chr15-73323420-C-G

Variant names:

• chr15-73323420-C-G
• rs191092709
• NM_005477.3:c.2673G>C

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The ENST00000261917.4(HCN4):​c.2673G>C​(p.Ser891Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,452,900 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. S891S) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: HCN4 ENST00000261917.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -5.19
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.87).
• BP7: Synonymous conserved (PhyloP=-5.19 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000261917.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HCN4	NM_005477.3	MANE Select	c.2673G>C	p.Ser891Ser	synonymous	Exon 8 of 8	NP_005468.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HCN4	ENST00000261917.4	TSL:1 MANE Select	c.2673G>C	p.Ser891Ser	synonymous	Exon 8 of 8	ENSP00000261917.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.88e-7 AC: 1 AN: 1452900 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 722286

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

African (AFR) AF: 0.00 AC: 0 AN: 33384

American (AMR) AF: 0.0000229 AC: 1 AN: 43686

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25976

East Asian (EAS) AF: 0.00 AC: 0 AN: 39446

South Asian (SAS) AF: 0.00 AC: 0 AN: 85690

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50458

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5650

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1108624

Other (OTH) AF: 0.00 AC: 0 AN: 59986

⚠️ 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.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 2

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
CADD	Benign	0.022
DANN	Benign	0.38
PhyloP100		-5.2

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

Other links and lift over

dbSNP: rs191092709; hg19: chr15-73615761;