rs199473439

Positions:

• chr7-150947806-C-A
• chr7-150947806-C-G
• chr7-150947806-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PM5

The NM_000238.4(KCNH2):​c.2765G>T​(p.Arg922Leu) 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R922W) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.414

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.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150947807-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.2765G>T	p.Arg922Leu	missense_variant	12/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.2765G>T	p.Arg922Leu	missense_variant	12/15	1	NM_000238.4	ENSP00000262186	P1
KCNH2	ENST00000330883.9	c.1745G>T	p.Arg582Leu	missense_variant	8/11	1		ENSP00000328531
KCNH2	ENST00000684241.1	n.3598G>T		non_coding_transcript_exon_variant	10/13

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1378530 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 679520

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiac arrhythmia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Nov 04, 2019

This missense variant replaces arginine with leucine at codon 922 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed 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	0.064
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Benign	17
DANN	Uncertain	0.99
DEOGEN2	Benign	0.36	.;T
Eigen	Benign	-0.35
Eigen_PC	Benign	-0.34
FATHMM_MKL	Benign	0.19	N
LIST_S2	Benign	0.71	T;T
M_CAP	Pathogenic	0.71	D
MetaRNN	Uncertain	0.58	D;D
MetaSVM	Uncertain	0.58	D
MutationAssessor	Benign	1.0	.;L
MutationTaster	Benign	0.58	D;N;N
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.94	N;N
REVEL	Uncertain	0.63
Sift	Benign	0.22	T;T
Sift4G	Benign	0.45	T;T
Polyphen		0.97	D;P
Vest4		0.36
MutPred		0.65		.;Loss of methylation at R922 (P = 0.0098);
MVP		0.97
MPC		0.21
ClinPred		0.19	T
GERP RS		2.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.066
gMVP		0.60

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: rs199473439; hg19: chr7-150644894;