11-2445250-ACGCGCCCAT-ACGCGCCCATCGCGCCCAT
Variant summary
Our verdict is Benign. Variant got -7 ACMG points: 2P and 9B. PM4BP6BS1BS2
The NM_000218.3(KCNQ1):c.160_168dupATCGCGCCC(p.Ile54_Pro56dup) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00173 in 1,199,452 control chromosomes in the GnomAD database, including 33 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000218.3 conservative_inframe_insertion
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -7 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
KCNQ1 | NM_000218.3 | c.160_168dupATCGCGCCC | p.Ile54_Pro56dup | conservative_inframe_insertion | Exon 1 of 16 | ENST00000155840.12 | NP_000209.2 | |
KCNQ1 | NM_001406836.1 | c.160_168dupATCGCGCCC | p.Ile54_Pro56dup | conservative_inframe_insertion | Exon 1 of 15 | NP_001393765.1 | ||
KCNQ1 | NM_001406838.1 | c.160_168dupATCGCGCCC | p.Ile54_Pro56dup | conservative_inframe_insertion | Exon 1 of 11 | NP_001393767.1 | ||
KCNQ1 | NM_001406837.1 | c.-203_-195dupATCGCGCCC | 5_prime_UTR_variant | Exon 1 of 17 | NP_001393766.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
KCNQ1 | ENST00000155840.12 | c.160_168dupATCGCGCCC | p.Ile54_Pro56dup | conservative_inframe_insertion | Exon 1 of 16 | 1 | NM_000218.3 | ENSP00000155840.2 | ||
KCNQ1 | ENST00000646564.2 | c.160_168dupATCGCGCCC | p.Ile54_Pro56dup | conservative_inframe_insertion | Exon 1 of 11 | ENSP00000495806.2 | ||||
KCNQ1 | ENST00000496887.7 | c.24-125_24-117dupATCGCGCCC | intron_variant | Intron 1 of 15 | 5 | ENSP00000434560.2 | ||||
KCNQ1 | ENST00000345015.4 | n.-72_-71insCGCGCCCAT | upstream_gene_variant | 1 |
Frequencies
GnomAD3 genomes AF: 0.00880 AC: 1305AN: 148264Hom.: 21 Cov.: 32
GnomAD3 exomes AF: 0.000258 AC: 2AN: 7752Hom.: 0 AF XY: 0.000207 AC XY: 1AN XY: 4828
GnomAD4 exome AF: 0.000730 AC: 767AN: 1051082Hom.: 12 Cov.: 30 AF XY: 0.000659 AC XY: 332AN XY: 503788
GnomAD4 genome AF: 0.00881 AC: 1307AN: 148370Hom.: 21 Cov.: 32 AF XY: 0.00845 AC XY: 612AN XY: 72398
ClinVar
Submissions by phenotype
not specified Benign:3
Variant summary: KCNQ1 c.160_168dupATCGCGCCC (p.Ile54_Pro56dup) results in an in-frame duplication that is predicted to duplicate three amino acids into the encoded protein. The variant allele was found at a frequency of 0.0017 in 1200626 control chromosomes, predominantly at a frequency of 0.03 within the African or African-American subpopulation in the gnomAD database (v4), including 31 homozygotes. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 300 fold of the estimated maximal expected allele frequency for a pathogenic variant in KCNQ1 causing Arrhythmia phenotype (0.0001). c.160_168dupATCGCGCCC has been reported in the literature in individuals affected with Arrhythmia as well as in control population (e.g. Abraham_2010, Berge_2008, Ackerman_2003, Tester_2005_01, Kapa_2009, Hassnan_2017, Millat_2014). In a family with familial atrial fibrillation, this variant was reported with inconclusive co-segregation of this variant with disease (Abraham_2010). This family however, was not comprehensively screened for mutations in all susceptibility genes. Co-occurrences with other pathogenic variants have been reported (KCNQ1 c.674C>T, p.Ser225Leu; KCNH2 c.1841C>T, p.Ala614Val) in our internal database. In vitro functional study detected partial defect of the channel properties (Abraham_2010), suggesting that it could be a functional polymorphism.. The following publications have been ascertained in the context of this evaluation (PMID: 14661677, 17210839, 15913580, 19841300, 19646991, 18752142, 22947121, 22818067, 24687331, 28438721). ClinVar contains an entry for this variant (Variation ID: 42487). Based on the evidence outlined above, the variant was classified as benign. -
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p.Ile54_Pro56dup in Exon 1 of KCNQ1: This variant is not expected to have clinic al significance because it has been identified in 2.9% (250/8370) of African ch romosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitu te.org; dbSNP rs561562768). It has been reported in two individuals with cardia c arrhythmias (1/182 LQTS, Berge 2008; 1/231 AF, Abraham 2010) and segregated in three affected individuals in one family, though phenotypes were unknown in 2 o ther mutation carriers (Abraham 2010). In addition, one study demonstrated some alteration of channel properties (Abraham 2010) although this study was only in vitro such that correlation to a clinical phenotype was not possible. This varia nt was also identified in several healthy control cohorts (0.3% 4/1488 chromosom es, Ackerman 2003; 1/364 chromosomes, Arnestad 2007; 2.1% (2/94) African-America n control chromosomes, Abraham 2010) and is now listed in the KCNQ1 database as a benign variant (http://www.fsm.it/cardmoc/kvlqt1poly.htm). In summary, given t he high frequency of the variant in spite of the reports in the literature, this variant is benign for a reasonably penetrant disease variant and insufficient b iological evidence for a clinically relevant impact to protein function, we have classified this variant as likely benign. -
not provided Benign:3
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This variant is associated with the following publications: (PMID: 18752142, 14661677, 17210839, 19646991, 28438721, 32048431, 30847666) -
KCNQ1: BS1, BS2 -
Cardiovascular phenotype Uncertain:2
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Atrial fibrillation, familial, 3 Pathogenic:1
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KCNQ1-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Ventricular fibrillation Benign:1
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Long QT syndrome Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at