chr7-150951581-GCC-TGA

Variant names:

• chr7-150951581-GCC-TGA
• NM_000238.4:c.1810_1812delGGCinsTCA
• KCNH2 p.Gly604Ser

GermlineCancer (beta)

Variant summary

Our verdict is Uncertain significance.

+4 Uncertain · Hot

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 4 classification points (ACGS-UK Somatic Oncogenicity v2025). O3_ModerateO7_SupportingO8_Supporting

The NM_000238.4(KCNH2):c.1810_1812delGGCinsTCA (p.Gly604Ser) variant causes a missense change. The gene KCNH2 is a known oncogene (CancerMine: 4 oncogene citations). Note: allele frequency estimates from gnomAD may be inaccurate for this variant type (MNP or indel longer than 3 bp) due to technology limitations. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 7.79). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.G604V: Likely_pathogenic (ClinVar VariationId 200741, 1 star) Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.G604D: not_provided (ClinVar VariationId 67282); p.G604= (synonymous): Likely_benign (ClinVar VariationId 926709, 2 stars) This exact variant is curated in the UniProt human variants database as Uncertain Significance.

• Frequency: Genomes: not found (cov: 34)
• Consequence: KCNH2 NM_000238.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.79
• 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: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• 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: Genomics England PanelApp, G2P, ClinGen

Classification according to ACGS-UK Somatic Oncogenicity v2025

Classification was made for transcript:

Our verdict: Uncertain_significance. The variant received 4 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O3Absent or very rare in population		Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = absent, AC = 0 — absent/extremely rare (O3 moderate [+2])
	O7Mutational hotspot or critical domain		Supporting: cancerhotspots.org hit, critical domain, or missense neighbourhood hotspot; No cancerhotspots.org hit at this position; UniProt domain: 0 pathogenic, 0 benign.; ±8 AA neighbourhood: 16 pathogenic, 0 benign (OR vs. background: 165.0); Variant does not impact splicing — splice-hotspot path not applicable
	O8Missense constraint in gene or region		Missense in gene/domain constrained for missense variation where missense is common disease mechanism (O8 supporting); Gene/disease mechanism: missense is a common mechanism of oncogenesis; gnomAD missense Z-score: 2.50 (threshold ≥3.09 for constraint); Domain-level constraint: variant is in a critically constrained functional domain (IS_AT_CRITICAL_DOMAIN)

Variant Effect in Transcripts

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

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KCNH2 NM_000238.4	MANE Select	c.1810_1812delGGCinsTCA p.Gly604Ser	missense	N/A	Prot: NP_000229.1 UniProt:
	KCNH2 NM_001406753.1		c.1522_1524delGGCinsTCA p.Gly508Ser	missense	N/A	Prot: NP_001393682.1 UniProt:
	KCNH2 NM_172056.3		c.1810_1812delGGCinsTCA p.Gly604Ser	missense	N/A	Prot: NP_742053.1 UniProt:

KCNH2 NM_000238.4

MANE Select

HGVSc / HGVSpc.1810_1812delGGCinsTCAp.Gly604Ser

Exon rankN/A

missense

Prot: NP_000229.1UniProt: Q12809-1

KCNH2 NM_001406753.1

HGVSc / HGVSpc.1522_1524delGGCinsTCAp.Gly508Ser

Exon rankN/A

missense

Prot: NP_001393682.1UniProt: Q12809-7

KCNH2 NM_172056.3

HGVSc / HGVSpc.1810_1812delGGCinsTCAp.Gly604Ser

Exon rankN/A

missense

Prot: NP_742053.1UniProt: Q12809-5

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KCNH2 ENST00000262186.10	TSL:1MANE Select	c.1810_1812delGGCinsTCA p.Gly604Ser	missense	N/A	Prot: ENSP00000262186.5 UniProt:
	KCNH2 ENST00000330883.9	TSL:1	c.790_792delGGCinsTCA p.Gly264Ser	missense	N/A	Prot: ENSP00000328531.4 UniProt:
	KCNH2 ENST00000461280.2	TSL:1	n.1108_1110delGGCinsTCA	non_coding_transcript_exon	Exon 3 of 5	Prot:

