NM_015443.4:c.808_809delCT

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PVS1PP5

The NM_015443.4(KANSL1):c.808_809delCT(p.Leu270ValfsTer11) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000161 in 1,614,018 control chromosomes in the GnomAD database, with no homozygous occurrence. There is a variant allele frequency bias in the population database for this variant (GnomAdExome4), which may indicate mosaicism or somatic mutations in the reference population data. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L270L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 35)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

KANSL1
NM_015443.4 frameshift

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6U:3

Conservation

PhyloP100: 2.03

Publications

3 publications found

Variant links:

Genes affected

KANSL1 (HGNC:24565): (KAT8 regulatory NSL complex subunit 1) This gene encodes a nuclear protein that is a subunit of two protein complexes involved with histone acetylation, the MLL1 complex and the NSL1 complex. The encoded protein has been implicated in a variety of cellular processes including enhancer regulation, cell proliferation, and mitosis. Mutations in this gene are associated with Koolen-de Vries Syndrome. [provided by RefSeq, May 2022]

KANSL1 Gene-Disease associations (from GenCC):

Koolen-de Vries syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), ClinGen
Koolen-de Vries syndrome due to a point mutation
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KANSL1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 17-46171334-CAG-C is Pathogenic according to our data. Variant chr17-46171334-CAG-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 468412.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015443.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KANSL1	NM_015443.4	MANE Select	c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 2 of 15	NP_056258.1
KANSL1	NM_001193466.2		c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 2 of 15	NP_001180395.1
KANSL1	NM_001379198.1		c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 3 of 16	NP_001366127.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KANSL1	ENST00000432791.7	TSL:1 MANE Select	c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 2 of 15	ENSP00000387393.3
KANSL1	ENST00000262419.10	TSL:1	c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 2 of 15	ENSP00000262419.6
KANSL1	ENST00000572904.6	TSL:5	c.808_809delCT	p.Leu270ValfsTer11	frameshift	Exon 2 of 15	ENSP00000461484.1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251458

AF XY:

0.0000368

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000164

AC:

AN:

1461878

Hom.:

AF XY:

0.0000206

AC XY:

AN XY:

727244

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000464

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000153

AC:

AN:

1111998

Other (OTH)

AF:

0.0000331

AC:

AN:

60394

⚠️ 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.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.306

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74322

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41410

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.300

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000843

Hom.:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Koolen-de Vries syndrome

Pathogenic:3Uncertain:2

Jun 23, 2022

Breda Genetics srl

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The variant c.808_809del (p.Leu270Valfs*11) in the KANSL1 gene is reported with conflicting interpretations (pathogenic, likely pathogenic, uncertain) in ClinVar for Koolen-de Vries syndrome (Variation ID: 168412) and as likely pathogenic in the LOVD database v.3.0 (genomic variant: #0000795640). The variant c.808_809del (p.Leu270Valfs*11) has been reported as pathogenic by Niar et al. (2018, PMID: 30293248) in a patient with a diagnosis of Koolen-deVries syndrome, which had developmental delay, intellectual disability, hypotony, ptosis, short stature, and ligamentous laxity. The variant creates a shift in the reading frame which is predicted to result in a premature stop codon 11 amino acids downstream, which is likely to result in a truncated protein or protein loss due to nonsense-mediated messenger decay (NMD). The variant is reported with an estimated allele frequency of 0.00002386 in gnomAD exomes and di 0.00003185 in gnomAD genomes with no homozygous individuals reported.

May 26, 2022

Revvity Omics, Revvity

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 28, 2018

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868].

Aug 31, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:flagged submission

Collection Method:clinical testing

Apr 18, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Inborn genetic diseases

Pathogenic:1

Apr 28, 2023

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.808_809delCT (p.L270Vfs*11) alteration, located in exon 2 (coding exon 1) of the KANSL1 gene, consists of a deletion of 2 nucleotides from position 808 to 809, causing a translational frameshift with a predicted alternate stop codon after 11 amino acids. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, the c.808_809delCT allele has an overall frequency of 0.002% (7/282852) total alleles studied. The highest observed frequency was 0.01% (3/30616) of South Asian alleles. Loss of function alterations in this region of the KANSL1 gene are more common in population databases than expected for likely pathogenic/disease-causing variants (Koolen, 2015). Based on the available evidence, this alteration is classified as pathogenic.

KANSL1-related disorder

Pathogenic:1

Apr 25, 2023

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The KANSL1 c.808_809delCT variant is predicted to result in a frameshift and premature protein termination (p.Leu270Valfs*11). This variant was reported in multiple individuals with Koolen-de Vries syndrome or a neurodevelopmental phenotype. In many cases, the variant arose de novo (Nair et al. 2018. PubMed ID: 30293248; Table S1 - Gabriel et al. 2021. PubMed ID: 34958143; Tolusso et al. 2021. PubMed ID: 33442022; Table S2 - Turner et al. 2019. PubMed ID: 31785789). This variant is reported in 0.0098% of alleles in individuals of South Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-44248700-CAG-C). Frameshift variants in KANSL1 are expected to be pathogenic. This variant is interpreted as pathogenic.

not provided

Pathogenic:1

Apr 01, 2019

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not specified

Uncertain:1

May 04, 2022

Mendelics

Significance:Uncertain significance

Review Status:flagged submission

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

2.0

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over