NM_005477.3:c.2197G>A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_005477.3(HCN4):c.2197G>A(p.Val733Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000929 in 1,603,796 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V733A) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000098 ( 0 hom. )

Consequence

HCN4
NM_005477.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 3.10

Publications

1 publications found

Variant links:

Genes affected

HCN4 (HGNC:16882): (hyperpolarization activated cyclic nucleotide gated potassium channel 4) This gene encodes a member of the hyperpolarization-activated cyclic nucleotide-gated potassium channels. The encoded protein shows slow kinetics of activation and inactivation, and is necessary for the cardiac pacemaking process. This channel may also mediate responses to sour stimuli. Mutations in this gene have been linked to sick sinus syndrome 2, also known as atrial fibrillation with bradyarrhythmia or familial sinus bradycardia. Two pseudogenes have been identified on chromosome 15. [provided by RefSeq, Oct 2008]

HCN4 Gene-Disease associations (from GenCC):

sick sinus syndrome 2, autosomal dominant
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
Brugada syndrome 8
Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
familial sick sinus syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
familial thoracic aortic aneurysm and aortic dissection
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
Brugada syndrome 1
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

HCN4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.2265509).

BS2

High AC in GnomAd4 at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HCN4	NM_005477.3 link	c.2197G>A	p.Val733Ile	missense_variant	Exon 8 of 8	ENST00000261917.4	NP_005468.1	Q9Y3Q4
HCN4	XM_011521148.3 link	c.979G>A	p.Val327Ile	missense_variant	Exon 7 of 7		XP_011519450.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HCN4	ENST00000261917.4 link	c.2197G>A	p.Val733Ile	missense_variant	Exon 8 of 8	1	NM_005477.3	ENSP00000261917.3		Q9Y3Q4

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152198

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000588

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000787

AC:

AN:

241316

AF XY:

0.0000913

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000144

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000978

AC:

142

AN:

1451480

Hom.:

Cov.:

AF XY:

0.000104

AC XY:

AN XY:

722498

show subpopulations

African (AFR)

AF:

0.000119

AC:

AN:

33476

American (AMR)

AF:

0.0000895

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

43174

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000112

AC:

124

AN:

1111928

Other (OTH)

AF:

0.000133

AC:

AN:

60330

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.476

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152316

Hom.:

Cov.:

AF XY:

0.0000671

AC XY:

AN XY:

74490

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41566

American (AMR)

AF:

0.00

AC:

AN:

15312

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68014

Other (OTH)

AF:

0.000473

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.454

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000120

Hom.:

Bravo

AF:

0.0000756

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000659

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000296

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Jul 20, 2015

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Oct 30, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Has not been previously published as pathogenic or benign to our knowledge; In silico analysis supports that this missense variant does not alter protein structure/function -

Cardiac arrest

Uncertain:1

Nov 16, 2015

Blueprint Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sick sinus syndrome 2, autosomal dominant;C2751083:Brugada syndrome 8;C5561983:Epilepsy, idiopathic generalized, susceptibility to, 18

Uncertain:1

Aug 25, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Brugada syndrome 8

Uncertain:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 733 of the HCN4 protein (p.Val733Ile). This variant is present in population databases (rs376631391, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with HCN4-related conditions. ClinVar contains an entry for this variant (Variation ID: 222648). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt HCN4 protein function with a negative predictive value of 95%. 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. -

Cardiovascular phenotype

Uncertain:1

Nov 02, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.V733I variant (also known as c.2197G>A), located in coding exon 8 of the HCN4 gene, results from a G to A substitution at nucleotide position 2197. The valine at codon 733 is replaced by isoleucine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not specified

Benign:1

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

BS1, BP4, BP5 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.27

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.24

Eigen

Benign

0.068

Eigen_PC

Benign

0.074

FATHMM_MKL

Uncertain

0.78

LIST_S2

Uncertain

0.87

M_CAP

Benign

0.069

MetaRNN

Benign

0.23

MetaSVM

Uncertain

-0.21

MutationAssessor

Benign

2.0

PhyloP100

3.1

PrimateAI

Uncertain

0.54

PROVEAN

Benign

-0.59

REVEL

Benign

0.29

Sift

Benign

0.042

Sift4G

Uncertain

0.059

Polyphen

0.96

Vest4

0.26

MVP

0.85

MPC

0.14

ClinPred

0.050

GERP RS

3.5

Varity_R

0.090

gMVP

0.69

Mutation Taster

=88/12

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over