20-32433739-CTG-C

Position:

• chr20-32433739-CTG-C

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 16P and 1B. PVS1 PP5_Very_Strong BS2_Supporting

The NM_015338.6(ASXL1):​c.1544_1545del​(p.Val515GlyfsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000496 in 1,613,832 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: ASXL1 NM_015338.6 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.71

Genes affected

ASXL1 (HGNC:18318): (ASXL transcriptional regulator 1) This gene is similar to the Drosophila additional sex combs gene, which encodes a chromatin-binding protein required for normal determination of segment identity in the developing embryo. The protein is a member of the Polycomb group of proteins, which are necessary for the maintenance of stable repression of homeotic and other loci. The protein is thought to disrupt chromatin in localized areas, enhancing transcription of certain genes while repressing the transcription of other genes. The protein encoded by this gene functions as a ligand-dependent co-activator for retinoic acid receptor in cooperation with nuclear receptor coactivator 1. Mutations in this gene are associated with myelodysplastic syndromes and chronic myelomonocytic leukemia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Pathogenic. Variant got 15 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 20-32433739-CTG-C is Pathogenic according to our data. Variant chr20-32433739-CTG-C is described in ClinVar as [Pathogenic]. Clinvar id is 280245.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr20-32433739-CTG-C is described in Lovd as [Pathogenic].
• BS2: High AC in GnomAdExome4 at 7 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ASXL1	NM_015338.6	c.1544_1545del	p.Val515GlyfsTer13	frameshift_variant	12/13	ENST00000375687.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ASXL1	ENST00000375687.10	c.1544_1545del	p.Val515GlyfsTer13	frameshift_variant	12/13	5	NM_015338.6	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152230 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461602 Hom.: 0 AF XY: 0.00000963 AC XY: 7 AN XY: 727068

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152230 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74370

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 19, 2016

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 27, 2018

The c.1544_1545delTG variant in the ASXL1 gene has been reported previously in the de novo state in an individual with epilepsy (Helbig et al., 2016). The c.1544_1545delTG variant causes a frameshift starting with codon Valine 515, changes this amino acid to a Glycine residue, and creates a premature Stop codon at position 13 of the new reading frame, denoted p.Val515GlyfsX13. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.1544_1545delTG variant is not observed in large population cohorts (Lek et al., 2016). We interpret c.1544_1545delTG as a pathogenic variant. -

Bohring-Opitz syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

3billion

May 22, 2022

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic without evidence for the classification (ClinVar ID: VCV000280245). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Computational scores

Source: dbNSFP v4.3

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: rs777537805; hg19: chr20-31021542;