rs797045307

Positions:

• chr7-97864267-TC-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001673.5(ASNS):​c.478del​(p.Glu160LysfsTer8) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000151 in 1,460,516 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: not found (cov: 33)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: ASNS NM_001673.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 7.11

Genes affected

ASNS (HGNC:753): (asparagine synthetase (glutamine-hydrolyzing)) The protein encoded by this gene is involved in the synthesis of asparagine. This gene complements a mutation in the temperature-sensitive hamster mutant ts11, which blocks progression through the G1 phase of the cell cycle at nonpermissive temperature. Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, May 2010]

CZ1P-ASNS (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-97864267-TC-T is Pathogenic according to our data. Variant chr7-97864267-TC-T is described in ClinVar as [Pathogenic]. Clinvar id is 210339.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ASNS	NM_001673.5	c.478del	p.Glu160LysfsTer8	frameshift_variant	4/13	ENST00000394308.8
CZ1P-ASNS	NR_147989.1	n.2107del		non_coding_transcript_exon_variant	10/19

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ASNS	ENST00000394308.8	c.478del	p.Glu160LysfsTer8	frameshift_variant	4/13	1	NM_001673.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000151 AC: 22 AN: 1460516 Hom.: 0 Cov.: 31 AF XY: 0.0000179 AC XY: 13 AN XY: 726530

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: 0.0000198

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital microcephaly - severe encephalopathy - progressive cerebral atrophy syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 23, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Mar 25, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 13, 2023	Variant summary: ASNS c.478delG (p.Glu160LysfsX8) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 250206 control chromosomes. c.478delG has been reported in the literature in at least one individual affected with Asparagine Synthetase Deficiency. These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	Dec 13, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 05, 2023	This sequence change creates a premature translational stop signal (p.Glu160Lysfs*8) in the ASNS gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ASNS are known to be pathogenic (PMID: 27422383, 30057589). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ASNS-related conditions. ClinVar contains an entry for this variant (Variation ID: 210339). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 27, 2018	The c.478delG variant in the ASNS gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. The c.478delG variant causes a frameshift starting with codon Glutamic Acid 160, changes this amino acid to a Lysine residue, and creates a premature Stop codon at position 8 of the new reading frame, denoted p.Glu160LysfsX8. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.478delG variant is not observed in large population cohorts (Lek et al., 2016). We interpret c.478delG as a pathogenic variant. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs797045307; hg19: chr7-97493579;