rs180790607

chr5-45303695-C-Achr5-45303695-C-Gchr5-45303695-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM2 PM5 PP2 BP4

The NM_021072.4(HCN1):c.1522G>T(p.Val508Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,382 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V508M) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HCN1 NM_021072.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.03

Genes affected

HCN1 (HGNC:4845): (hyperpolarization activated cyclic nucleotide gated potassium channel 1) The membrane protein encoded by this gene is a hyperpolarization-activated cation channel that contributes to the native pacemaker currents in heart and neurons. The encoded protein can homodimerize or heterodimerize with other pore-forming subunits to form a potassium channel. This channel may act as a receptor for sour tastes. [provided by RefSeq, Oct 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr5-45303695-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 530453.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Uncertain_significance=1}.
• PP2: Missense variant where missense usually causes diseases, HCN1
• BP4: Computational evidence support a benign effect (MetaRNN=0.2805975).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HCN1	NM_021072.4	c.1522G>T	p.Val508Leu	missense_variant	6/8	ENST00000303230.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HCN1	ENST00000303230.6	c.1522G>T	p.Val508Leu	missense_variant	6/8	1	NM_021072.4	P2
HCN1	ENST00000673735.1	c.1522G>T	p.Val508Leu	missense_variant	6/9			A2
HCN1	ENST00000637305.1	n.685G>T		non_coding_transcript_exon_variant	5/7	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461382 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726984

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 31, 2020

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 HCN1 protein function. This variant has not been reported in the literature in individuals with HCN1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with leucine at codon 508 of the HCN1 protein (p.Val508Leu). The valine residue is highly conserved and there is a small physicochemical difference between valine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.63
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.53	D
Eigen	Benign	-0.097
Eigen_PC	Benign	0.14
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.89	D
M_CAP	Benign	0.066	D
MetaRNN	Benign	0.28	T
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Benign	-0.51	N
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-1.4	N
REVEL	Uncertain	0.38
Sift	Benign	0.29	T
Sift4G	Benign	0.13	T
Polyphen		0.0030	B
Vest4		0.42
MutPred		0.50		Loss of methylation at K510 (P = 0.0865);
MVP		0.96
MPC		2.7
ClinPred		0.81	D
GERP RS		5.6
Varity_R		0.31
gMVP		0.69

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs180790607; hg19: chr5-45303797; COSMIC: COSV57495369;