7-150959598-C-T

Position:

• chr7-150959598-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000238.4(KCNH2):​c.446G>A​(p.Gly149Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -0.0410

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.23598146).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.446G>A	p.Gly149Asp	missense_variant	3/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.446G>A	p.Gly149Asp	missense_variant	3/15	1	NM_000238.4	ENSP00000262186	P1
KCNH2	ENST00000532957.5	n.669G>A		non_coding_transcript_exon_variant	3/9	2
KCNH2	ENST00000684241.1	n.1279G>A		non_coding_transcript_exon_variant	1/13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 09, 2022

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 863779). 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). This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 149 of the KCNH2 protein (p.Gly149Asp). -

Cardiac arrhythmia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Feb 02, 2022

This missense variant replaces glycine with aspartic acid at codon 149 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	0.16
BayesDel_addAF	Uncertain	0.034	T
BayesDel_noAF	Benign	-0.19
CADD	Benign	17
DANN	Benign	0.96
DEOGEN2	Benign	0.34	T
Eigen	Benign	-0.64
Eigen_PC	Benign	-0.50
FATHMM_MKL	Benign	0.12	N
LIST_S2	Benign	0.76	T
M_CAP	Uncertain	0.26	D
MetaRNN	Benign	0.24	T
MetaSVM	Uncertain	0.46	D
MutationAssessor	Benign	1.6	L
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-0.86	N
REVEL	Uncertain	0.38
Sift	Benign	0.65	T
Sift4G	Benign	0.65	T
Polyphen		0.020	B
Vest4		0.36
MutPred		0.37		Loss of MoRF binding (P = 0.0837);
MVP		0.49
MPC		1.3
ClinPred		0.16	T
GERP RS		3.8
Varity_R		0.087
gMVP		0.59

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: rs199472865; hg19: chr7-150656686;