KCNH2 ENST00000262186.10

TSL:1MANE Select

HGVSc / HGVSpc.1810_1812delGGCinsTCAp.Gly604Ser

Exon rankN/A

missense

Prot: ENSP00000262186.5UniProt: Q12809-1

KCNH2 ENST00000330883.9

TSL:1

HGVSc / HGVSpc.790_792delGGCinsTCAp.Gly264Ser

Exon rankN/A

missense

Prot: ENSP00000328531.4UniProt: Q12809-2

KCNH2 ENST00000461280.2

TSL:1

HGVSc / HGVSpn.1108_1110delGGCinsTCA

Exon rankExon 3 of 5

non_coding_transcript_exon

Prot:

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 2 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:34
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:34

Showing 2 sources

ClinVar

Not reported in ClinVar

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
PhyloP100	Pathogenic	7.8

Showing 1 of 1 scores

Splicing Scores

No splicing scores have been computed for this variant.

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

4 abnormal

4 assays found for this variant.

Clinical calibration: 4 functionally abnormal (PS3), 0 functionally normal (BS3).

Protein level

Scores from arrayed automated patch clamp experiment for KCNH2

Arrayed automated patch clamp experiment for KCNH2

• Gene: KCNH2
• Assay type: Direct protein function
• Mechanism: Monoatomic ion transport and Potassium channel activity
• Model system: Immortalized human cells (Homo sapiens)
• Score: 0.150 · p.Gly604Ser (assay numbering)

Classified as

PS3 moderateFunctionally abnormalInvestigator-provided functional classes: Abnormal function

+2 more calibrations

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: Missense Variants Only: Abnormal function

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: All Variants: Abnormal function

Protein level

Scores from arrayed automated patch clamp experiment for KCNH2

Arrayed automated patch clamp experiment for KCNH2

• Gene: KCNH2
• Assay type: Direct protein function
• Mechanism: Monoatomic ion transport and Potassium channel activity
• Model system: Immortalized human cells (Homo sapiens)
• Score: 0.150 · p.Gly604Ser (assay numbering)

Classified as

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: All Variants: Abnormal function

+3 more calibrations

PS3 moderateFunctionally abnormalInvestigator-provided functional classes: Abnormal function

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: Missense Variants Only: Abnormal function

PS3 very strongFunctionally abnormalRUO ExCALIBR calibration: PS3 Very Strong (8)

Protein level

Scores from cell surface expression deep mutational scan of KCNH2 in HEK293T cells

Cell surface expression deep mutational scan of KCNH2 in HEK293T cells

• Gene: KCNH2
• Assay type: Reporter
• Mechanism: Protein localization to plasma membrane
• Model system: Immortalized human cells (Homo sapiens)
• Score: 0.00 · p.Gly604Ser (assay numbering)

Classified as

PS3 strongFunctionally abnormalInvestigator-provided functional classes: Loss of function

+2 more calibrations

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: Missense Variants Only: Loss of function

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: All Variants: Loss of function

Protein level

Scores from cell surface expression deep mutational scan of KCNH2 in HEK293T cells

Cell surface expression deep mutational scan of KCNH2 in HEK293T cells

• Gene: KCNH2
• Assay type: Reporter
• Mechanism: Protein localization to plasma membrane
• Model system: Immortalized human cells (Homo sapiens)
• Score: 0.00 · p.Gly604Ser (assay numbering)

Classified as

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: All Variants: Loss of function

+3 more calibrations

PS3 strongFunctionally abnormalInvestigator-provided functional classes: Loss of function

PS3 moderateFunctionally abnormalIGVF Coding Variant Focus Group -- Controls: Missense Variants Only: Loss of function

PS3 strongFunctionally abnormalRUO ExCALIBR calibration: PS3 Strong (4)

Other links and lift over

hg19: chr7-150648669;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar