NM_000238.4:c.2230C>G

Variant names:

• chr7-150950336-G-C
• rs189014161
• NM_000238.4:c.2230C>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_000238.4(KCNH2):​c.2230C>G​(p.Arg744Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,613,482 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R744Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 30)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.20
• Publications: 15 publications found

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]

KCNH2 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• short QT syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• short QT syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• Brugada syndrome

  Inheritance: AD Classification: MODERATE, NO_KNOWN Submitted by: ClinGen, Genomics England PanelApp

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 158 curated pathogenic missense variants (we use a threshold of 10). The gene has 38 curated benign missense variants. Gene score misZ: 3.3724 (above the threshold of 3.09). Trascript score misZ: 2.4846 (below the threshold of 3.09). GenCC associations: The gene is linked to long QT syndrome 2, Brugada syndrome, short QT syndrome type 1, short QT syndrome, long QT syndrome.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000238.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	NM_000238.4	MANE Select	c.2230C>G	p.Arg744Gly	missense	Exon 9 of 15	NP_000229.1
	KCNH2	NM_001406753.1		c.1942C>G	p.Arg648Gly	missense	Exon 7 of 13	NP_001393682.1
	KCNH2	NM_172056.3		c.2230C>G	p.Arg744Gly	missense	Exon 9 of 9	NP_742053.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	ENST00000262186.10	TSL:1 MANE Select	c.2230C>G	p.Arg744Gly	missense	Exon 9 of 15	ENSP00000262186.5
	KCNH2	ENST00000330883.9	TSL:1	c.1210C>G	p.Arg404Gly	missense	Exon 5 of 11	ENSP00000328531.4
	KCNH2	ENST00000461280.2	TSL:1	n.1528C>G		non_coding_transcript_exon	Exon 5 of 5

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152146 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000160 AC: 4 AN: 249862 AF XY: 0.0000295

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000888

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461218 Hom.: 0 Cov.: 38 AF XY: 0.00000138 AC XY: 1 AN XY: 726942

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52862

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111924

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152264 Hom.: 0 Cov.: 30 AF XY: 0.0000269 AC XY: 2 AN XY: 74446

African (AFR) AF: 0.00 AC: 0 AN: 41556

American (AMR) AF: 0.000131 AC: 2 AN: 15302

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5174

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68004

Other (OTH) AF: 0.00 AC: 0 AN: 2112

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Uncertain:1

Dec 14, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: 1515578). This variant has not been reported in the literature in individuals affected with KCNH2-related conditions. This variant is present in population databases (rs189014161, gnomAD 0.006%). This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 744 of the KCNH2 protein (p.Arg744Gly). This variant disrupts the p.Arg744 amino acid residue in KCNH2. Other variant(s) that disrupt this residue have been observed in individuals with KCNH2-related conditions (PMID: 22314138, 26746457), which suggests that this may be a clinically significant amino acid residue. 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
CardioboostArm	Uncertain	0.83
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Pathogenic	0.19
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.59	D
MetaRNN	Uncertain	0.54	D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Benign	1.4	L
PhyloP100		1.2
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-4.8	D
REVEL	Pathogenic	0.68
Sift	Uncertain	0.0050	D
Sift4G	Benign	0.083	T
Polyphen		0.77	P
Vest4		0.61
MVP		0.98
MPC		1.7
ClinPred		0.89	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.9
Varity_R		0.43
gMVP		0.79
Mutation Taster		=59/41	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs189014161; hg19: chr7-150647424;