NM_000238.4:c.1808G>A

Variant names:

• chr7-150951585-C-T
• rs1554425806
• NM_000238.4:c.1808G>A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000238.4(KCNH2):​c.1808G>A​(p.Gly603Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G603G) has been classified as Benign.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.681

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 4 ACMG points.

• PM1: In a topological_domain Extracellular (size 42) in uniprot entity KCNH2_HUMAN there are 29 pathogenic changes around while only 0 benign (100%) in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.1808G>A	p.Gly603Asp	missense_variant	Exon 7 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.1808G>A	p.Gly603Asp	missense_variant	Exon 7 of 15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Uncertain:1

Sep 06, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 603 of the KCNH2 protein (p.Gly603Asp). This missense change has been observed in individual(s) with long QT syndrome (PMID: 26669661). 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. 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. ClinVar contains an entry for this variant (Variation ID: 456894). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Uncertain	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	.;D;D
Eigen	Benign	-0.25
Eigen_PC	Benign	-0.23
FATHMM_MKL	Benign	0.37	N
LIST_S2	Uncertain	0.89	D;D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Uncertain	0.71	D;D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Benign	1.3	.;L;.
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-2.5	D;D;D
REVEL	Pathogenic	0.88
Sift	Benign	0.15	T;T;T
Sift4G	Uncertain	0.047	D;T;D
Polyphen		0.22	B;B;.
Vest4		0.59
MutPred		0.47		.;Gain of ubiquitination at K608 (P = 0.0605);.;
MVP		0.92
MPC		2.2
ClinPred		0.96	D
GERP RS		4.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.27
gMVP		0.82

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1554425806; hg19: chr7-150648673;