rs199472986

Positions:

• chr7-150950404-G-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000238.4(KCNH2):​c.2162C>T​(p.Pro721Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 30)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 9.95

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 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.976
• PP5: Variant 7-150950404-G-A is Pathogenic according to our data. Variant chr7-150950404-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 67371.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-150950404-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.2162C>T	p.Pro721Leu	missense_variant	9/15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.2162C>T	p.Pro721Leu	missense_variant	9/15	1	NM_000238.4	ENSP00000262186.5

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 30

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital long QT syndrome Pathogenic:1 Other:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 06, 2019	Variant summary: The variant, KCNH2 c.2162C>T (p.Pro721Leu) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 36208 control chromosomes (gnomAD) and has been reported in the literature in individuals affected with Long-QT syndrome (Giudicessi_2012, Itoh_2016, Kapa_2009). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function and state that the missense change leads to a trafficking deficient protein which cannot be corrected in their in vitro studies (Anderson _2014). One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
not provided, no classification provided	literature only	Cardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust	-	This variant has been reported as associated with Long QT syndrome in the following publications (PMID:15840476;PMID:19841300). This is a literature report, and does not necessarily reflect the clinical interpretation of the Imperial College / Royal Brompton Cardiovascular Genetics laboratory. -

Long QT syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 19, 2018

In summary, this variant is absent from population databases, has been observed in at least one patient with long QT syndrome, and has been shown to have a deleterious functional effect. In the absence of confirmed segregation evidence, at this time this variant has been classified as Likely Pathogenic. Experimental studies have shown that this missense change leads to a trafficking-deficient KCNH2 protein that is unable to be corrected in vitro (PMID: 25417810). This variant is not present in population databases (rs199472986, ExAC no frequency). This variant has been reported in at least one individual affected with long QT syndrome (PMID: 15840476, 19841300, 22949429, 26669661). ClinVar contains an entry for this variant (Variation ID: 67371). This sequence change replaces proline with leucine at codon 721 of the KCNH2 protein (p.Pro721Leu). The proline residue is highly conserved and there is a moderate physicochemical difference between proline and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	.;D;D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	.;H;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-9.4	D;D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0010	D;D;D
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.98
MutPred		0.79		.;Gain of helix (P = 0.0854);.;
MVP		0.99
MPC		2.2
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.79
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs199472986; hg19: chr7-150647492;