AFR exome AF: 0.000130

Gnomad AMR exome AF: 0.00

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000309 AC: 4 AN: 1294098 Hom.: 0 Cov.: 35 AF XY: 0.00000467 AC XY: 3 AN XY: 642110

Gnomad4 AFR exome AF: 0.0000334

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: 0.00000304

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000199 AC: 3 AN: 150784 Hom.: 0 Cov.: 33 AF XY: 0.0000407 AC XY: 3 AN XY: 73682

Gnomad4 AFR AF: 0.0000486

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000148

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000227

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Uncertain:2

Jul 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1017 of the KCNH2 protein (p.Ala1017Ser). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. ClinVar contains an entry for this variant (Variation ID: 565852). 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 tolerated. 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. -

Oct 06, 2023

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 alanine with serine at codon 1017 of the KCNH2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). This variant is found within a highly conserved C-terminus region (a.a. 843-1159). 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 not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 1/156338 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. -

not provided Uncertain:1

Dec 08, 2021

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Has not been previously published as pathogenic or benign to our knowledge; Not observed at significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant does not alter protein structure/function -

Cardiovascular phenotype Uncertain:1

May 22, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A1017S variant (also known as c.3049G>T), located in coding exon 13 of the KCNH2 gene, results from a G to T substitution at nucleotide position 3049. The alanine at codon 1017 is replaced by serine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Nov 14, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiac arrhythmia Uncertain:1

Oct 01, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with serine at codon 1017 of the KCNH2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). This variant is found within a highly conserved C-terminus region (a.a. 843-1159). 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 not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 1/156338 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	0.073
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	19
DANN	Benign	0.89
DEOGEN2	Benign	0.31	.;T
Eigen	Benign	-0.81
Eigen_PC	Benign	-0.67
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.83	T;T
M_CAP	Pathogenic	0.46	D
MetaRNN	Benign	0.12	T;T
MetaSVM	Uncertain	0.20	D
MutationAssessor	Benign	-0.20	.;N
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	0.26	N;N
REVEL	Uncertain	0.59
Sift	Benign	0.72	T;T
Sift4G	Benign	0.79	T;T
Polyphen		0.034	B;B
Vest4		0.15
MVP		0.90
MPC		0.16
ClinPred		0.034	T
GERP RS		2.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.4
Varity_R		0.087
gMVP		0.54

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs950543448; hg19: chr7-150644519;