1-210683304-T-C

Variant names:

• chr1-210683304-T-C
• rs769883770
• NM_172362.3:c.2947A>G

Variant summary

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

The NM_172362.3(KCNH1):​c.2947A>G​(p.Arg983Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNH1 NM_172362.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.00

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 the KCNH1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 27 curated pathogenic missense variants (we use a threshold of 10). The gene has 72 curated benign missense variants. Gene score misZ: 3.8156 (above the threshold of 3.09). Trascript score misZ: 5.0674 (above the threshold of 3.09). GenCC associations: The gene is linked to KCNH1 associated disorder, Zimmermann-Laband syndrome, Temple-Baraitser syndrome, Zimmermann-Laband syndrome 1.
• BP4: Computational evidence support a benign effect (MetaRNN=0.28062913).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNH1	NM_172362.3	c.2947A>G	p.Arg983Gly	missense_variant	Exon 11 of 11	ENST00000271751.10	NP_758872.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNH1	ENST00000271751.10	c.2947A>G	p.Arg983Gly	missense_variant	Exon 11 of 11	2	NM_172362.3	ENSP00000271751.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Apr 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 983 of the KCNH1 protein (p.Arg983Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with KCNH1-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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNH1 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.020
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.23	T;.;.;T
Eigen	Benign	-0.073
Eigen_PC	Benign	0.13
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.87	D;.;D;D
M_CAP	Uncertain	0.15	D
MetaRNN	Benign	0.28	T;T;T;T
MetaSVM	Uncertain	0.68	D
MutationAssessor	Benign	1.0	L;.;.;.
PrimateAI	Benign	0.44	T
PROVEAN	Benign	0.81	N;.;.;.
REVEL	Uncertain	0.42
Sift	Benign	0.11	T;.;.;.
Sift4G	Benign	0.16	T;.;.;.
Polyphen		0.0	B;.;.;.
Vest4		0.10
MutPred		0.15		Loss of stability (P = 0.0308);.;.;.;
MVP		0.96
MPC		0.21
ClinPred		0.82	D
GERP RS		5.1
Varity_R		0.14
gMVP		0.31

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: rs769883770; hg19: chr1-210856646;