rs773676799

Positions:

• chr15-73367690-G-A
• chr15-73367690-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4 BS2

The NM_005477.3(HCN4):​c.581C>T​(p.Ala194Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000749 in 1,601,672 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 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. A194L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: HCN4 NM_005477.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.62

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]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.29073948).
• BS2: High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HCN4	NM_005477.3	c.581C>T	p.Ala194Val	missense_variant	1/8	ENST00000261917.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HCN4	ENST00000261917.4	c.581C>T	p.Ala194Val	missense_variant	1/8	1	NM_005477.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152086 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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

GnomAD3 exomes AF: 0.00000861 AC: 2 AN: 232162 Hom.: 0 AF XY: 0.00000778 AC XY: 1 AN XY: 128458

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000585

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS 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: 0.00000552 AC: 8 AN: 1449586 Hom.: 0 Cov.: 32 AF XY: 0.00000277 AC XY: 2 AN XY: 721496

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000672

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: 0.00000270

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152086 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74290

Gnomad4 AFR AF: 0.0000724

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ExAC AF: 0.0000168 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Brugada syndrome 8 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 18, 2022

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. 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. ClinVar contains an entry for this variant (Variation ID: 578100). This variant has not been reported in the literature in individuals affected with HCN4-related conditions. This variant is present in population databases (rs773676799, gnomAD 0.006%). This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 194 of the HCN4 protein (p.Ala194Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.083
BayesDel_addAF	Benign	-0.067	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.23	T
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.20
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Benign	0.70	T
M_CAP	Pathogenic	0.32	D
MetaRNN	Benign	0.29	T
MetaSVM	Uncertain	0.042	D
MutationAssessor	Benign	0.34	N
MutationTaster	Benign	0.93	N
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.82	N
REVEL	Benign	0.29
Sift	Benign	0.19	T
Sift4G	Benign	0.21	T
Polyphen		0.60	P
Vest4		0.16
MutPred		0.27		Loss of sheet (P = 0.0457);
MVP		0.93
MPC		1.1
ClinPred		0.16	T
GERP RS		1.2
Varity_R		0.073
gMVP		0.27

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

Other links and lift over

dbSNP: rs773676799; hg19: chr15-73660031;