chr7-150958059-C-G

Variant names:

• chr7-150958059-C-G
• rs199472884
• NM_000238.4:c.916G>C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_000238.4(KCNH2):​c.916G>C​(p.Gly306Arg) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G306W) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNH2 NM_000238.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 0.251

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 Pathogenic. Variant got 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150958059-C-A is described in Lovd as [Pathogenic].
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 7-150958059-C-G is Pathogenic according to our data. Variant chr7-150958059-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67543.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.916G>C	p.Gly306Arg	missense_variant, splice_region_variant	Exon 4 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.916G>C	p.Gly306Arg	missense_variant, splice_region_variant	Exon 4 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000532957.5	n.1139G>C		splice_region_variant, non_coding_transcript_exon_variant	Exon 4 of 9	2
KCNH2	ENST00000684241.1	n.1749G>C		splice_region_variant, non_coding_transcript_exon_variant	Exon 2 of 13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome 2 Pathogenic:1

Aug 15, 2014

Blueprint Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Long QT syndrome Pathogenic:1

Jun 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 306 of the KCNH2 protein (p.Gly306Arg). This variant also falls at the last nucleotide of exon 4, which is part of the consensus splice site for this exon. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with long QT syndrome (PMID: 18752142; Invitae). ClinVar contains an entry for this variant (Variation ID: 67543). 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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Congenital long QT syndrome Other:1

-

Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

This variant has been reported as associated with Long QT syndrome in the following publications (PMID:18752142). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.60	D;T
Eigen	Benign	0.14
Eigen_PC	Benign	0.17
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.86	D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.76	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.2	M;.
PrimateAI	Pathogenic	0.92	D
PROVEAN	Uncertain	-3.4	D;.
REVEL	Pathogenic	0.82
Sift	Uncertain	0.011	D;.
Sift4G	Uncertain	0.038	D;T
Polyphen		0.78	P;.
Vest4		0.48
MutPred		0.75		Gain of solvent accessibility (P = 0.019);.;
MVP		1.0
MPC		1.7
ClinPred		0.94	D
GERP RS		3.8
Varity_R		0.52
gMVP		0.68

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.83		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.83		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs199472884; hg19: chr7-150655147;