1-40822388-C-T

Variant names:

• chr1-40822388-C-T
• rs779107599
• NM_004700.4:c.1116C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP7

The NM_004700.4(KCNQ4):​c.1116C>T​(p.Ile372Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,458,574 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. I372I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: KCNQ4 NM_004700.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.612
• Publications: 0 publications found

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]

KCNQ4 Gene-Disease associations (from GenCC):

• autosomal dominant nonsyndromic hearing loss 2A

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, PanelApp Australia
• nonsyndromic genetic hearing loss

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hearing loss disorder

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP7: Synonymous conserved (PhyloP=0.612 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004700.4. 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
	KCNQ4	NM_004700.4	MANE Select	c.1116C>T	p.Ile372Ile	synonymous	Exon 8 of 14	NP_004691.2
	KCNQ4	NM_172163.3		c.1116C>T	p.Ile372Ile	synonymous	Exon 8 of 13	NP_751895.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ4	ENST00000347132.10	TSL:1 MANE Select	c.1116C>T	p.Ile372Ile	synonymous	Exon 8 of 14	ENSP00000262916.6
	KCNQ4	ENST00000509682.6	TSL:5	c.1116C>T	p.Ile372Ile	synonymous	Exon 8 of 13	ENSP00000423756.2
	KCNQ4	ENST00000443478.3	TSL:5	c.801C>T	p.Ile267Ile	synonymous	Exon 7 of 13	ENSP00000406735.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1458574 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 725810

⚠️ 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: 33402

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.00 AC: 0 AN: 39678

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86196

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53102

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1109344

Other (OTH) AF: 0.00 AC: 0 AN: 60288

⚠️ 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
BayesDel_noAF	Benign	-0.30
CADD	Benign	7.4
DANN	Benign	0.82
PhyloP100		0.61
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs779107599; hg19: chr1-41288060;