1-210683339-A-C

Position:

• chr1-210683339-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_172362.3(KCNH1):​c.2912T>G​(p.Phe971Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,886 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. F971L) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: KCNH1 NM_172362.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.78

Genes affected

KCNH1 (HGNC:6250): (potassium voltage-gated channel subfamily H member 1) Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a member of the potassium channel, voltage-gated, subfamily H. This member is a pore-forming (alpha) subunit of a voltage-gated non-inactivating delayed rectifier potassium channel. It is activated at the onset of myoblast differentiation. The gene is highly expressed in brain and in myoblasts. Overexpression of the gene may confer a growth advantage to cancer cells and favor tumor cell proliferation. Alternative splicing of this gene results in two transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 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), KCNH1. . Gene score misZ 3.8156 (greater than the threshold 3.09). Trascript score misZ 5.0674 (greater than threshold 3.09). GenCC has associacion of gene with KCNH1 associated disorder, Zimmermann-Laband syndrome, Temple-Baraitser syndrome, Zimmermann-Laband syndrome 1.
• BP4: Computational evidence support a benign effect (MetaRNN=0.33362094).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNH1	NM_172362.3	c.2912T>G	p.Phe971Cys	missense_variant	11/11	ENST00000271751.10	NP_758872.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNH1	ENST00000271751.10	c.2912T>G	p.Phe971Cys	missense_variant	11/11	2	NM_172362.3	ENSP00000271751.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461886 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 727244

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 13, 2022	This variant has not been reported in the literature in individuals affected with KCNH1-related conditions. 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 KCNH1 protein function. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces phenylalanine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 971 of the KCNH1 protein (p.Phe971Cys). -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Mar 05, 2024	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Uncertain	0.089	D
BayesDel_noAF	Benign	-0.11
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.34	T;.;.;T
Eigen	Uncertain	0.25
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.79	T;.;T;T
M_CAP	Pathogenic	0.34	D
MetaRNN	Benign	0.33	T;T;T;T
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	0.34	N;.;.;.
MutationTaster	Benign	0.61	D;D
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-1.5	N;.;.;.
REVEL	Uncertain	0.41
Sift	Benign	0.047	D;.;.;.
Sift4G	Benign	0.26	T;.;.;.
Polyphen		0.99	D;.;.;.
Vest4		0.17
MutPred		0.14		Loss of glycosylation at S974 (P = 0.2362);.;.;.;
MVP		0.98
MPC		0.59
ClinPred		0.83	D
GERP RS		3.9
Varity_R		0.090
gMVP		0.34

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: rs1681319872; hg19: chr1-210856681;