chr15-73322686-C-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_005477.3(HCN4):c.3407G>T(p.Gly1136Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,433,906 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1136S) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 7.0e-7 ( 0 hom. )

Consequence

HCN4
NM_005477.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.24

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: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.16825223).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HCN4	NM_005477.3 link	c.3407G>T	p.Gly1136Val	missense_variant	Exon 8 of 8	ENST00000261917.4	NP_005468.1	Q9Y3Q4
HCN4	XM_011521148.3 link	c.2189G>T	p.Gly730Val	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.3407G>T	p.Gly1136Val	missense_variant	Exon 8 of 8	1	NM_005477.3	ENSP00000261917.3		Q9Y3Q4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

189692

AF XY:

0.00

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.97e-7

AC:

AN:

1433906

Hom.:

Cov.:

AF XY:

0.00000141

AC XY:

AN XY:

710574

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33018

American (AMR)

AF:

0.00

AC:

AN:

40506

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25572

East Asian (EAS)

AF:

0.00

AC:

AN:

38444

South Asian (SAS)

AF:

0.00

AC:

AN:

82616

European-Finnish (FIN)

AF:

0.00

AC:

AN:

49748

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5694

European-Non Finnish (NFE)

AF:

9.10e-7

AC:

AN:

1098934

Other (OTH)

AF:

0.00

AC:

AN:

59374

⚠️ 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.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

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

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Brugada syndrome 8

Uncertain:1

Oct 09, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine with valine at codon 1136 of the HCN4 protein (p.Gly1136Val). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with HCN4-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.084

BayesDel_addAF

Uncertain

0.026

BayesDel_noAF

Benign

-0.20

CADD

Benign

(source)

DANN

Benign

0.92

DEOGEN2

Benign

0.22

Eigen

Benign

-1.0

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.051

LIST_S2

Benign

0.46

M_CAP

Uncertain

0.28

MetaRNN

Benign

0.17

MetaSVM

Uncertain

-0.12

MutationAssessor

Benign

0.69

PhyloP100

1.2

PrimateAI

Uncertain

0.71

PROVEAN

Benign

-0.92

REVEL

Benign

0.20

Sift

Benign

0.19

Sift4G

Benign

0.32

Polyphen

0.0020

Vest4

0.19

MutPred

0.20

Loss of relative solvent accessibility (P = 0.008);

MVP

0.69

MPC

0.80

ClinPred

0.12

GERP RS

1.9

Varity_R

0.069

gMVP

0.42

Mutation Taster

=94/6

polymorphism

(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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over