17-46171102-G-A
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_015443.4(KANSL1):c.1042C>T(p.Arg348*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000205 in 1,461,852 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_015443.4 stop_gained
Scores
Clinical Significance
Conservation
Publications
- Koolen-de Vries syndromeInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), ClinGen
- Koolen-de Vries syndrome due to a point mutationInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 18 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| KANSL1 | NM_015443.4 | c.1042C>T | p.Arg348* | stop_gained | Exon 2 of 15 | ENST00000432791.7 | NP_056258.1 |
Ensembl
Frequencies
GnomAD3 genomes Cov.: 35
GnomAD4 exome AF: 0.00000205 AC: 3AN: 1461852Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2AN XY: 727236 show subpopulations ⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
Age Distribution
GnomAD4 genome Cov.: 35
ClinVar
Submissions by phenotype
Koolen-de Vries syndrome Pathogenic:4
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This variant is interpreted as a Pathogenic for Koolen-De Vries syndrome, autosomal dominant. The following ACMG Tag(s) were applied: PM2: Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium. PM6: Assumed de novo, but without confirmation of paternity and maternity. PVS1: Predicted nullvariant in a gene where LOF is a known mechanism of disease. -
A known stop-gain variant, c.1042C>T in exon 2 of KANSL1 was observed in heterozygous state in the Proband (Zhang et al., 2024; Zollino et al., 2015). Sanger validation and segregation analysis showed that the variant was present in heterozygous state in the proband and absent in the proband's parents. The variant is present in three individuals in heterozygous state and absent in homozygous state in gnomAD (v4.1.0). The variant is not present in homozygous and/or heterozygous state in our in-house database of 3464 exomes. This variant is likely to result in a premature truncation of the transcript that can either lead to nonsense-mediated mRNA decay or the formation of a truncated protein product. -
[ACMG/AMP: PVS1, PS2, PM2, PP5] This alteration is a null variant in a gene where LOF is a known mechanism of disease [PVS1], is de novo in origin as it was not detected in the submitted parental specimens (identity confirmed) [PS2], is absent from or rarely observed in large-scale population databases [PM2], was reported as a pathogenic/likely pathogenic alteration by a reputable source (ClinVar or other correspondence from a clinical testing laboratory) [PP5]. -
Inborn genetic diseases Pathogenic:1
The c.1042C>T (p.R348*) alteration, located in exon 2 (coding exon 1) of the KANSL1 gene, consists of a C to T substitution at nucleotide position 1042. This changes the amino acid from an arginine (R) to a stop codon at amino acid position 348. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been detected in multiple individuals with Koolen-de Vries syndrome, including multiple cases of reported de novo occurrence (Zollino, 2015; Miller, 2020; St John, 2022). Based on the available evidence, this alteration is classified as pathogenic. -
not provided Pathogenic:1
Note that inversion polymorphisms exist at 17q21.31 which contain partial duplications of the KANSL1 gene and produce novel KANSL1 transcripts. It is unknown if this variant is present in the primary transcript of the KANSL1 gene or an alternate transcript from the duplicated haplotype. (PMID: 22751096); Not observed at significant frequency in large population cohorts (gnomAD); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 33393407, 26424144, 32371413, 36529818, 22751096) -
Intellectual disability Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at