11-2662013-C-A

Position:

• chr11-2662013-C-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_000218.3(KCNQ1):​c.1446C>A​(p.Thr482=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: KCNQ1 NM_000218.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.639

Genes affected

KCNQ1 (HGNC:6294): (potassium voltage-gated channel subfamily Q member 1) This gene encodes a voltage-gated potassium channel required for repolarization phase of the cardiac action potential. This protein can form heteromultimers with two other potassium channel proteins, KCNE1 and KCNE3. Mutations in this gene are associated with hereditary long QT syndrome 1 (also known as Romano-Ward syndrome), Jervell and Lange-Nielsen syndrome, and familial atrial fibrillation. This gene exhibits tissue-specific imprinting, with preferential expression from the maternal allele in some tissues, and biallelic expression in others. This gene is located in a region of chromosome 11 amongst other imprinted genes that are associated with Beckwith-Wiedemann syndrome (BWS), and itself has been shown to be disrupted by chromosomal rearrangements in patients with BWS. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Aug 2011]

KCNQ1OT1 (HGNC:6295): (KCNQ1 opposite strand/antisense transcript 1) Human chromosomal region 11p15.5 contains two clusters of epigenetically-regulated genes that are expressed from only one chromosome in a parent-of-origin manner. Each cluster, or imprinted domain, is regulated by a functionally independent imprinting control region (ICR). The human CDKN1C/KCNQ1OT1 domain is regulated by an ICR located in an intron of KCNQ1, and contains at least eight genes that are expressed exclusively or preferentially from the maternally-inherited allele. The DNA of the ICR is specifically methylated on the maternally-inherited chromosome, and unmethylated on the paternally-inherited chromosome. The ICR contains the promoter of the KCNQ1OT1 gene that is exclusively expressed from the paternal allele. The KCNQ1OT1 transcript is the antisense to the KCNQ1 gene and is a unspliced long non-coding RNA. It interacts with chromatin and regulates transcription of multiple target genes through epigenetic modifications. The transcript is abnormally expressed from both chromosomes in most patients with Beckwith-Wiedemann syndrome, and the transcript also plays an important role in colorectal carcinogenesis. [provided by RefSeq, Apr 2012]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.36).
• BP7: Synonymous conserved (PhyloP=0.639 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNQ1	NM_000218.3	c.1446C>A	p.Thr482=	synonymous_variant	11/16	ENST00000155840.12	NP_000209.2
KCNQ1OT1	NR_002728.3	n.37986G>T		non_coding_transcript_exon_variant	1/1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNQ1	ENST00000155840.12	c.1446C>A	p.Thr482=	synonymous_variant	11/16	1	NM_000218.3	ENSP00000155840	P1
KCNQ1OT1	ENST00000710656.1	n.376-20898G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461882 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727244

Gnomad4 AFR exome AF: 0.00

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.36
CADD	Benign	8.5
DANN	Benign	0.77

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: rs1060503982; hg19: chr11-2683243;