NM_021072.4:c.1522G>C

Variant names:

• chr5-45303695-C-G
• rs180790607
• NM_021072.4:c.1522G>C

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM2 PM5 BP4

The NM_021072.4(HCN1):​c.1522G>C​(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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. 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: Not reported in ClinVar
• Conservation: PhyloP100: 2.03
• Publications: 6 publications found

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]

HCN1 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 24

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• generalized epilepsy with febrile seizures plus

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• generalized epilepsy with febrile seizures plus, type 10

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 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 VariationId is 530453.
• BP4: Computational evidence support a benign effect (MetaRNN=0.2827183).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_021072.4. 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
	HCN1	NM_021072.4	MANE Select	c.1522G>C	p.Val508Leu	missense	Exon 6 of 8	NP_066550.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HCN1	ENST00000303230.6	TSL:1 MANE Select	c.1522G>C	p.Val508Leu	missense	Exon 6 of 8	ENSP00000307342.4
	HCN1	ENST00000673735.1		c.1522G>C	p.Val508Leu	missense	Exon 6 of 9	ENSP00000501107.1
	HCN1	ENST00000637305.1	TSL:5	n.685G>C		non_coding_transcript_exon	Exon 5 of 7

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250768 AF XY: 0.00000738

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461382 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726984

⚠️ 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: 33448

American (AMR) AF: 0.00 AC: 0 AN: 44636

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.00 AC: 0 AN: 39674

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111708

Other (OTH) AF: 0.00 AC: 0 AN: 60380

⚠️ 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.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.63
BayesDel_addAF	Uncertain	0.096	D
BayesDel_noAF	Uncertain	0.0
CADD	Uncertain	24
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	0.068	D
MetaRNN	Benign	0.28	T
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Benign	-0.51	N
PhyloP100		2.0
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		0.53	D
GERP RS		5.6
Varity_R		0.31
gMVP		0.69
Mutation Taster		=49/51	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs180790607; hg19: chr5-45303797;