chr8-132174335-G-T

Variant names:

• chr8-132174335-G-T
• rs142144538
• NM_004519.4:c.948C>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Moderate BP6_Moderate BP7

The ENST00000388996.10(KCNQ3):​c.948C>A​(p.Thr316Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. 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 Likely benign (★). Synonymous variant affecting the same amino acid position (i.e. T316T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNQ3 ENST00000388996.10 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.922
• Publications: 0 publications found

Genes affected

KCNQ3 (HGNC:6297): (potassium voltage-gated channel subfamily Q member 3) This gene encodes a protein that functions in the regulation of neuronal excitability. The encoded protein forms an M-channel by associating with the products of the related KCNQ2 or KCNQ5 genes, which both encode integral membrane proteins. M-channel currents are inhibited by M1 muscarinic acetylcholine receptors and are activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 2 (BFNC2), also known as epilepsy, benign neonatal type 2 (EBN2). Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2014]

KCNQ3 Gene-Disease associations (from GenCC):

• seizures, benign familial neonatal, 2

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• benign familial infantile epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• benign neonatal seizures

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• genetic developmental and epileptic encephalopathy

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.45).
• BP6: Variant 8-132174335-G-T is Benign according to our data. Variant chr8-132174335-G-T is described in ClinVar as Likely_benign. ClinVar VariationId is 1560931.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=0.922 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000388996.10. 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
	KCNQ3	NM_004519.4	MANE Select	c.948C>A	p.Thr316Thr	synonymous	Exon 6 of 15	NP_004510.1
	KCNQ3	NM_001204824.2		c.588C>A	p.Thr196Thr	synonymous	Exon 6 of 15	NP_001191753.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNQ3	ENST00000388996.10	TSL:1 MANE Select	c.948C>A	p.Thr316Thr	synonymous	Exon 6 of 15	ENSP00000373648.3
	KCNQ3	ENST00000519445.5	TSL:5	c.948C>A	p.Thr316Thr	synonymous	Exon 6 of 15	ENSP00000428790.1
	KCNQ3	ENST00000521134.6	TSL:2	c.588C>A	p.Thr196Thr	synonymous	Exon 6 of 15	ENSP00000429799.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1399494 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 690314

African (AFR) AF: 0.00 AC: 0 AN: 31610

American (AMR) AF: 0.00 AC: 0 AN: 35792

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25196

East Asian (EAS) AF: 0.00 AC: 0 AN: 35756

South Asian (SAS) AF: 0.00 AC: 0 AN: 79252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49302

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5674

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1078900

Other (OTH) AF: 0.00 AC: 0 AN: 58012

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Benign neonatal seizures (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.45
CADD	Benign	8.6
DANN	Benign	0.72
PhyloP100		0.92

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: rs142144538; hg19: chr8-133186582;