7-150959593-G-C

Position:

• chr7-150959593-G-C

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_Moderate BS2_Supporting

The NM_000238.4(KCNH2):​c.451C>G​(p.Pro151Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000547 in 1,461,794 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P151S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: -0.541

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 -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.10961029).
• BS2: High AC in GnomAdExome4 at 8 AD,Digenic gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNH2	NM_000238.4	c.451C>G	p.Pro151Ala	missense_variant	3/15	ENST00000262186.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNH2	ENST00000262186.10	c.451C>G	p.Pro151Ala	missense_variant	3/15	1	NM_000238.4	P1
KCNH2	ENST00000532957.5	n.674C>G		non_coding_transcript_exon_variant	3/9	2
KCNH2	ENST00000684241.1	n.1284C>G		non_coding_transcript_exon_variant	1/13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461794 Hom.: 0 Cov.: 32 AF XY: 0.00000963 AC XY: 7 AN XY: 727202

Gnomad4 AFR exome AF: 0.00

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: 0.00000719

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Dec 01, 2023	This missense variant replaces proline with alanine at codon 151 of the KCNH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). 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 not been identified 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 30, 2022	This sequence change replaces proline, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 151 of the KCNH2 protein (p.Pro151Ala). 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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The alanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 405361). This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. This variant is not present in population databases (gnomAD no frequency). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 12, 2023

The p.P151A variant (also known as c.451C>G), located in coding exon 3 of the KCNH2 gene, results from a C to G substitution at nucleotide position 451. The proline at codon 151 is replaced by alanine, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. 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

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Aug 02, 2021

- -

Cardiac arrhythmia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Jun 09, 2023

This missense variant replaces proline with alanine at codon 151 of the KCNH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). 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 not been identified 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	0.052
BayesDel_addAF	Uncertain	0.015	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	14
DANN	Benign	0.73
DEOGEN2	Benign	0.32	T
Eigen	Benign	-0.82
Eigen_PC	Benign	-0.69
FATHMM_MKL	Benign	0.27	N
LIST_S2	Benign	0.61	T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.11	T
MetaSVM	Uncertain	0.27	D
MutationAssessor	Benign	1.6	L
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-0.69	N
REVEL	Uncertain	0.34
Sift	Benign	0.16	T
Sift4G	Benign	0.56	T
Polyphen		0.0	B
Vest4		0.32
MutPred		0.25		Loss of glycosylation at P151 (P = 0.0131);
MVP		0.59
MPC		0.98
ClinPred		0.43	T
GERP RS		1.6
Varity_R		0.037
gMVP		0.30

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: rs1060500674; hg19: chr7-150656681;