7-150958158-G-A

Variant names:

• chr7-150958158-G-A
• rs552583527
• NM_000238.4:c.817C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000238.4(KCNH2):​c.817C>T​(p.Arg273*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000845 in 1,182,908 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R273R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 8.5e-7 (0 hom.)
• Consequence: KCNH2 NM_000238.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.486
• 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), G2P, Ambry Genetics
• short QT syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• 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: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-150958158-G-A is Pathogenic according to our data. Variant chr7-150958158-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1076382.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	NM_000238.4	MANE Select	c.817C>T	p.Arg273*	stop_gained	Exon 4 of 15	NP_000229.1	A0A090N8Q0
	KCNH2	NM_001406753.1		c.529C>T	p.Arg177*	stop_gained	Exon 2 of 13	NP_001393682.1	Q12809-7
	KCNH2	NM_172056.3		c.817C>T	p.Arg273*	stop_gained	Exon 4 of 9	NP_742053.1	Q12809-5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNH2	ENST00000262186.10	TSL:1 MANE Select	c.817C>T	p.Arg273*	stop_gained	Exon 4 of 15	ENSP00000262186.5	Q12809-1
	KCNH2	ENST00000713710.1		c.817C>T	p.Arg273*	stop_gained	Exon 4 of 15	ENSP00000519013.1	A0AAQ5BGR0
	KCNH2	ENST00000713701.1		c.517C>T	p.Arg173*	stop_gained	Exon 3 of 14	ENSP00000519004.1	A0AAQ5BGQ9

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 8.45e-7 AC: 1 AN: 1182908 Hom.: 0 Cov.: 32 AF XY: 0.00000175 AC XY: 1 AN XY: 572036

⚠️ 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: 23768

American (AMR) AF: 0.00 AC: 0 AN: 12654

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 17726

East Asian (EAS) AF: 0.00 AC: 0 AN: 26416

South Asian (SAS) AF: 0.0000221 AC: 1 AN: 45208

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 28140

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3306

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 977438

Other (OTH) AF: 0.00 AC: 0 AN: 48252

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	Cardiac arrhythmia (1)
1	-	-	Long QT syndrome (1)
1	-	-	Long QT syndrome 2 (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Benign	0.10
Eigen_PC	Benign	-0.13
FATHMM_MKL	Benign	0.40	N
PhyloP100		0.49
Vest4		0.82
GERP RS		1.8
Mutation Taster		=0/200	disease causing (fs/PTC)

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: rs552583527; hg19: chr7-150655246;