rs1234068441

Positions:

• chr5-45353141-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_021072.4(HCN1):​c.1336G>A​(p.Glu446Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging 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. E446D) has been classified as Uncertain significance.

• 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: 7.90

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 5 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.893

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HCN1	NM_021072.4	c.1336G>A	p.Glu446Lys	missense_variant	5/8	ENST00000303230.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HCN1	ENST00000303230.6	c.1336G>A	p.Glu446Lys	missense_variant	5/8	1	NM_021072.4	P2
HCN1	ENST00000673735.1	c.1336G>A	p.Glu446Lys	missense_variant	5/9			A2
HCN1	ENST00000637305.1	n.499G>A		non_coding_transcript_exon_variant	4/7	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250410 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135338

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

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: 6.85e-7 AC: 1 AN: 1459872 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 726286

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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

Aug 16, 2022

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 expected to disrupt HCN1 protein function. 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. ClinVar contains an entry for this variant (Variation ID: 461359). This variant has not been reported in the literature in individuals affected with HCN1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 446 of the HCN1 protein (p.Glu446Lys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.73	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-3.9	D
REVEL	Pathogenic	0.87
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.98	D
Vest4		0.85
MutPred		0.56		Gain of ubiquitination at E446 (P = 0.0177);
MVP		0.99
MPC		1.8
ClinPred		0.99	D
GERP RS		6.0
Varity_R		0.91
gMVP		0.88

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: rs1234068441; hg19: chr5-45353243; COSMIC: COSV57513450;