7-150974897-C-T

Variant names:

• chr7-150974897-C-T
• rs199472835
• NM_000238.4:c.121G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 7P and 1B. PM1 PM2 PM5 PP2 BP4

The NM_000238.4(KCNH2):​c.121G>A​(p.Val41Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,776 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/23 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V41A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.45
• Publications: 0 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 20 uncertain in NM_000238.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-150974897-C-G is described in CliVar as Likely_pathogenic. Clinvar id is 372589.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.41019273).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH2	NM_000238.4	c.121G>A	p.Val41Ile	missense_variant	Exon 2 of 15	ENST00000262186.10	NP_000229.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH2	ENST00000262186.10	c.121G>A	p.Val41Ile	missense_variant	Exon 2 of 15	1	NM_000238.4	ENSP00000262186.5
KCNH2	ENST00000713710.1	c.121G>A	p.Val41Ile	missense_variant	Exon 2 of 15			ENSP00000519013.1
KCNH2	ENST00000532957.5	n.344G>A		non_coding_transcript_exon_variant	Exon 2 of 9	2
KCNH2	ENST00000713700.1	n.79G>A		non_coding_transcript_exon_variant	Exon 2 of 9

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458776 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 725648

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33384

American (AMR) AF: 0.00 AC: 0 AN: 44548

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26072

East Asian (EAS) AF: 0.00 AC: 0 AN: 39614

South Asian (SAS) AF: 0.00 AC: 0 AN: 86050

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51994

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111104

Other (OTH) AF: 0.00 AC: 0 AN: 60266

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.084
CardioboostArm	Benign	0.000014
BayesDel_addAF	Uncertain	0.055	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	23
DANN	Benign	0.97
DEOGEN2	Uncertain	0.59	D
Eigen	Benign	-0.76
Eigen_PC	Benign	-0.46
FATHMM_MKL	Benign	0.61	D
LIST_S2	Uncertain	0.89	D
M_CAP	Pathogenic	0.66	D
MetaRNN	Benign	0.41	T
MetaSVM	Uncertain	0.46	D
MutationAssessor	Benign	-2.5	N
PhyloP100		1.4
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	0.43	N
REVEL	Uncertain	0.41
Sift	Benign	1.0	T
Sift4G	Benign	1.0	T
Polyphen		0.0	B
Vest4		0.34
MutPred		0.74		Loss of catalytic residue at V41 (P = 0.0527);
MVP		0.48
MPC		0.83
ClinPred		0.24	T
GERP RS		4.1
Varity_R		0.23
gMVP		0.77
Mutation Taster		=47/53	disease causing

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

Other links and lift over

dbSNP: rs199472835; hg19: chr7-150671985;