1-40784129-T-TCCCCCGCCCGGGGACGC

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_004700.4(KCNQ4):c.44_60dup(p.Ala21ProfsTer9) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNQ4 NM_004700.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 1.03

Genes affected

KCNQ4 (HGNC:6298): (potassium voltage-gated channel subfamily Q member 4) The protein encoded by this gene forms a potassium channel that is thought to play a critical role in the regulation of neuronal excitability, particularly in sensory cells of the cochlea. The current generated by this channel is inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. The encoded protein can form a homomultimeric potassium channel or possibly a heteromultimeric channel in association with the protein encoded by the KCNQ3 gene. Defects in this gene are a cause of nonsyndromic sensorineural deafness type 2 (DFNA2), an autosomal dominant form of progressive hearing loss. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 63 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-40784129-T-TCCCCCGCCCGGGGACGC is Pathogenic according to our data. Variant chr1-40784129-T-TCCCCCGCCCGGGGACGC is described in ClinVar as [Pathogenic]. Clinvar id is 2993508.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ4	NM_004700.4	c.44_60dup	p.Ala21ProfsTer9	frameshift_variant	1/14	ENST00000347132.10
KCNQ4	NM_172163.3	c.44_60dup	p.Ala21ProfsTer9	frameshift_variant	1/13
KCNQ4	XM_047434057.1	c.44_60dup	p.Ala21ProfsTer9	frameshift_variant	1/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ4	ENST00000347132.10	c.44_60dup	p.Ala21ProfsTer9	frameshift_variant	1/14	1	NM_004700.4	P2
KCNQ4	ENST00000509682.6	c.44_60dup	p.Ala21ProfsTer9	frameshift_variant	1/13	5		A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 11

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 20, 2023

This sequence change creates a premature translational stop signal (p.Ala21Profs*9) in the KCNQ4 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KCNQ4 are known to be pathogenic (PMID: 23717403). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with KCNQ4-related conditions. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1647180436; hg19: chr1-41249801;