5-45261958-G-A

Position:

• chr5-45261958-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM2 PP2 BP4_Strong

The NM_021072.4(HCN1):​c.2636C>T​(p.Pro879Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,856 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. P879T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: HCN1 NM_021072.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.37

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), HCN1. . Gene score misZ 3.6647 (greater than the threshold 3.09). Trascript score misZ 3.2427 (greater than threshold 3.09). GenCC has associacion of gene with generalized epilepsy with febrile seizures plus, type 10, undetermined early-onset epileptic encephalopathy, developmental and epileptic encephalopathy, 24, generalized epilepsy with febrile seizures plus.
• BP4: Computational evidence support a benign effect (MetaRNN=0.05175969).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HCN1	NM_021072.4	c.2636C>T	p.Pro879Leu	missense_variant	8/8	ENST00000303230.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HCN1	ENST00000303230.6	c.2636C>T	p.Pro879Leu	missense_variant	8/8	1	NM_021072.4	P2
HCN1	ENST00000673735.1	c.*861C>T		3_prime_UTR_variant	9/9			A2
HCN1	ENST00000637305.1	n.1799C>T		non_coding_transcript_exon_variant	7/7	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250932 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135864

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461856 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727228

Gnomad4 AFR exome AF: 0.00

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

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

Labcorp Genetics (formerly Invitae), Labcorp

Dec 19, 2023

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 879 of the HCN1 protein (p.Pro879Leu). This variant is present in population databases (rs774478577, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with HCN1-related conditions. 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 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.070
BayesDel_addAF	Uncertain	0.050	T
BayesDel_noAF	Benign	-0.17
CADD	Benign	20
DANN	Benign	0.82
DEOGEN2	Benign	0.14	T
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.27
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.71	T
M_CAP	Benign	0.070	D
MetaRNN	Benign	0.052	T
MetaSVM	Uncertain	0.025	D
MutationAssessor	Benign	0.34	N
MutationTaster	Benign	0.99	D
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-2.3	N
REVEL	Uncertain	0.31
Sift	Benign	0.24	T
Sift4G	Benign	0.41	T
Polyphen		0.0	B
Vest4		0.060
MutPred		0.18		Loss of methylation at K883 (P = 0.0417);
MVP		0.54
MPC		0.39
ClinPred		0.074	T
GERP RS		3.1
Varity_R		0.061
gMVP		0.20

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: rs774478577; hg19: chr5-45262060;