rs745880598

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_005477.3(HCN4):c.724C>T(p.Arg242Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000155 in 1,613,938 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R242L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

HCN4
NM_005477.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 2.68

Publications

0 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 -4 ACMG points.

BS2

High AC in GnomAd4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HCN4	NM_005477.3 link	c.724C>T	p.Arg242Cys	missense_variant	Exon 1 of 8	ENST00000261917.4	NP_005468.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HCN4	ENST00000261917.4 link	c.724C>T	p.Arg242Cys	missense_variant	Exon 1 of 8	1	NM_005477.3	ENSP00000261917.3

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152196

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000265

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000319

AC:

AN:

251140

AF XY:

0.0000442

show subpopulations

Gnomad AFR exome

AF:

0.000246

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461742

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727178

show subpopulations

African (AFR)

AF:

0.000269

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53308

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111992

Other (OTH)

AF:

0.0000331

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.507

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:

0.0000723

AC:

AN:

152196

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74360

show subpopulations

African (AFR)

AF:

0.000265

AC:

AN:

41466

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.484

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:

0.0000658

Hom.:

Bravo

AF:

0.0000680

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Dec 12, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Aug 26, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

not specified

Uncertain:1

Oct 16, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: HCN4 c.724C>T (p.Arg242Cys) results in a non-conservative amino acid change located in the Ion transport N-terminal domain of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 3.2e-05 in 251140 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.724C>T has been reported in the literature in a family affected with hypertrophic cardiomyopathy, however authors classified the variant as VUS (example: Robyns_2017) . These report(s) do not provide unequivocal conclusions about association of the variant with Sick Sinus Syndrome 2. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 29255176). ClinVar contains an entry for this variant (Variation ID: 240173). Based on the evidence outlined above, the variant was classified as uncertain significance.

Brugada syndrome 8

Uncertain:1

Oct 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 242 of the HCN4 protein (p.Arg242Cys). This variant is present in population databases (rs745880598, gnomAD 0.02%). 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: 240173). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt HCN4 protein function. 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.

Hypertrophic cardiomyopathy

Uncertain:1

Apr 30, 2017

Center for Human Genetics, University of Leuven

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cardiovascular phenotype

Uncertain:1

Mar 17, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R242C variant (also known as c.724C>T), located in coding exon 1 of the HCN4 gene, results from a C to T substitution at nucleotide position 724. The arginine at codon 242 is replaced by cysteine, an amino acid with highly dissimilar properties. This alteration has been reported in a primary arrhythmia and cardiomyopathy cohort (Robyns T et al. Eur J Hum Genet, 2017 12;25:1313-1323). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.64

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.15

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.83

Eigen

Uncertain

0.39

Eigen_PC

Uncertain

0.41

FATHMM_MKL

Uncertain

0.84

LIST_S2

Pathogenic

0.98

M_CAP

Uncertain

0.10

MetaRNN

Uncertain

0.47

MetaSVM

Benign

-0.28

MutationAssessor

Benign

1.0

PhyloP100

2.7

PrimateAI

Uncertain

0.75

PROVEAN

Uncertain

-4.0

REVEL

Uncertain

0.56

Sift

Uncertain

0.025

Sift4G

Uncertain

0.037

Vest4

0.44

ClinPred

0.35

GERP RS

4.8

Varity_R

0.27

gMVP

0.90

Mutation Taster

=20/80

disease causing

(source)

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

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