Genetic Variant NM_005477.3:c.434C>T (chr15-73367837-G-A) – ACMG Classification: Likely_benign (-5 pts)

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4BS2

The NM_005477.3(HCN4):c.434C>T(p.Pro145Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000397 in 1,260,142 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000060 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000037 ( 0 hom. )

Consequence

HCN4
NM_005477.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 2.16

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 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.32021588).

BS2

High AC in GnomAd4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HCN4	NM_005477.3 link	c.434C>T	p.Pro145Leu	missense_variant	Exon 1 of 8	ENST00000261917.4	NP_005468.1	Q9Y3Q4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HCN4	ENST00000261917.4 link	c.434C>T	p.Pro145Leu	missense_variant	Exon 1 of 8	1	NM_005477.3	ENSP00000261917.3		Q9Y3Q4

Frequencies

GnomAD3 genomes

AF:

0.0000596

AC:

AN:

150994

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000132

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:

0.0000887

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000370

AC:

AN:

1109148

Hom.:

Cov.:

AF XY:

0.0000338

AC XY:

AN XY:

532428

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000104

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000426

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000596

AC:

AN:

150994

Hom.:

Cov.:

AF XY:

0.0000542

AC XY:

AN XY:

73736

show subpopulations

Gnomad4 AFR

AF:

0.0000242

Gnomad4 AMR

AF:

0.000132

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000887

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000382

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Brugada syndrome 8

Uncertain:1

Jan 25, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 145 of the HCN4 protein (p.Pro145Leu). This variant is not present in population databases (gnomAD no frequency). 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: 573242). 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

Aug 11, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.P145L variant (also known as c.434C>T), located in coding exon 1 of the HCN4 gene, results from a C to T substitution at nucleotide position 434. The proline at codon 145 is replaced by leucine, an amino acid with similar properties. 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

Benign

0.094

BayesDel_addAF

Uncertain

0.11

BayesDel_noAF

Uncertain

-0.080

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.33

Eigen

Benign

-0.20

Eigen_PC

Benign

-0.086

FATHMM_MKL

Uncertain

0.87

LIST_S2

Benign

0.62

M_CAP

Pathogenic

0.96

MetaRNN

Benign

0.32

MetaSVM

Uncertain

0.74

MutationAssessor

Benign

1.6

PrimateAI

Pathogenic

0.94

PROVEAN

Benign

-1.3

REVEL

Uncertain

0.46

Sift

Uncertain

0.0040

Sift4G

Uncertain

0.0030

Polyphen

0.054

Vest4

0.15

MutPred

0.22

Loss of glycosylation at P146 (P = 0.0882);

MVP

0.91

MPC

1.1

ClinPred

0.71

GERP RS

4.0

Varity_R

0.068

gMVP

0.54

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over